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Context and aims. DNA metabarcoding strategy was used to sequence the 16S rRNA region of ruminal fluid samples from Nellore cattle fed with concentrate-rich diets in response to modulatory effect of buffering additives calcarea seaweed (Lithothamnium calcareum) and sodium bicarbonate. Methods. Besides characterising the richness and diversity indices of rumen bacterial community, the impact of potentially acidogenic diets on rumen pH, blood parameters, and short-chain fatty acid profile (SCFA) was investigated for which four male Nellore cattle were used, distributed in a 4 × 4 Latin square (treatments × periods). Treatments comprised the same highly concentrated basal diet, and were as follows: T1, without additive (CON); T2, inclusion of 90 g of sodium bicarbonate (BIC); T3, inclusion of 90 g of L. calcareum (L90); and T4, inclusion of 45 g of L. calcareum (L45). Data were analysed in R, in which diversity and abundance at gender level were analysed using Friedman's test, withmeans being adjusted by False Discovery Rate (FDR) correction. The analyses of pH, biochemical parameters and SCFA were analysed using Scott-Knott test and means were evaluated with a significance level of 10% (P < 0.10). Key results. We identified 1474 operational taxonomic units (OTUs) belonging to 52 genera and 16 phyla of bacteria domain. The results showed that bacterial microbiota were dominated by Firmicutes (44.12%), Bacteroidetes (28.29%), and Proteobacteria (5.88%). Animals fed with L90 demonstrated greater abundance and ruminal diversity for the Prevotella genus (P < 0.07% and P < 0.09% respectively), whereas cattle supplemented with L45 demonstrated greater diversity of the Fibrobacter genus (P < 0.05). There were differences in molar proportion for acetic (P < 0.07%) and valeric (P < 0.03%) acids in the period before feeding. Higher blood lactate concentrations were observed in animals supplemented with L45 (P < 0.06%), while animals that received treatments L90 and BIC presented lower levels of blood lactate. This metabolite was lower in animals fed with 90 g of sodiumbicarbonate and L. calcareum daily. These treatments also reduced the concentration of acetic acid and increased that of valeric acid, and improved ruminal diversity. Conclusions and implications. Our results supported this choice to improve ruminal function, with a great prospective of better weight-gain performance in Nellore cattle. [ABSTRACT FROM AUTHOR]

Context. The New Zealand Thoroughbred breeding industry is heavily focused on producing horses for the export market and there has been a reduction in the number of horses racing in the past 20 years. The impact of these production constraints, and changes in production focus, have not been described at a national herd level. Aim. To describe the breeding management, reproductive performance, and careers of the New Zealand Thoroughbred broodmare herd during the 2005/06-2015/16 breeding seasons. Methods. The demographics, population structure, reproductive efficiency, breedingmanagement and career descriptors of Thoroughbred mares were examined using descriptive analysis. Gestation length was modelled using a linear mixed effects model. The impact of different variables on breeding career were quantified by calculating odds ratio. Results. There was a consistent reduction in the size of the national broodmare herd over the 10 years investigated. Half of the mares not retained for breeding were mares that were breed to low-cost stallions. Despite a short (~100 days) commercial breeding season few (20%) mares were mated early in the season (September), with most mating (70%) occurring between October and November. The 27 days mean foaling to conception interval (FCI) suggests that FCI was artificially shortened and most pregnancy was achieved within first oestrus cycle post-partum. Mare career length and lifetime productivity was positively associated with the stud fee of the first stallion that the mare was mated to and number of foals registered for racing. Conclusion. Mare replacement and loss within the national herd was disproportionately associated with mares that were producing foals for a contracting domestic racing market. There was a constricted breeding season with most mares being mated within the first oestrous cycle post-partum. Mare retention and breeding success were positively associated with the service fee of the sire and progeny that had raced, reflecting the commercial pressure of the industry on mare management. Implication. The changes in the broodmare herd and management reflects the increasing proportion of the industry focusing on breeding foals that will appeal to the export market. The economic drivers for early born foals provide management challenges as these are not aligned with the optimal reproductive season of the horse. [ABSTRACT FROM AUTHOR]

With the increase in worldwide demand for seafood, the current plateau in production from wild-harvest fisheries has resulted in the rapid growth of the aquaculture sector. Aquaculture relies on quality ingredients such as fishmeal, but cost concerns have led to the investigation of a variety of alternate plant and animal by-products and microbial sources as aquafeed ingredients. Evaluation of alternative aquafeed has traditionally focused on their effects on the growth and immune status of the fish and not always on market-driven assessments of the final edible product. One of the commonly researched groups of alternative ingredients is seafood waste, which, after transformation, has potentially beneficial nutritional characteristics. Transformation, which includes rendering, enzyme hydrolysis and use as a feed source for insects and microbial species, is intended to provide stability and enhance the logistical feasibility of the waste as an aquafeed ingredient. This review discusses transformed fish waste in aquafeeds and describes some of the market and end-user implications (composition, edible safety and quality, sustainability metrics and consumer perceptions) of this approach. With the rapid growth of aquaculture, there has been extensive research on a range of alternate ingredients for aquafeed. Such investigations have usually focused on growth of the target species. A possible gap is the assessment of the aligned edible product for a range of market-driven parameters such as nutritional composition, quality, consumer perceptions and sustainability metrics. This review focuses on alternate aquafeed ingredients transformed from seafood waste and investigates analyses aligned with information pertinent to markets or end-use. [ABSTRACT FROM AUTHOR]

This review provides an outline of some of the challenges facing nutritionists in the Australian aquaculture industry. It commences with a brief description of how aquaculture nutrition differs from that for terrestrial livestock – the challenges of providing nutrition in aqueous environments, the diversity of species and the high trophic level of most. Specific challenges of aquaculture nutrition are then discussed in further detail, including the difficulty of measuring feed intake and digestibility, the limited ability to use carbohydrates for carnivores, and the specific requirements of species for lipids, including cholesterol, phospholipids, long-chain polyunsaturated fatty acids and carotenoids. The review then examines how environmental, social and governance concerns are leading to new trends in nutrition for the Australian industry. This includes topics such as the replacement of wild-caught fish meal and fish oil, in terms of both sources of omega-3 lipids and protein. For the former, possible solutions include greater use of seafood trimming, algal oil, and GMO-derived products. For the latter, solutions can include use of livestock render, plant protein meals, fermented products, and insects. Nutrient discharge is also a concern for the industry and nutritionist can assist by improving digestibility and nutrient retention from feeds. Finally, the carbon footprint of aquaculture is leading to new directions for industry and, in turn, for the field of aquaculture nutrition. Aquaculture feed formulations are being re-imagined. Not only do formulations have to meet the rigid nutrient requirements of the high trophic species cultured, but they will also have to adhere to increasing expectations of sustainable farming, animal health and welfare, and seafood quality. Environmental, social and governance concerns are steering the aquaculture industry in new directions and influencing nutrition research. This review provides an outline of some of the challenges facing nutritionists, which are leading to new trends for feeding Australian aquaculture. [ABSTRACT FROM AUTHOR]

Nutritional management in rangeland beef cattle systems prioritises optimal body condition scores at calving for improved fertility and reproductive success. However, this focus often overlooks short-term dietary deficiencies before calving, which can lead to adverse outcomes for neonatal calves. This review explores the effects of beef cow malnutrition during the periparturient period on colostrum production, lactation onset, and passive immunity transfer to calves. Additionally, it discusses the long-term impact of such malnutrition on the offspring. By understanding how nutritional interventions affect the transition from gestation to lactation, it becomes possible to enhance calf health and survival in arid tropical environments. Commonly occurring short-term dietary restrictions, particularly protein deficiencies, can disrupt the hormonal equilibrium, resulting in reduced colostrum volume and quality, hindering calf growth and increasing mortality risks. Furthermore, dietary restrictions during this period affect critical physiological processes such as mammary gland blood flow and fetal small-intestine development. The review explores how these constraints influence colostrum production and immunoglobulin absorption by neonatal calves. Additionally, it highlights the significance of addressing other common nutrient deficiencies such as phosphorus and water and investigates the potential benefits of supplementing microbial products to enhance rumen function and protect cows from inflammation. Ultimately, addressing malnutrition during pregnancy is essential to prevent negative impacts on offspring performance, including alterations in carcass composition and muscle marbling. Consequently, cattle producers who aim for superior muscle marbling in the carcass by using costly genetics should give priority to enhancing nutritional programs for late-pregnant cows. In conclusion, a comprehensive understanding of the effects of malnutrition during the periparturient period on colostrum production, passive immunity transfer, and overall calf health is crucial for developing effective nutritional interventions that improve colostrum production, passive immunity transfer, and overall calf health in rangeland beef cattle systems. Ensuring proper nutrition during the peripartum period is crucial for healthy calf growth and survival. According to this review article, short-term dietary protein restrictions can disrupt hormonal balance, reduce colostrum quality and volume, and increase the risk of calf mortality, regardless of the cow's body condition score. The review highlights the need for cattle producers to develop improved nutritional programs for late-pregnant cows, particularly those focused on high muscle marbling in the carcass. [ABSTRACT FROM AUTHOR]

Precision nutrition regimes currently rely on the assumption that broilers will grow in a steady and predictable way on a daily basis, with the continuous deposition of nutrients into muscle or, in the case of laying hens, into an egg. However, it has been observed that this is not the case for egg production, with Ca requirements being aligned with eggshell formation. Recent research has suggested that muscle is also deposited at differing rates over a 24-h cycle. The circadian rhythm synchronises various biological processes to oscillate within a 24-h cycle. Thus, the cyclic nature of body systems should be explored, to determine whether consideration of the circadian rhythm is required for precision nutrition programs, achieving peak efficiency of performance and accurate nutrient requirement recommendations. Recent advances in nutrition have demonstrated the powerful effect of the circadian rhythm on human health and animal growth and production. Therefore, this review discusses recent circadian-rhythm research with relevance to poultry. Specific focus is given to the interaction of the circadian rhythm with diet and dietary nutrients, for the precision nutrition of poultry and optimising production. Poultry are fed with the assumption that muscle growth and egg formation require the same steady flow of nutrients throughout the day. However, in the case of egg production we know this is not the case, and recent evidence suggests that muscle deposition may also follow cyclic patterns. Therefore, this review discusses recent research on the circadian rhythm, which synchronises various biological processes within a 24 h cycle, and its relevance to poultry production. [ABSTRACT FROM AUTHOR]

Prebiotics are non-digestible carbohydrates that selectively stimulate the growth of beneficial bacteria. Prebiotic supplementation into poultry diets results in a decreased rate of pathogenic bacteria colonisation in the gastrointestinal tract. It also enhances production of volatile fatty acids and lactic acid, which provide the bird with energy. This results in improved host gastrointestinal health and productive performance. Oligosaccharides are the most notable prebiotics in poultry nutrition. Examples of prebiotic oligosaccharides include xylo-oligosaccharides, fructo-oligosaccharides, and galacto-oligosaccharides. Oligosaccharides are derived from hydrolysis of non-starch polysaccharides (NSP). They are manufactured from plant sources, synthesised by physiochemical methods or enzymatic processes. The effects of oligosaccharides occur primarily in the caeca; oligosaccharides bypass the small intestine and reach the caeca, where they are readily fermented by beneficial bacteria, such as those in family Lactobacillaceae and Bifidobacteriaceae. Caeca function is generally poorly understood, despite extensive reviews and studies in this field. A deeper understanding of the factors that influence ability of the caeca to effectively utilise oligosaccharides is warranted. This would allow new prebiotic products and NSP- degrading enzymes to be developed, targeted to specific diets and scenarios. This is required, given the lack of consistency observed in the outputs derived from different studies assessing oligosaccharide efficacy in poultry diets. A key hinderance to progression in this field is that authors rarely analyse the oligosaccharide content and composition in the test diets and products, or in the bird's gastrointestinal tract. This review examines the mechanisms behind how oligosaccharides induce prebiotic effects in poultry, by identifying the role of the caeca in NSP digestion and identifying the impact of oligosaccharides on caeca microbiota and short-chain fatty acid composition. Supplementing prebiotics, specifically short-chain sugars called oligosaccharides, into poultry diets has been shown to improve bird gastrointestinal health and productivity. However, bird responses to these oligosaccharides are inconsistent among research studies, suggesting that it may not always be economically beneficial to supplement them into poultry diets. This review examines the mechanisms behind how oligosaccharides induce prebiotic effects in poultry, to better understand how to the achieve the greatest benefits from using them, aiding development of new prebiotic products. [ABSTRACT FROM AUTHOR]

Context: Deer antler base is a part of deer antler and a traditional Chinese medicine, which is effective in treating mammary gland hyperplasia and other diseases. However, deer antler base is very hard and not easy to crush, resulting in its under-utilisation and a waste of resources. At present, the potential mechanism of deer antler base in the treatment of diseases is still unclear. Aim: To encourage its utilisation and research, it is crucial to comprehend its composition and identify the key effective components. Methods: To explore the differences in metabolites between antler bases of different deer species, red and sika deer antler bases were used as samples, and metabolites from both deer antler base samples were screened and identified by Ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Key results: In all, 151 metabolites were identified in both red deer and sika deer antler bases. Metabolite types did not differ between the antler bases of red and sika deer, while there was some difference in metabolite abundance. After principal-component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA); a total of 43 metabolites with significant differences were identified. KEGG annotation showed that pathways with the most metabolites enrichment were mainly related to lipid and amino acid metabolism. The pathways significantly annotated with differential metabolites were mainly related to amino acid metabolism. Conclusions: On the basis of untargeted metabolomics analysis, this study systematically showed the differences in metabolites composition and abundance in antler bases between two deer species from a metabolomics perspective. The composition and abundance of metabolites in red deer antler base were similar to those in sika deer antler base, but the endogenous metabolites in different deer antler bases had some differences. Implications: The present study found that there was no significant difference in endogenous metabolites in antler bases between red deer and sika deer, which indicates that deer antler bases of different deer species may have similar medicinal value. It will provide some theoretical basis for research, development, and utilisation of antler bases. Deer antler base is a kind of traditional Chinese medicine, but the medicinal value of different deer antler bases has not been systematically evaluated. The present study used UHPLC–MS/MS and found that the composition of metabolites in antler bases of red and sika deer is similar, but there are differences in abundance. Investigating the differences in endogenous metabolites of different deer antler bases and the efficacy components of antler base is important for the utilisation of this traditional Chinese medicine. [ABSTRACT FROM AUTHOR]

Context: In sows, the development of insulin resistance (IR) during late gestation and lactation favours a productive gap associated with low feed intake during lactation, which is reflected in the herd profitability. Therefore, the development of rapid-use tests to diagnose IR on farms will be very useful. Aims: We aimed to validate the triglyceride and glucose (T-G) index as a rapid diagnostic test to diagnose IR in sows during late gestation and lactation. Methods: The homeostatic model to evaluate IR (HOMA-IR) was used as a reference. Sixty sows (farrowing 1–5) were selected for blood sampling during late gestation and lactation. In the total number of samples collected (n = 480), the glucose, insulin, and triglyceride concentrations were determined to estimate the HOMA-IR and T-G index. Receiver operating characteristic curves were used to determine cut-off values for diagnosing IR using the T-G index. Key results: The highest (P < 0.05) values of HOMA-IR and T-G index were found between Day 110 of gestation and Day 3 of lactation, regardless of the farrowing number evaluated. The area under the curve for the T-G index was 0.83 (95% CI 0.78–0.88). The best overall cut-off point for diagnosing IR by using the T-G index was 4.24 (86% sensitivity and 77% specificity). The association between the T-G index and HOMA-IR was 0.68 (P < 0.0001), regardless of the farrowing number and productive stage (late gestation, early lactation, and late lactation). According to the farrowing number and productive stage, the best cut-off points were 4.21 (sensitivity 86% and specificity 73%), 4.20 (sensitivity 83% and specificity 73%), and 4.20 (sensitivity 88% and specificity 92%) for sow's first and fourth farrowing, and late gestation respectively. Conclusions: The T-G index is a reliable field test for IR diagnosis in sows during late gestation and lactation. Implications: The T-G index test evaluated for the diagnosis of IR in sows is an approach that could be significantly exploited at the farm level. This test could become a support tool to maximise the productivity of the sow, since the development of IR could be modulated through zootechnical practices. The low feed intake of the lactating sow associated with insulin resistance (IR) is a key factor to manipulate due to its effects on the productivity and profitability of the herd. By implementing tools at the farm level that help diagnose IR in the sow in the most important periods (late gestation and lactation), nutritional and management strategies could be generated that can reduce the effects of IR and thus maximise sow productivity and profitability. [ABSTRACT FROM AUTHOR]

Context: Pinus densiflora bark extract (PBE) has attracted more attention in the livestock industry due to its antioxidant activity, antibacterial activity and beneficial nutrient utilisation. Aims: This study aimed to determine the effect of dietary PBE concentration on growth performance, antioxidant activity, nutrient digestibility and intestinal health in broilers. Methods: In total, 180 1-day-old Arbour Acres male broilers were randomly divided into four treatment groups (0, 100, 200, 300 mg/kg PBE respectively), with five replicates per group and nine broilers per replicate, and the treatments were applied for 42 days. Results: Dietary PBE supplementation improved significantly antioxidative status and gene expression of antioxidant enzymes such as SOD1, GPx1 and CAT in broilers. Moreover, PBE supplementation increased the intestinal absorption and mRNA expression level of the tight junction proteins. In addition, the diet supplemented with PBE significantly increased the villus height (P < 0.01) and the villus:crypt ratio (C:V) (P < 0.05) in jejunum. Although supplementation of 300 mg/kg PBE significantly decreased nutrient digestibility and activities of lipase and amylase (P < 0.05), supplementation of 200 mg/kg PBE had no negative impact on digestibility. Conclusion: This study showed that supplementation of 200 mg/kg PBE improves the antioxidant status and the intestinal health without adverse impact in broilers. Implications: This study has provided scientific insight and rationale to protect broilers from oxidative stress and intestinal disease. Pinus densiflora bark extracts (PBE) have attracted more attention in the livestock industry due to not only their beneficial physiological functions but also their abundance in source and quantity. This study indicated that PBE supplementation had beneficial effects on antioxidant activity and intestinal barrier function, and 200 mg/kg of PBE had no undesirable effect on the nutrient digestibility. This study has provided scientific insight and rationale to protect broilers from oxidative stress and intestinal disease. [ABSTRACT FROM AUTHOR]

Context: Native chicken farming has potential for development in several areas in Indonesia, because it is a very familiar practice and has specific community value. Both men and women have a role in raising native chickens. Aims: To construct a profile of the poultry system and determine the potential socio-economic impacts for meeting community needs as a basis for the development of future native chicken enterprises. Methods: The study was conducted in five areas in South Sulawesi, Indonesia, including Barru, Enrekang, Jeneponto, Maros, and Soppeng regencies. Interviews included 385 respondents (55.06% men and 44.94% women), most of whom were in the productive-age category (defined as 31–62 years of age) and were elementary school graduates. The number of family members was low, as was the number of chickens owned, being up to 25 chickens raised per year. Key results: Native chicken farming was determined to have a moderate socio-economic impact on communities, as the number of chickens owned was relatively low. Native chickens are used for consumption, income generation and savings, and as complements in religious and traditional ceremonies. The potential target markets for native chickens are diverse, including individual end consumers, restaurants, local markets, and inter-regional markets. The amount of income from selling chickens varies depending on the quantity sold and the price. The price of chicken will rise under certain conditions, such as during religious and traditional events. Technical production constraints to market development include inadequate housing, lack of sanitation, non-optimal disease management, and low use of vaccinations. The primary market constraint is that the rearing locations can be far from the city centre, and the number of chickens that can be produced for sale is low. Conclusions: Poultry management dynamics, such as feeding, housing, and sanitation, must be considered to expand native chicken production. It is essential to identify solutions for selling native chickens to significantly increase household income. Native chickens have a socio-economic impact, raising the family income, as complements in religious and traditional ceremonies, and affecting the social status of breeders. Implications: Information regarding the potential and prospects of native chicken farming from a socio-economic perspective can encourage communities to maintain and develop livestock enterprises to support the provision of animal protein for consumption and traditional uses, and to increase household incomes. The present study provides important information about the potential and prospects of native chicken farming. The social impact of native chicken farming includes increasing the social status and using chickens as complements in religious activities. The economic impact includes being a source of family income because the price is more expensive than for broiler chickens, and there is special demand for native chicken. Therefore, the native chicken farming business needs to be developed and its economy of scale improved. [ABSTRACT FROM AUTHOR]

Context: The minimum requirements of physically effective neutral detergent fibre of forage (peNDF-F) in finishing diets for feedlot lambs has not been consolidated. Aims: The present study evaluated the effect of increasing levels of peNDF-F on growth performance, blood metabolites, carcass characteristics, and ingestive behaviour of feedlot lambs fed a whole corn grain-based diet. Methods: Forty-five Dorper × Santa Inês rams, with an initial bodyweight (BW) of 22.6 ± 5.3 kg (mean ± s.d.) and 88 ± 10 days old (mean ± s.d.), were used. The experimental design was a randomised complete block (five treatments and nine blocks), defined by the initial BW and age at the beginning of the experiment. The experimental diets were formulated to be isonitrogenous and isoenergetic. The experimental diets were as follows: ground corn-based diet with 72 g/kg of peNDF-F from coastcross (Cynodon sp.) hay (CONT, positive control); whole corn grain-based diet without coastcross (Cynodon sp.) hay (0peNDF-F); whole corn grain-based diet with 36 g/kg of peNDF-F from coastcross (Cynodon sp.) hay (36peNDF-F); whole corn grain-based diet with 72 g/kg of peNDF-F from coastcross (Cynodon sp.) hay (72peNDF-F); whole corn grain-based diet with 108 g/kg of peNDF-F from coastcross (Cynodon sp.) hay (108peNDF-F) (DM basis). Key results: The increasing concentrations of peNDF-F in whole corn-based diets reduced the dry-matter intake (P < 0.0001), average daily gain, feed efficiency, final BW, carcass characteristics (P < 0.05), AST (P = 0.01), and glucose concentration (P ≤ 0.03). Additionally, the increasing concentrations of peNDF-F decreased the area (P ≤ 0.02) and the length of ruminal papillae (P = 0.008). The rumination and chewing times (min/day) showed a quadratic response; a longer rumination time (P = 0.001) was observed with 72peNDF-F and the longer chewing time (P = 0.006) with 108peNDF-F. Conclusions: Whole corn grain-based diets can be used without the addition of peNDF-F for lambs. Implications: Thus, utilisation of whole corn grain diet can be a strategy to successfully feed and fatten lambs to slaughter. This study aimed to evaluate the effects of increasing concentrations of peNDF-F on growth performance, and carcass characteristics of feedlot lambs fed a whole corn grain-based diet. The results showed that increasing concentrations of peNDF-F reduced DMI, ADG, FE, carcass characteristics, and the area and length of ruminal papillae. However, whole corn grain-based diets can be used without the addition of peNDF-F in lambs, which can be a successful strategy for feeding and fattening lambs for slaughter. [ABSTRACT FROM AUTHOR]

Context: The Patagonian huemul, an endangered Odocoilinedeer, has an estimated 350–500 individuals remaining in Argentina. Today's population size, representing a numerical reduction of >99% of original estimates, is fragmented into small groups along ~2000 km of Andean mountains. The species' numbers were heavily reduced by past overexploitation and they disappeared in areas of high anthropogenic activity, predominantly the fertile valley bottoms. Aims: This research delineates the current potential distribution of Patagonian huemul by using climatic indicators, topographic and vegetational proxies, and anthropogenic pressure, to determine the relevance of the climatic envelope on current distribution. Methods: Occurrence records (latitude and longitude) were compiled (n = 159) by consulting the literature. Twenty environmental variables were used (WorldClim database) and two other representative environmental variables (normalised difference vegetation index (NDVI) and enhanced vegetation index (EVI)) were added to test their predictive power. We added the human footprint index (HFP) as a variable to control for model bias. Using the maximum entropy algorithm (MaxEnt), we modelled the species' potential distribution. We designated the historical distribution as area M. Additionally, we calculated three areas of distribution: current, historical and potential. Finally, we calculated distributional retraction of the species and area lost per year. Key results: The model showed good predictive power (AUCTest = 0.764 ± 0.091). However, low values were obtained for AUCtrain and AUCprom for the different predictor scenarios. Although the model shows the interaction among several climatic, environmental, and topographic variables, the human footprint index (39.9%) was the variable that most influenced the current potential distribution of this species. Conclusion: Our model shows that most of Patagonia's surface is climatically suitable for huemul. This suggests that the causes of distributional retraction are not related to limitations imposed by the climate envelope, but rather concur with recent research showing impact owing to the species' behavioural response to anthropogenic activity. Implications: Current populations are small, fragmented, and confined to poor-quality sites. Although the species is currently found mainly within protected areas, management actions must be initiated that promote innovative strategies in unprotected areas, as well as high-value habitats, particularly as protected areas contain limited fertile lower-valley habitats. Different anthropogenic factors heavily reduced the number of the huemul, an endangered Patagonian deer. Our aim was deliminated potencial distribution of huemul by using climatic indicators, topographic, vegetational, and anthropogenic. Our model shows that most of argentine Patagonia is climatically suitable for huemul, suggesting that the causes of the distributional retraction are linked to factors derived from the combination of characteristics of the species' biology and the increased anthropic. Therefore, it is necessary to conduct management and protection actions for species. [ABSTRACT FROM AUTHOR]

Context: Conversion of native vegetation to cropland is one of the most widespread anthropogenic landscape alterations, particularly in the Great Plains region of the United States. Mule deer occur throughout the Great Plains; however, it is the south-eastern edge of their geographical distribution, and few populations coincide with dense cropland. The rapidly depleting Ogallala Aquifer supplies irrigation to row-crops throughout the region, which will likely shift towards dryland agricultural practices in the near future. Aims: We sought to understand how cropland use influences morphology, body condition indices, reproductive output, and survival of free-ranging mule deer. Methods: We accumulated a multi-year, longitudinal dataset of movement and morphology for 146 mule deer in the Texas Panhandle. We linked seasonal cropland use with observed morphology, body condition metrics, and reproductive output via linear mixed-effect modelling and assessed the influence of cropland on annual survival by using Cox proportional hazard models. Key results: Mule deer that did not use cropland at any time during the year exhibited morphological and nutritional indices similar to those that did; except body-fat percentage being greater for mature (≥4-year-old) males that used cropland. Further, cropland use did not predict survival probability. Analyses of cropland use during seasons defined by life-stage showed context-dependent nutritional benefits. Use of cropland during winter following reproduction demonstrated an increase in young (≤3-year-old) male antler size and body mass and summer crop use increased body condition for all males. Female mule deer that utilised cropland before pregnancy had increased probability of successful reproduction, demonstrating a potential capital investment strategy in reproduction. Conclusions: Cropland does not limit morphology or survival of mule deer; however, additive use of row-crops can provide a nutritional buffer and enhanced reproductive output for individuals that choose to utilise it. Implications: Our study demonstrates important population-level interactions with the environment for a species near the extent of their geographical distribution. Conversion of row-crop farming from aquifer depletion or climate shifts may not diminish mule deer populations, but these changes may alter specific habitat-nutritional health relationships that can influence population performance and future conservation efforts. The rapidly depleting Ogallala Aquifer supplies irrigation to row-crops throughout the United States Great Plains, which will likely shift towards dryland agricultural practices in the next 20 years. These areas are the fringe of the mule deer distribution and cropland serves as a nutritional buffer against naturally occurring periods of nutrient limitation. Row-crop farming conversion from aquifer depletion may not diminish mule deer populations, but these changes may alter specific habitat–nutritional relationships that influence population performance and conservation efforts. [ABSTRACT FROM AUTHOR]

Climate change is one of the most important threats to biodiversity both for the relevance of the impacts and the speed of the process. Deer are widely affected by climate change even if the outcomes of the interaction with a given species are equivocal. Cold-adapted species are in general more susceptible to climate-change impacts, but even eurythermic species such as roe deer can be affected in their population dynamics. Both indirect effects, such as the mismatch between vegetation flushing and birth date, or the reduction of food accessibility, and direct ones, such as the impact of temperature causing heat stress, on activity rhythms, habitat selection and ultimately food intake, can have important consequences. In deer species, the ability to cope with these changes is dependent on the timing of resource acquisition, being different in capital and income breeder, but also on the breeding biology with special reference to the ability to shift reproduction in time. A number of consequences are caused by the impact of climate change on populations and individuals; notably, relevant shifts in species distribution have been described in different parts of the world. Moreover, changes in young and adult body size, in juvenile survival, in population dynamics and in the timing of biological cycles, such as rutting time or birth season, have been observed in a number of species. Changes in hunting regulations and management or conservation actions may be necessary to buffer the impacts of climate change, and some species or populations may be threatened with extinction or extirpation if proper measures of conservation are not adopted. Deer are widely affected by climate changes. We conducted a literature review of direct effects, such as the impact of temperature causing heat stress, and indirect impacts, such as the reduction of food accessibility. Changes in body size, juvenile survival, population dynamics and reproductive timing have been observed in different parts of the world. Here we discussed about the ability of deer to cope with these changes by different species. [ABSTRACT FROM AUTHOR]

Context: It is common practice to manage red deer on highly digestible easily harvested forage during winter on New Zealand deer farms, particularly in areas that experience low or no pasture growth during this period. However, not all individuals within these production systems perform equally. Aims: To investigate foraging behaviour of young red deer and liveweight gain of young red deer and wapiti crossbred sire lines when offered two contrasting winter forage diets. Methods: One hundred and sixty-three rising 1-year-old female red deer and red deer wapiti crossbreds representing five red deer and two wapiti sires, were split into two management groups balanced by sire and liveweight and managed on either an easily harvested highly digestible diet (forage kale) or a harder-to-harvest more poorly digestible diet (pasture) for a 6-week period during winter. Foraging behaviour was monitored on 95 red deer yearlings by using GPS collars over a 2-week period. Liveweights were recorded at the start and end of the 6-week period. Key results: Progeny managed on the kale treatment exhibited an extended activity period during the dawn period and a suppressed activity period during the middle of the day. Progeny managed on the pasture treatment exhibited frequent shorter activity periods from dawn to dusk. Time spent foraging and the number of foraging bouts greater than 5 min in duration were different among progeny of different sires. These differences in behaviour did not affect liveweight gain. Liveweight gain over the 6-week trial period was significantly higher for progeny from one wapiti sire than for all red deer sire progeny while being managed on the kale diet (P < 0.001), but there were no differences among progeny on the pasture diet. Conclusion: Foraging behaviour varied considerably between sire lines and appeared to vary between forage type, but there were no correlations between behaviour and liveweight gain in this trial. Implications: Forage type offered to young red deer may alter their foraging behaviour. Offering an easier to harvest high digestible forage diet may increase liveweight gain of progeny that have a higher genetic potential to grow during the winter period. Growth rate of young red deer over their first year of life is a key determinant of deer farm profitability and varies considerably across the industry, within farms and among years. GPS data collected from young deer managed on two contrasting winter feed types demonstrated foraging behaviour variation consistently between sire lines. Foraging behaviour did not explain the variation in productivity that is experienced in the industry in this trial, but indicated that beneficial foraging behaviour traits could be selected for in the future. [ABSTRACT FROM AUTHOR]

Context. Intensive livestock production is challenged by frequent occurrence of contagious livestock diseases. Advanced diagnostic tools, such as quantitative polymerase chain reaction (qPCR), have been found to improve the precision and speed of veterinary diagnostics. Aims. This study develops and applies an analytical quantitative framework to investigate the potential farm economic benefits of introducing an advanced and rapid diagnostic tool that allows veterinarians accurately and fast to detect the load and composition of pathogens in production animals, compared with a scenario where decision-making is based on aggregate prevalence data. Methods. A probabilistic budget simulation model for livestock production was developed, on the basis of farm-accounts data, epidemiological prevalence, mortality and morbidity data from official statistics, veterinary practice and literature findings, as well as experimental data regarding sensitivity and specificity of the specific diagnostic tool. Key results. The framework was used to assessthe expected economic gains of qPCR diagnostics for calf pneumonia and weaner pig diarrhoea. In both cases, positive economic gains were found, namely, 7.8%and 3.1%of gross margin in Danish calf production and weaner production respectively. Conclusions and Implications. Use of rapid advanced diagnostic tools to diagnose calf pneumonia or weaner pig diarrhoea can lead to economic gains for farmers and improve the efficiency in use of resources in livestock production. [ABSTRACT FROM AUTHOR]

Context. Biodegradation of agricultural wastes by enzyme from microorganisms, especially white rot fungi has been promising in degrading structural carbohydrates or structurally modifying proteins and their anti-nutritional properties thereby producing high quality products. Aims. To evaluate the nutrient intake, body weight changes, digestibility and nitrogen utilisation of West African dwarf goats (WADG) fed Pleurotus tuber-regium treated cassava root sievate (PTRCRS) based diets. Methods. The experimental diets were formulated such that PTRCRS was included in the different diets at 0, 20, 40 and 60% inclusion levels. Thirty-two WADG between six and eight months old averaging 5.26 kg in weight were randomly divided into four groups of eight goats each. The groups were randomly assigned to four experimental diets {T1 (0%), T2 (20%), T3 (40%) and T4 (60%)} in a completely randomized design. Each animal received a designated treatment diet in the morning (08:00 h) for 90 days. Feed offered was based on 3.5% body weight per day in addition to 1 kg wilted chopped Panicum maximum which was fed at 16:00 h. Fresh drinkable water was provided ad libitum. Key results. There were significant (P < 0.05) differences for dry matter intake (DMI), DMI as percentage of body weight (% BW), crude protein (CP), organic matter (OM), neutral detergent fibre (NDF) and acid detergent fibre (ADF) intakes. Daily weight gain was significantly (P < 0.05) improved in T3 and T4. Feed conversion ratio decreased (P < 0.05) with increasing levels of PTRCRS. Dry matter, CP, crude fibre, NDF and ADF were better (P < 0.05) digested in T4. Nitrogen intake was higher (P < 0.05) in T4 (19.62 g/day) and lowest in T1 (12.39 g/day). Nitrogen balance, nitrogen retention and nitrogen absorbed were significantly (P < 0.05) higher for T4 goats. Conclusion. Incorporation of PTRCRS in WAD goat diets generally enhanced intakes, body weight gain, nutrient digestibility and nitrogen utilisation. Implications. The treatment of cassava root sievate, which is in abundance and hitherto without any known economic value other than causing environmental nuisance with PTR, could solve the challenges of feed scarcity which has been a major factor in ruminant production. The feeding of WAD goats with PTRCRS generally enhance their performances. [ABSTRACT FROM AUTHOR]

Context. Different methods of weaning have been validated to reduce the stress of calves. A novel approach has been described by ranchers whereby the zebu calves are kept in the same pasture with trainer's cows, however, no scientific evidence is available to date. Aims. This study investigated the effect of different weaning methods on the physiological responses, temperament, and post-weaning performance of calves. Methods. One hundred and eighty three Nellore calves were used, including 93 males (initial bodyweight: 219.8 ± 3.25 kg (avg ± s.e.), initial age: 244 ± 14.3 days (avg ± s.e.) and 90 females (219.7 ± 3.25 kg, 246 ± 14 days (avg ± s.e.)). The calves were randomly assigned to three weaning methods: Abrupt - total separation of dam and calf; Fenceline - physical separation between dam and calf by wired fence; and Leadership - total separation between dam and calf and use of social facilitator cows. Heart rate, respiratory rate and blood samples for cortisol analysis were taken on Days 0, 1, 4, and 7 post-weaning. Temperament was assessed on Days 0, 7, and 82. Performance and body condition score (BCS) was measured at 0, 42, and 82 days post-weaning. Key results. No interaction (P > 0.05) between the weaning methods and sex of the calves was detected. Heart and respiratory rates were not influenced (P > 0.05) by weaning methods on Days 1 and 7 post-weaning. Furthermore, females showed higher heart rate at Day 7 post-weaning (P < 0.05). Weaning methods and sex of calves did not affect the cortisol levels (P > 0.05). Calves on Fenceline and Leadership weaning methods had higher final bodyweight and average daily gain (ADG) from weaning until 82 days post-weaning (P < 0.05) compared to the Abrupt weaning method, which had negative ADG (-26 g/day) on the first 42 days and the lowest bodyweight until 82 days post-weaning (P < 0.05). Conclusions. The presence of social facilitators at weaning, using dams in the Fenceline method or non-related cows in the Leadership method, ensures greater post-weaning performance. The Leadership method can be the most advantageous due to its easy handling. Implications. The weaning strategies contribute to good animal performance and shorten the post-weaning and finishing phases. [ABSTRACT FROM AUTHOR]

Context. Decreasing enteric methane emissions from small ruminants is important because methane is a greenhouse gas and a major contributor to global warming. Aim. The objective of this work was to test the effect of a dietary premix consisting of a blend of essential oils, bioflavonoids and chestnut tannins (EOP, essential oils and polyphenols) on methane emission from dry non-pregnant ewes. Methods. Twenty-four dry Sarda ewes were allocated to two homogenous groups: control and treatment groups. Both were fed with a total mixed ration, and the treatment group was supplemented with 1 g/day.ewe of EOP blend. Each animal followed a 20-day adaptation period before methane emission measurements. Methane emissions were measured using a ventilated hood system equipped with a digital gas analyser. Key results. The addition of a dietary EOP blend to the total mixed ration did not affect feed intake and nutrient digestibility. Ewes that received the EOP blend had a 13% lower methane yield than ewes that received the control diet (22.4 vs 25.5 g of CH4 per kg of dry matter intake; P < 0.05, respectively). The EOP blend had no impact on daily methane emission when calculated as g CH4/ewe or g CH4/kg bodyweight. Conclusions. The EOP blend at a daily dose of 1 g/day.ewe decreased methane yield under the experimental conditions described in this work. Implications. Feeding an EOP dietary blend to ewes can decrease methane emission. These results were obtained in vivo with typical farm conditions, suggesting that a similar response may occur in field conditions. [ABSTRACT FROM AUTHOR]

Context. Providing feed is the largest cost in beef production. Genetic variation exists in feed efficiency traits in young cattle but the genetic associations with feed efficiency traits in cows are poorly understood, but if strong and favourable, they might be used to improve feed efficiency of cows. Aim. To examine the phenotypic and genetic relationships among feed intake, feed efficiency, body composition and cow milk yield measured in young cattle and in cows. Methods. Data on 1783 young Angus, Hereford, Polled Hereford and Shorthorn bulls and heifers, and for 751 of the females as cows, were used to calculate the phenotypic and genetic relationships among feed efficiency traits, body composition and cow milk yield measured postweaning and in mature cows. The young cattle were tested for feed intake and feed efficiency at approximately 9 months of age and the females, after two calvings, were tested again as non-pregnant, non-lactating cows at approximately 4 years of age. Key results. At the postweaning test, the heritability estimates for feed intake, average daily gain, test weight, residual feed intake (RFI), feed conversion ratio, rump fat depth and eye-muscle area were 0.47, 0.32, 0.46, 0.42, 0.28, 0.47 and 0.20 respectively. Corresponding heritability estimates in the cow test were 0.27, 0.35, 0.74, 0.22, 0.30, 0.47 and 0.12. Heritability estimates for 400-day weight, cow 4-year weight and cow milk yield were 0.47, 0.62 and 0.15 respectively. Genetic correlations between traits measured postweaning and the same traits measured in the cow were moderate to high, and for the feed efficiency trait, RFI, was very high (0.95), close to unity. Conclusions. Inclusion of postweaning RFI as a selection criterion in beef cattle breeding can be expected to lead to improvementin cow feed efficiency. Implications. Most breeding decisionsin beef cattle are based on traits measured early in life and forreplacement heifers are made with an aim to improve their productivity and profitability as cows. The strong and favourable associations measured between postweaning RFI and cow RFI mean that feed efficiency measured in young cattle can be used as a selection trait to improve cow feed efficiency. [ABSTRACT FROM AUTHOR]

Content. Antibiotic growth promoters (AGP) are not recommended in broiler diets due to the possible threat of microbial resistance and residues in meat. Aim. Two experiments were conducted to study the possibility of utilising coated sodium butyrate (CSB) as an alternative to AGP (500 g/t) in broiler (1-42 days) chicken diet. Method. In Experiment 1, a positive control (PC with AGP), a negative control (NC, without AGP) and CSB diet (150 g/t), and in Experiment 2, four diets, i.e. PC, NC, and CSB at two concentrations (75 and 150 g/t) were prepared. Each diet was offered ad libitum to 10 floor pens (25 broilers) with built up litter as bedding material. Key results. Bodyweight gain (BWG) and feed intake (FI) were not affected, while feed efficiency (FE) at both Day 21 and Day 42 reduced in broilers fed the NC compared with those in the AGP-fed group (Experiment 1). Inclusion of CSB (150 g/t) improved the FE similar to the AGP group. In Experiment 2, BWG and FI were not affected, while FE improved in CSB groups compared with the AGP or NC. The colony count of E. coli and C. perfringes increased in the NC group compared with the AGP group and the count in CSB groups was similar to that in the AGP group. The ileal digestibility of nitrogen (CSB150 g) and energy (CSB75 and CSB150 g) and tibia variables(total ash and breaking strength)reduced in the NC group compared with the AGP groups and supplementation of CSB improved all these parameterssimilarto the AGP group. Conclusions. On the basis of the data, it is concluded that CSB (75 or 150 g/t) can be used as an alternative to the AGP (bacitracin methylene disalysilate) in broiler chicken diet. The improvement in broiler performance with CSB in diet could be attributed to the increased ileal digestibility of nitrogen and energy, bone mineralisation and reduction in pathogenic bacterial count (E. coli and C. perfringes) in the gut. Implications. Use of AGP in broiler diets can be avoided with inclusion of coated butyric acid, without affecting the broiler performance. [ABSTRACT FROM AUTHOR]

Context. Selenium is an essential trace micronutrient that plays an important biological role in maintenance of animal health. Aims. The purpose of this study was to compare the effects of dietary supplementation of selenium (Se)-enriched yeast (SeY), Se-chitosan (SeCh), and selenised glucose (SeGlu) as organic forms of Se, as well asthe interaction of these compounds with probiotics, on broiler chicken growth, carcass characteristics, meat quality, andmeat Se concentration. Methods. In total, 300 1-day-old Ross 308 broiler chickens were randomly assigned to six experimental groupsin a 3 × 2 factorial treatment arrangement. Factorstested included Se sources(SeY, SeCh, and SeGlu at a concentration of 0.3 mg/kg) and probiotics (a mixture of probiotic bacteria containing Bacillus coagulans, Bacillus subtilis, Bacillus lichen formis, Lactobacillus faecium, Lactobacillus rhamnosus, and Lactobacillus plantarum, at concentrations of 0 and 100 mg/kg). The treatments were replicated in five floor pens, with 10 broiler chickens per pen. Key results. For the entire period (1-42 days), broiler chickens given SeCh or SeGlu showed a lower feed conversion ratio than did broiler chickens fed SeY (P < 0.05). Furthermore, broiler chickens fed diets supplemented with SeGlu without or with probiotics had considerably higher breast relative weight than did those fed SeY without probiotics. In comparison to SeY-fed birds, those fed SeCh or SeGlu had lowerthiobarbituric acid-reactive substances, drip loss, cooking loss, and higher water-holding capacity values in the breast muscle (P < 0.05). Birds fed diets supplemented with SeCh and SeGlu with probiotics had higher yellowness and lower thiobarbituric acid-reactive substances and cooking loss in breast meat than did birds fed diets supplemented with SeY without or with probiotics. Furthermore, the concentration of Se in meat was higher in birds fed a SeGlu diet with probiotics than in other treatments, except in birds fed a SeCh diet with probiotics. Conclusions. Compared to the use of SeY, the use of SeCh and SeGlu as new Se forms is a simple, unique, and cost-effective technique for improving broiler chicken growth performance, carcass characteristics, and meat quality. Implications. These findings provide a basis for the application of SeCh and SeGlu in chicken broiler diets. [ABSTRACT FROM AUTHOR]

Context. Mitigating urinary nitrogen (N) losses is an important target of sustainable cattle nutrition concepts. One option to achieve this may be dietary inclusion of tanniferous herbs. Aims. Aim of the study was to investigate herbs with different profiles of tannins for their efficiency to abate urinary N losses. Small burnet (Sanguisorba minor) with high concentrations of total tannins, plantain (Plantago lanceolata) with low concentrations and birdsfoot trefoil (Lotus corniculatus) with expectedly high concentrations of condensed tannins were included in the treatments. Methods. The test plants were mixed in dried form into a grass-maize-silage diet at 80 g/kg of dietary dry matter. They replaced dried perennial ryegrass (control). Twenty-four multiparous dairy cows were randomly allocated to the four diets. Intake, eating time, rumination time, and milk yield were recorded individually, and representative samples of milk and excreta were collected and analysed six times within 14 days, following 10 days of adaptation. The diets with ryegrass, birdsfoot trefoil, plantain or burnet contained, per kilogram of dry matter, 0, 1.8, 1.2 and 1.9 g condensed tannins, 0.1, 1.9, 1.7 and 15.5 g total tannins, and 26.2, 28.5, 27.5 and 26.6 g N. Key results. Milk yield and composition were not affected by treatment, apart from a decline in milk protein content when feeding plantain. Milk urea concentration was reduced with burnet by more than 30%, compared with the control and plantain. Birdsfoot trefoil also reduced milk urea concentration, but to a lesser degree. Furthermore, the burnet treatment substantially shifted N excretion from urine to faeces (about 30% lower urine N losses). All treatments lowered the proportion of fine particles of <1.0 mm in faeces, what might be due to high fibre content of the control. Conclusions. At dietary proportion of 80 g/kg, burnet is a forage herb with potential to reduce ruminal ammonia generation as indicated by reduced urinary N and milk urea. Plantain and birdsfoot trefoil had no or negligible effects. Implications. The study indicated that small burnet could have potential as a feed additive for dairy cows in terms of N-use efficiency, lower emissionsto the environment, and reduced animal metabolic stress. [ABSTRACT FROM AUTHOR]

Progress towards methane (CH4) mitigation for the red meat, milk and wool sectors in Australia and reduced CH4 emissions intensity (g CH4/kg animal product, typically milk orliveweight gain) involves not only reduced net emissions but also improved productive efficiency. Although nutritional additives have potential to reduce CH4 production rate of livestock (g CH4/head.day), systemic improvement of the nutrition of grazing breeding females, the largest source of CH4 emissions in Australian agriculture, will also be required to reduce emissions intensity. Systemic changes that increase productive efficiency for producers are part of the economic and environmental 'win-win' of reducing emissions intensity, and so offer good potential for adoption by industry. For sheep and cattle breeding enterprises, improved nutrition to achieve a younger age at first joining and increased reproductive rate will reduce the proportion of CH4-emitting, but unproductive, animals in a herd. However, if breeding stock are managed to be more productive (e.g. by superior nutrition leading to greater product/breeder) and more efficient (e.g. greater product per kilogram DMI) the producer is faced with the following management challenge. Should the enterprise increase stock numbers to utilise surplus feed and gain extra product, or reduce stock numbers to maintain previous product output with smaller enterprise net emissions(and emissionsintensity), and so make land available for other uses (e.g. tree plantings, conservation zones). The right balance of incentives and price on carbon is necessary to achieve a result whereby total emissions from Australian agriculture are reduced, and so a positive impact on climate change is achieved. [ABSTRACT FROM AUTHOR]

Context. Identification earlier in life of beef cattle with capacity for increased marbling, improved carcase yield and/or reduced subcutaneous fatness can facilitate more rapid genetic improvement and identification of cattle more appropriate forfeedlot or pasture finishing. Earlierin life, ultrasound predictions have potential for significant improvements in compliance with market specifications and overall efficiency of beef production systems. Aims. To assess the relationships just prior to slaughter and earlier in life between measurements of intramuscular fat, subcutaneous fat and eye-muscle (Longissimus thoracis et lumborum) cross-sectional area made using ultrasound, and carcase fatness, muscling and yield measurements following slaughter of Bos taurus steers that differed genetically in potential for subcutaneous fatness and marbling. Methods. Ultrasound measurements of intramuscularfat (IMF), rib fat (RFT), P8 rump fat (P8FAT), eye-muscle area (EMA) and retail beef yield (RBY) of cattle heterogeneous for marbling and fat distribution were made at six stages of growth from weaning to long-feedlotting. Carcase measurements of the same traits were made at five stages of growth from weaning through to long-feedlotting. Key results. IMF ultrasound scans 168 days post-weaning were more strongly correlated (r = 0.79) with marbling in the carcase following long-feedlotting than were IMF ultrasound scans at the end of backgrounding (r = 0.71, 326 days post-weaning), short-feedlotting (r = 0.69, 431 days) and during (r = 0.59, 521 days) and at the end of long-feedlotting (r = 0.53, 585 days). P8FAT was the trait with the highest and most consistent accuracy across all stages of life (r = 0.80) between ultrasound and carcase measurements of P8FAT. Conclusions. The results of the present study showed that ultrasound-scanned measures of carcase IMF, subcutaneous fat and EMA can be used to predict carcase characteristics with good accuracy earlier in life. Implications. The finding that prediction of marbling in the carcase of long-feedlot-fed cattle was stronger by using ultrasound measurement of IMF in younger post-weaned cattle than in older post-weaned cattle warrants further investigation for genetic improvement and management applications, including using newer scanning technologies. [ABSTRACT FROM AUTHOR]

Context. Developing strategies to reduce carcass fatness is vital to the profitability of animal production, particularly in a market where excessive backfat causes price penalties. Studies have shown that betaine supplementation has inconsistent effects on carcass fatness, which are due in part to variability in the betaine dose, duration of supplementation and growth state. Grower pigs have a greater lean:fat deposition ratio than do finisher pigs and are more sensitive to anabolic stimuli. The betaine-spared energy may be deposited as more lean tissue when betaine is supplemented during the grower phase. We hypothesised that 0.1% betaine supplementation within the grower phase is more effective in reducing carcass backfat than is supplementing in the finisher phase. Such an effect may also interact with sex. Aims. The objective was to optimise betaine supplementation duration to reduce carcass backfat thickness of finisher pigs. Methods. Eighty pens of pigs (39 pigs/pen) were allocated to a 2 × 2 × 2 factorial arrangement on the basis of sex (immunocastrated male vs female pigs), betaine supplementation (0 vs 0.1%) during the grower phase (10-16 weeks of age) and the finisher phase (16 weeks of age to approximately 22 weeks of age). Growth performance, carcass weight and backfat thickness were recorded. Key results. Betaine supplementation during the grower phase or finisher phase reduced backfat thickness in female pigs by 0.7 mm and 0.5 mm respectively. But the effect in reducing female backfat diminished when the supplementation extended to both grower and finisher phases. No such effect was found in immunocastrated male pigs (grower phase diet × finisher phase diet × sex, P < 0.05). Betaine supplementation during the finisher phase reduced growth rate by 40 g per day, regardless of sex (finisher phase diet, P < 0.05). Conclusions. The effect of betaine in reducing carcass backfat was observed in female pigs only. Additionally, this occurred only when betaine was supplemented for 6 weeks in either the grower or finisher period, with supplementation for the 12-week period negating the effect. Implications. The effectiveness of betaine supplementation in reducing carcass backfat is sex and duration dependent. [ABSTRACT FROM AUTHOR]

Context. Among the by-products derived from oilseeds, palm kernel cake (PKC) contains high concentrations of protein, fat, and fibre, which allows some flexibility in the use of this ingredient in ruminant diets. Aim. This study examined the effects of including palm kernel cake (PKC) in high-grain diets for cull cows on production performance, carcass traits, and meat fatty acid profile. Methods. Thirty-six ½ Girolando cows at 83 ± 5 months of age, with an average liveweight of 384.88 kg ± 59.18, were confined in collective stalls for 90 days. The animals were distributed into the following four diet groups: 0% (control), 8%, 16%, or 24% inclusion of PKC in the diet dry matter (DM). Key results. On the basis of regression analysis, the highest slaughter weight and carcass weight were at PKC inclusion levels of 11.5% and 10.3% respectively. Backfat thickness was greatest (8.8 mm, P < 0.01) in the carcasses of cows fed the diet with 15.1% PKC (on the basis of regression analysis), whereas the total lipid content in the meat decreased linearly (P < 0.05) with PKC inclusion. The C10:0, C12:0, C14:0, C14:1, C16:0, C16:1, C17:1, C18:0, C18:2n6t, and C20:5n3 fatty acids in the longissimus thoracis muscle responded quadratically (P < 0.05) to the inclusion of PKC. The highest concentration of desirable fatty acids was obtained with the inclusion of 11% PKC in the diet (on the basis of regression analysis). There was a linear increase in C14:1, C20:2, and C22:2 fatty acids and Δ9 desaturase 14 and 16 activity indices in the muscle of cows fed PKC. Conclusion. We recommend the inclusion of 10% PKC in the diet of cull cows fed high-grain diets. Intramuscular fatty-acid proportions were appreciably different from those reported for young B. taurus steers and heifers finished on high-concentrate diets. Implications. Therefore, inclusion of PKC is an excellent alternative to reduce production costs, having the availability and quality of the product as a limiting factor, since PKC is an industrial by-product. [ABSTRACT FROM AUTHOR]

Context. Globally, sheep productivity is constrained by scarcity of high-quality feed and haemonchosis. These challenges may simultaneously be addressed by valorisation of nutraceutical forage legumes such as sericea lespedeza (SL) into sheep diets. Aim. The current study determined the effects of feeding diets containing increasing inclusion levels of SL (0%, 6.25%, 12.5%, 18.75% and 25%) as replacement for lucerne on haematological, biochemical, and parasitological parameters in Haemonchus contortus-infected and non-infected lambs. Methods. Bodyweights, body condition scores (BCS), FAMACHA© scores, faecal worm egg counts (FWEC), and haematological and biochemical parameters were recorded from 80 Dohne Merino intact male lambs assigned to diet-by-infection status-based treatments in a completely randomised design, with a 5 × 2 factorial arrangement of treatments comprising of eight lambs pertreatment during a 42-day feeding trial. Adult worms were collected, enumerated, and their ultra-structure was evaluated using scanning electron microscopy after slaughter. Results. Diet, and diet × infection status had no effects on red blood-cell parameters of the lambs (P > 0.05). Eosinophils were affected by diet × infection status, being highest in non-infected lambs fed the control diet and lowest in infected lambs fed the 25% SL diet (P = 0.05). Serum albumin, calcium and body condition scores declined (P = 0.05) with increasing inclusion levels of SL in the diet. There was no influence of diet on lamb bodyweights, FAMACHA© scores, FWEC, and worm burdens. Dietary increments of SL disrupted the structural integrity of the head (Χ² = 28.43; ɸc = 0.493; P = 0.05) of adult worms. Conclusions. Sericea lespedeza may replace lucerne up to 25% in lamb feedlot diets, with minor negative effects on haematological and biochemical parameters, but offers little benefits for modulating Haemonchus contortus infection. Implications. Beneficiation of biologically active alternative feed resources such as sericea lespedeza could help farmers adapt better to market changes through the development of enhanced livestock feed and pharmaceutical products, which could help alleviate losses associated with impoverished nutrition and gastrointestinal health of lambs. [ABSTRACT FROM AUTHOR]

Context. Utilising crop residues is an effective strategy to compensate for the shortage of common feed resources. Different processing methods can improve the nutritional value of these by-products. Aims. This study aimed to investigate the effect of sodium hydroxide (NaOH, 50 g/kg dry matter (DM)), calcium oxide (CaO, 160 g/kg DM), hydrobromic acid (HBr, 60 mL/kg DM), and hydrogen peroxide (H2O2, 57 mL/kg DM) processing on the nutritional value of common bean (Phaseolus vulgaris) residues (CBR). Methods. The chemical composition of the samples was determined using standard methods. In addition, a degradability trial was conducted using the nylon-bag technique. Furthermore, in vitro digestibility of the samples was determined by the batch-culture method. Moreover, the X-ray powder diffraction technique was used to calculate the crystallinity degree of the samples. Key results. Chemical processing was effective on the chemical composition of the residues (P < 0.05). Treatments of CaO, H2O2, and NaOH increased the ash content. Chemicals reduced the neutral detergent fibre and acid detergent fibre. Other treatments, excluding CaO, increased total digestible nutrients, net energy for lactation, and net energy for gain. NaOH, H2O2 and HBr treatments increased the effective ruminal degradability of DM at ruminal outflow rates of 0.02, 0.05, and 0.08/h (P < 0.0001). Chemical processing caused a decrease in gas production (GP) and estimated parameters of CBR (P < 0.0001). The decrease in GP, short-chain fatty acids, metabolisable energy, and organic-matter digestibility in the NaOH and CaO treatments was more than in HBr and H2O2 treatments. After 24 h of incubation, all treatments except CaO increased the partitioning factor and decreased the gas yield (P < 0.0001). Furthermore, processing with NaOH and H2O2 increased the microbial biomass (P = 0.0128) and its efficiency (P < 0.0001) at the end of a 24 h incubation period. Moreover, different treatments reduced the crystallinity degree of CBR compared with the control. Notably, the lowest crystallinity percentage was observed in HBr-treated samples. Conclusions. This study shows that chemical treatments (except for CaO) improve CBR nutritional value under in vitro and in situ conditions. Implications. In vivo tests are required to validate the results. [ABSTRACT FROM AUTHOR]

Context. Soxhlet extraction is commonly used for determining fat content of meat, because it isthe basis of the AOAC Final Action method for this analysis. Petroleum ether is used as an extraction solvent but other solvents, such as chloroform, can be used. Chloroform has been stated to be a safer solvent than petroleum ether and is used extensively for Soxhlet extraction for meat research in Australia; yet, there has been no report that validates its use for this purpose. Aim. To compare the use of chloroform with that of petroleum ether as an extraction solvent for Soxhlet fat extraction in beef. Methods. The fat content ofsix beefsamples, reported as chemical lean (CL, 100 - %fat), was determined using Soxhletfat extraction with chloroform (by two independentresearch providers) and petroleum ether (b.p. 40-60°C, using three commercial providers). Passing-Bablok regression and Bland-Altman plot analysis were used to identify any differences and bias between the methods respectively. Key results. Passing-Bablok regression showed that there was no difference between the use of chloroform and the use of petroleum ether as a solvent for Soxhlet fat extraction in beef. Bland-Altman plot analysis indicated that there was no bias evident between the uses of each solvent. Thus, this would indicate that chloroform can be used as a solvent for Soxhlet fat extraction, providing equivalency to petroleum ether. While some minor differences were apparent, this is most likely attributable to sample heterogeneity. Conclusions. Chloroform was found to provide equivalency to petroleum ether for fat extraction from meat. While some minor differences were apparent in the fat content of meat, this has been attributed to likely sample heterogeneity. Implications. Chloroform can be used as an extraction solvent for Soxhlet fat extraction of beef. [ABSTRACT FROM AUTHOR]

Context. There are still comparatively few methods for the detection of drug residues in buffalo milk. Aims. This study aims to develop a method for the detection of drug residues in buffalo milk. Methods. In this study, we developed an analytical method for veterinary drug residues in buffalo milk using liquid chromatography-tandem mass spectrometry. The multi-residue method was established for the simultaneous identification and quantitation of eight common veterinary drugs, including metronidazole, salbutamol, atropine, trimethoprim, hydrocortisone, kitasamycin, roxithromycin and tylosin. Key results. The sample processing method for buffalo milk was compared and optimised. The precision, recovery and matrix effects of the method were validated. The precision and accuracy of all analytes ranged from 1.81% to 12.35% and 1.25% to 14.57%, respectively. The average recovery percentages varied between 93.59% and 114.57%, and the average matrix effect ranged from 87.12% to 103.76%. All eight analytes in buffalo milk exhibited stability under different treatment conditions. Conclusions. The developed method was successfully applied to laboratory analysis and routine sample analysis. The method was demonstrated to be rapid, sensitive and reliable for the rapid monitoring of veterinary drug residues in buffalo milk. Implications. The findings of this study contribute to the risk assessment of veterinary drug residues for preventing the human consumption of contaminated buffalo milk and its derivatives. [ABSTRACT FROM AUTHOR]

Context. The introduction of bio-sensors for monitoring real-time changes in physiological variables has helped understand how external factors affect an animal's resiliency to stressors. Aims. To quantify changes in temperature, heartrate, and locomotor activity in ewes during hormonal treatments for artificial insemination (AI) for up to 15 days after insemination. Method. Twelve ewes received a surgically implanted subcutaneous bio-loggerto record data every 5 min. One week later, ewes received an intravaginal sponge for 12 days and AI was performed 54 ± 1 h after sponge withdrawal. The data were divided into the following four periods: 'sponge in' (Days -14 to -2), 'day before AI' (Day -1), 'day AI' (Day 0), and 'post-AI' (Days 1-5, Days 6-10, and Days 11-15). Key results. Ewes presented significantly (P < 0.001) higher mean temperature and activity, and a lower heart rate when the sponges were in place than they did in the days following AI. Mean body temperature in the 'sponge in' period and the 'day before AI', but not in 'post-AI period', differed significantly (P < 0.001) between pregnant and non-pregnant ewes. Non-pregnant ewes had a significantly (P < 0.001) higher heart rate than did pregnant ewes when sponges were in and in the 'post-AI' period. Non-pregnant ewes were significantly (P < 0.001) less active than were pregnant ewes in the 'sponge in' period and on Days 1-5 after AI; however, the former were significantly (P < 0.001) more active than were pregnant ewes on Days 11-15 after AI. Conclusions. The subcutaneous bio-logger system documented 24-h variations in body temperature, heart rate, and locomotor activity before and after AI in ewes that had received an estrus-synchronising hormonal treatment. Pregnancy status affected those variables and their circadian fluctuations at the time of the hormonal treatment and in the 'post-AI' period. Implications. Any device designed for use in the study of Precision Livestock Farming that allows a simple, non-invasive measurement of these variables might provide the basis for the development of a system that could identify females that are in an optimal state for insemination, and provide an early pregnancy prediction system. [ABSTRACT FROM AUTHOR]

Context: The complexity in swine production demands equally complex management actions. In this sense, risk management is an area that has been little explored and that may offer significant contributions to pork producers in their decision-making processes. Aims: This study aimed to collect the available information on risks in pig farming and identify how the topic has been approached in recent studies. Methods: A systematic review was conducted on the basis of searches in the Web of Science , Scopus and Science Direct databases, in the period ranging from 2015 to 2021. The searches resulted in 2178 documents on the theme risks in pig farming, which were then classified into 13 categories to represent the general objective of each study and into 177 subcategories representing the specific objective of each work. The data, separated into categories and subcategories, was not classified by any exclusionary criteria. On the contrary, they represent all the information found in the studied documents. Key results: The results show that, although the number of studies on risks in pig farming is growing, the studies are contained in specific fields only. It was also possible to observe that although the studies focused on problems that may affect pig raising, they were not approached in a holistic manner using risk management methodologies that would allow identifying, measuring and managing risks in a consistent and systematic way. Thus, the studies cannot be characterised as having a risk management approach. Conclusion: The studies on risks in pig farming focus on specific areas instead of using an integrated approach. It was found that risks in pig farming are a growing concern, but a holistic approach to the subject is still unexplored and could be quite fruitful, as it would make it possible to identify, measure and manage risks in a more consistent and systematic way. Implications: Producers, veterinarians, managers and researchers can use the results of this study (1) to develop identification systems, and (2) in quantitative and qualitative analyses, planning, implementation of responses and monitoring of risks in pig farming. The complexity in swine production demands management actions that are equally complex. An area that may significantly help pork producers with their decision-making is risk management. A systematic review was carried. The searches resulted in 2178 documents on the theme risks in pig farming. The results showed that risk is a growing theme in the area but they were not approached in a holistic manner through specific methodologies that would allow identifying, measuring and managing risks in a consistent and systematic way and thus be characterised as risk management. [ABSTRACT FROM AUTHOR]

Context: Plasma fatty acid profiles provide evidence of short-term feeding, while red blood cells (RBC) indicate longer-term feeding effects. Information on the rate of change in fatty acid profiles of sheep blood over time after alterations in diet is lacking. This study monitored the short- and longer-term effects of feeding grain-based diets to lambs on changes to omega-3 polyunsaturated fatty acids (PUFA) in blood fractions over 21 days. The data provide a guide to managing omega-3 PUFA availability for adequate tissue accretion of these fatty acids. Aims: To determine the rate of depletion over 21 days of omega-3 PUFA in the blood fractions of sheep fed on grain-based diets. Methods: Blood samples were taken from ewes taken off pasture and fed grain-based diets for 21 days. Fatty acid profiles in the blood plasma and RBC were used to monitor the rate of depletion of omega-3 PUFA. Key results: Immediate changes in plasma omega-3 PUFA concentrations occurred from the first day of grain feeding. The omega-3 PUFA content declined continuously on all five grains, but with substantial differences among them. RBC omega-3 PUFA contents displayed great variation across individual sheep but depletion was not significant. Conclusions: Plasma omega-3 PUFA depletion immediately on grain feeding indicated a lower availability for tissue accretion in growing sheep following short-term changes in diet. The lack of change in RBC omega-3 PUFA concentrations over 21 days indicated a differential accumulation of these fatty acids in this lipid depot compared with plasma, and changes in other tissues should also be examined. Implications: The effect of these short- and long-term changes on LC n -3PUFA accumulation in meat and reproductive tissues warrants further investigation. Omega-3 fatty acids can have important health implications and are associated with altered reproductive efficiency in sheep. The rate of depletion of omega-3 with different grain types was previously unknown; however, results from the current study showed that depletion is similar with oats, wheat, lupins and barley, although some changes in red blood cells were not as great for barley compared with other grains. The effect of these changes on fatty acid concentrations in meat and reproductive outcomes should be investigated further. [ABSTRACT FROM AUTHOR]

Context: Reducing livestock emissions, the largest single contributor to agricultural emissions, is increasingly recognised as a high priority. The low biological efficiency of beef cattle, due to their long gestation period, long generational interval, and propensity to be uniparous, contributes to the high methane emissions intensity (kg CO2-e/kg product) of beef compared to most other food products. Aims: We evaluate the potential of increasing the frequency of multiparous births (twinning) as a pathway to reducing the methane intensity of beef and the net methane emissions of intensive beef systems. Methods: We simulate a uniparous herd structure and emissions profile using GrassGro™ livestock systems modelling software and then calculate the effects of an increasing frequency of multiparous births (twinning), up to 1.53 calves per cow joined, on methane emissions. Key results: Our results demonstrate that beef from calves reared as twins has a 22% lower methane intensity than beef from a single reared calf. Although twinning reduces the methane intensity of beef, at the herd level, net methane emissions could rise by as much as 23% at 1.53 calves per cow joined if overall herd size is allowed to grow through an increased number of calves. If we decrease stocking rates, whilst also increasing twinning rates, it is possible to reduce net emissions by up to 14%, without changing productivity. Conclusions: Our results illustrate the significant potential of twinning to decrease the methane intensity of beef and to increase the productivity per cow in intensive beef systems. Implications: Despite this, twinning is unlikely to be a viable net emissions reduction pathway – as twinning will increase stocking rate unless herd structure is altered – unless a commercial or policy driver to reduce net methane emissions is established. Beef has a high emissions intensity due in part to the low reproductive rate of cattle. We evaluated if increasing the rate of twinning offers a pathway to reducing the methane intensity of beef by increasing biological efficiency, our results show that beef from twin reared calves has a 22% lower methane intensity. However, twinning is unlikely to be a viable net emissions reduction pathway unless a commercial or policy driver to reduce net methane emissions is established. [ABSTRACT FROM AUTHOR]

Context: Shading reduces forage mass and can reduce animal production and profitability per area in silvopastoral systems (SPSs) with tropical grasses. This reduction in profitability is the main obstacle to using such systems. Aims: This study evaluated the effects of shading by different tree arrangements on tropical grass characteristics and cattle performance in SPSs. Methods: Systematic searches were conducted in databases and directly in scientific journals, and 66 articles were selected. Data were grouped into SPS subgroups on the basis of tree type: with Eucalyptus with 1–14 m between rows; with Eucalyptus with 15–28 m between rows; with Eucalyptus with more than 28 m between rows; with leguminous trees; with palm trees; and with other types of tree. Data were analysed with random-effects model by using mean difference with 95% confidence interval (at P = 0.05). Results: A large reduction in forage mass significantly reduced animal weight gain per area and stocking rate of beef cattle reared in SPSs with row spacing of up to 28 m, compared with pasture monoculture. There was a small reduction in forage mass in SPSs with Eucalyptus with more than 28 m between rows, compared with pasture monoculture, but no reduction in stocking rate. This result allowed an increase in weight gain per area and indicated the need to use more than 28 m between Eucalyptus rows in systems the main objective of which is animal production. There was also a small reduction in forage mass in leguminous tree SPSs, but weight gain per area was similar to that in pasture monoculture; the animals also had a higher dry-matter intake, crude protein intake and milk production in these SPSs. The tropical grasses in palm tree SPSs had a higher crude protein and a lower forage mass than did those in pasture monoculture, and no reduction in weight gain per area compared with those in pasture monoculture, which indicated the possibility of productive animal production together with palm trees. The SPSs with other types of tree had a higher weight gain per area than did pasture monoculture. This result indicated that the use of SPSs with native trees can integrate animal production with environmental preservation. Conclusions: The SPSs with Eucalyptus with more than 28 m between the rows or with other types of tree had a higher weight gain per area than did pasture monoculture, whereas leguminous and palm tree SPSs had a weight gain per area similar to that of pasture monoculture, which indicated that there was no significant negative effect of shading on livestock production. Implications: Silvopastoral systems with higher weight gain per leaf area than, or similar to that of pasture monoculture can increase the total system production and profitability (considering wood and animal productions), which is beneficial and may be a factor in motivating producers to adopt these SPSs on commercial farms. Silvopastoral systems (SPSs) are recognised for good production and environmental indicators, but excessive shading and competition for water in the systems with a high tree density reduces forage mass and can reduce animal production and profitability. We performed a meta-analysis with studies in tropical climates and observed that in SPSs with Eucalyptus with more than 28 m between the rows, and with leguminous or with palm trees, the animal performance was similar to that of monoculture pasture. The results showed an increase in the total production of the system, which may encourage implementation of SPSs on commercial farms. [ABSTRACT FROM AUTHOR]

Context. In grazed grassland, the per area output of animal-source products usually declines with decreasing stocking rates because of lower herbage utilisation efficiency. Consequently, nutrient export is larger with increased stocking intensity, which should decrease the productivity in the long term. However, little information is available on long-term productivity of extensive grasslands under varied stocking intensities receiving no input. Aims. The effect of stocking intensity was investigated in a long-term grazing trial over 16 years of production. We hypothesised that, despite minimal nutrient export under grazing, no reduction in productivity occurs over long-term periods, but expected an interaction between stocking intensity and year. Method. The net pasture productivity was determined in terms of animal performance assessed from Fleckvieh cows grazing in a randomised block design with three replicates in three different stocking intensities (moderate, lenient, and very lenient, corresponding to stocking rates of I.I, 0.7, and 0.5 livestock unit/ha.year respectively), recorded from 2005 to 2020. Metabolisable energy in GJ/ha.year (MEtotal) provided by the pasture and the livestock unit grazing days/ha.year (LUGD, I LU = 500 kg) were calculated on the basis of liveweight measurements. Key results. The interaction of year and treatment significantly affected LUGD (F = 16.85, d.f. = 30, P < 0.0001) and MEtotal (F = 12.81, d.f. = 30, P < 0.0001) and indicated a cyclic trajectory with increases and decreases in performance over the study years. Overall, the moderate stocking intensity led to and maintained significantly higher performance than did very lenient grazing of up to 60% and 55% in LUGD and MEtotal respectively. However, structural equation modelling indicated a negative temporal trend irrespective of stocking intensity. Conclusions. On the basis of existing data of herbage quality and botanical composition from the same experiment, this trend was likely to be a result of nutrient redistribution within pastures that probably changed the botanical composition and grass sward productivity in conjunction with drier years towards the end of this study period. Implications. This study showed that productivity in low-input grassland under continuous grazing declines over time irrespective of stocking intensity. Productivity decline in all treatments implies tradeoffs forfarmers grazing at lower stocking intensities. [ABSTRACT FROM AUTHOR]

Context. The need for the storage of fertile eggs is a reality in the poultry industry. At the same time, prolonged storage periods decrease the quality of egg components that are essential for embryo development, and can compromise hatchability and chick quality; thus, the high content of unsaturated fatty acids in embryo tissues increase the susceptibility to peroxidation. Aims. The objective of this study was to evaluate the addition of ris-9, trans-11, trans-10 and ris-12 isomers of conjugated linoleic acid (CLA) to the broiler-breeder diet and the storage time on the internal egg quality, composition and lipid oxidation. Methods. In total, 22 000 Cobb female broiler breeders of 58 weeks of age were fed with diets containing 0 or 0.024% CLA and fertile eggs were stored 3, 6 or 9 days prior to incubation. In total, 6912 hatching eggs were used in a completely randomised experimental design in a 2 X 3 factorial arrangement (CLA inclusion X egg storage time). At the end of each storage period, 30 eggs per dietary treatment were sampled to analyse yolk and albumen height, percentage and pH, yolk:albumen ratio, yolk diameter and index, Haugh unit (HU), yolk lipid oxidation, acidity and fatty acid profile. Key results. The progression of storage negatively affected the internal quality of the eggs; however, inclusion of CLA minimised these effects up to Day 6, especially for yolk diameter, HU, height and albumen pH. The total lipid content was not affected by the dietary treatments; however, CLA inclusion resulted in a higher proportion of stearic acid and a lower concentration of linoleic acid in yolks. Conclusions. The changes observed in fatty acid profile of the eggs may have favoured the reduction of lipid oxidation, as shown by the decrease in the acidity index and thiobarbituric acid-reactive substance (TBARS) values at shorter storage periods. Implications. The dietary addition of CLA to broiler breeders may be used to preserve the egg internal quality during a short-term storage period. [ABSTRACT FROM AUTHOR]

Context. Our previous study revealed that micronised bamboo powder (MBP) can promote the growth performance of broilers aged 1-22 days by improving oxidation resistance, balancing intestinal microflora and regulating metabolic pathways. Aims. This study evaluates the effects of MBP on growth performance, intestinal development, caecal chyme microflora and metabolic pathways of broilers during the grower period, age 24-45 days. Methods. Slow-growing spotted-brown broilers (n = 880, age 24 days) were randomly divided into two groups according to weight and sex and fed either a maize-based diet (control) or a diet with MBP at 1% replacing equivalent maize. Key results. No significant difference was observed in growth performance between MBP and control groups. Broilers receiving MBP exhibited significantly higher (P < 0.05) caecal organ index, jejunum villus height and villi:crypt ratio. The relative abundance of Firmicutes was higher, and relative abundance of Bacteroidetes was lower in the MBP group. Addition of MBP also significantly (P < 0.05) upregulated abundance of p_Firmicutes, f_Alicyclobacillaceae, g_Acutalibacter, f_Peptococcaceae, f_Clostridiaceae, f_Bacillaceae, g_Enterococcus and f_Enterococcaceae, while downregulating abundance of p_Bacteroidetes, f_Bacteroidaceae, g_Bacteroides, o_Bacteroidales and c_Bacteroidia. For the metabolic pathways, 66 were observed to differ between dietary groups, including alanine, aspartic acid and glutamic acid metabolism, butyric acid metabolism, arginine synthesis, linoleic acid metabolism and ^-alanine metabolism. Correlation analysis revealed that Firmicutes in caecal chyme were significantly positively correlated (P < 0.05) with some fatty acids including syringic, 3-methyl-2-oxovaleric, 3-(2-hydroxyphenyl) propanoic and butyric acids. Bacteroidetes were positively correlated (P < 0.05) with some amino acids including L-alanine, L-threonine, 3-methylthiopropionic acid and L-glutamic acid. Conclusions. Replacing maize with MBP at 1% had no negative effect on growth performance of broilers. Feeding MBP improved intestinal development and increased the relative abundance of bacteria that promotes fatty acid metabolism and fibre degradation. Implications. MBP provides an alternative to maize and is a beneficial source of fibre; further research is warranted to determine the optimum feeding level. [ABSTRACT FROM AUTHOR]

This review presents a new model for a multidisciplinary approach to development of modern forage cultivars to enable high-value meat and wool production in the mixed farming zones of Australia. Many pasture improvement activities focus on biomass production, filling novel agro-ecological niches, fixing nitrogen and phenotypic markers. Key traits that drive profitability of livestock, such as feeding value (FV), and nutritive value (NV), are rarely considered in a timely manner. Farmers are often not seriously engaged until late in the development pipeline. Of the nearly 10 000 publications that reference forage improvement or breeding and Australia, less than 5% also reference ruminant production factors such as FV, metabolisable energy, digestibility, methane or toxicity in the abstract, title or keywords. We make the case that the late engagement of livestock science and farmers results in early discarding of potentially valuable genetic material. This in turn may contribute to market and nutritional limitations that contribute to the high failure rate of new pasture cultivars. Four case studies demonstrated the within and among species variation in FV and NV. The first showed the variability in dry matter digestibility and crude protein of 20 species of herbaceous perennials at different stages of maturity. A second study with annual legumes, grasses and brassicas indicated highly significant differences in the rate of decline of NV over time and across species. The third case study focused on commercial and experimental accessions of lucerne and demonstrated highly significant differences among accessions in NV, with a doubling of livestock growth expected with the lowest and highest NV accessions. These case studies demonstrated the potential risks associated with evaluation of FV and NV after most of the germplasm has been excluded. The final case study described a different model that was used in the identification and commercialisation of a woody perennial species. This process incorporated a multidisciplinary team, farmers and livestock-relevant characteristics from the start. In 9 years, Anameka™ oldman saltbush was selected for higher palatability, 20% higher organic-matter digestibility and eight times more biomass than the average of the original genetic material. [ABSTRACT FROM AUTHOR]

Context. Mating of ewe lambs can increase farm profitability, although uptake is limited by low reproductive success. Reproductive loss to Day 35 of pregnancy in peripubertal ewe lambs is greater than in adult ewes; however, the precise timing of this loss is unknown. Aim. We aimed to define more clearly early embryo development and key times of loss in peripubertal ewes. Methods. Health and development of embryos from naturally cycling crossbred ewes ~8 months of age were recorded. Following mating across 2 years, ewes were assigned to three groups (n = 80-87 per group): assessed on Day 3 of pregnancy, on Day 14, or between Day 35 and birth. For Day 3 and Day 14 groups, ewes were humanely killed, and embryos were assessed by microscope following recovery from the reproductive tract. Ultrasonography at around Days 35 and 70, and lambing data, were used to assess loss in the third group. Key results. By Day 3 of pregnancy, 22.9% of ova released were not present as healthy embryos (P < 0.05). Embryo survival on Day 14 tended (P < 0.10) to decrease further, with 34.0% (±4.5%) of ova released not present as healthy embryos. No decrease was detected between Days 14 and 35, whereas between Day 35 and birth, an additional 6.8% reproductive loss occurred (P < 0.05). Attainment of puberty prior to introduction of the fertile ram did not affect reproductive loss. Structures collected on Day 3 ranged from one cell to 12 cells: 11% (13/120) being one cell; 49% (59/120) two to four cells; and the remainder (48/120) at least five or six cells. Conceptus length at Day 14 ranged from 5.3 to 200.0 mm, with large variation between and within animals; within-ewe variation was 67% of between-ewe variation. Concentration of progesterone at time of collection was associated (P < 0.001) with developmental stage on Day 3, but not Day 14, of pregnancy. Conclusions. Reproductive loss in peripubertal ewes primarily occurred prior to Day 14, with much of this loss before Day 3. Implications. Improving oocyte and oviduct quality is important to supporting normal fertilisation and early embryo development in peripubertal ewe lambs, thus improving reproductive success. [ABSTRACT FROM AUTHOR]

Context. Climate and economic changes promote the encroachment of woody plants on marginal mountain pastures. In the Alps, the main woody invader is the nitrogen-fixing shrub Alnus viridis (green alder). Robust breeds of different ruminant species may perform well on these shrub-encroached pastures. Aims. To assess the effects of A. viridis encroachment levels of mountain pastures on the growth performance and carcass and meat characteristics of cattle and sheep. Methods. For 8-9 weeks, 22 15-month-old growing Dexter cattle and 20 7-month-old weaned Engadine sheep were grazed rotationally on pastures in a subalpine zone with four different levels of A. viridis encroachment (average: 0.8%, 28.7%, 50.3% and 67.8%). Following slaughter, the assessed carcass and meat characteristics (longissimus thoracis and biceps femoris) included physico-chemical meat quality, muscle fibre typing, fatty acid profiling (intramuscular and perirenal fat) and the sensory properties of patties. Key results. The shrub encroachment levels had only minor effects on the animals. Interactions with the animal species influenced some sensory and fatty acid characteristics. The average daily gains were 201 g in the Dexter cattle and 104 g in the Engadine sheep. Both species achieved satisfactory carcass and meat quality and favourably low n-6/n-3 fatty acid ratios (0.63 and 0.68 in the intramuscular fat of the cattle and sheep, respectively). The meat from the Dexter cattle had a slightly higher cooking loss and shear force and a slightly lower proportion of fatty acids relevant to human health. Flavour appreciation was in favour of the burgers prepared from the beef. Conclusions. Both robust breeds were suitable for producing meat on extensive pastures with A. viridis encroachment of up to 70%. Based on indirect evidence, it seems that neither species consumed significant quantities of leaves or bark from the trees. Implications. Our study provides detailed information on rare robust breeds of two animal species in the context of meat production according to customer preferences. To better explain the differences between the two animal species, particularly in terms of fatty acid profiles, the role of the A. viridis understory needs to be clarified. [ABSTRACT FROM AUTHOR]

Context. Deworming all horses with commercial anthelmintics on a rotational basis every 90 days is still popular worldwide. Aims. To investigate anthelmintic resistance and therapeutic requirements of adult horses on the basis of faecal examinations after a rotation between commercial anthelmintics commonly used in Brazil. Methods. We followed up faecal egg counts and coprocultures of 29 horses for 7 months, after pre-established anthelmintic treatments, every 3 months (August and November 2019 and February 2020). The following commercial anthelmintics were used respectively: moxidectin (1), ivermectin + praziquantel (2) and trichlorfon + mebendazole (3). Faecal egg count (FEC), FEC reduction tests (FECRT) and coproculture were performed before (Day 0) and after 14 days for each of the three treatments. Wilcoxon test (95% confidence level, P < 0.05) was used to test the efficacy of the treatment on the FECRT and the occurrence of resistance to the treatments used. Results. The FEC results and percentage of individual FECRT indicated parasite resistance, and 82 of 87 (94%) deworming treatments were unnecessary. The efficacy rate was 78%, 34% and 53% for Treatments 1, 2 and 3 respectively. In the coprocultures before deworming, 98.5% were small strongyles, 1.1% Strongylus equinus and 0.4% Gyalocephalus capitatus. After deworming, 98.7% of parasites were small strongyles and 1.3% Dictyocaulus arnfieldi. FEC values at Day 0 and 14 days after anthelminthics were different (lower) only for the moxidectin treatment (U = 271.5; P-value <0.01). For both ivermectin + praziquantel (U = 373; P-value >0.05) and mebendazole + trichlorfon (U = 391; P-value >0.05) treatments, there was no difference in FEC between Day 0 and Day 14 at 95% confidence level. Conclusions. The anthelmintics used in the deworming protocol of this study had reduced efficacy against the parasites identified in the coprocultures and the pre-established treatments were probably unnecessary in 93% of the horses with a low level of infection. Implications. This study has highlighted not only the issue of the indiscriminate use of anthelmintics regarding parasitic resistance, but also the exposure of horses to unnecessary treatments. Such widespread use is a costly waste of resources and further reinforces the discontinuation of schedule rather than strategic deworming protocols. [ABSTRACT FROM AUTHOR]

Context. Tannins are blamed for negatively affecting nutritive value of sorghum. Kafirins are sorghum storage proteins and may be associated with lower animal performance. They have been tested in poultry diets; however, information for pig diets is scarce. Aims. Our aim was to determine the role of kafirins and tannins in sorghum nutritive value for swine. Methods. Two experiments evaluated effects of sorghum tannin and kafirin levels on (I) nitrogen (N) and energy balance, and (2) performance of pigs. Two sorghum hybrids with low (LT) and high (HT) tannins were grown at two rates of N fertiliser to achieve low (LK) and high (HK) kafirins (i.e. four sorghum treatments: LTLK, LTHK, HTLK and HTHK) and added to soybean meal based diets. A fifth diet included maize instead of sorghum. Five pigs (48.8 ± 0.4 kg) were used in a 5 X 5 Latin square design to measure N and energy balance, with 5 days of diet adaptation and 4 days of urine and faeces collection. The performance experiment included 60 pigs (54.0 ± 12.4 kg, 30 barrows and 30 gilts, six of each per treatment) placed in individual pens with free access to water and feed. Key results. Energy balance showed a tannin X kafirin interaction (P < 0.05) for dry matter feed intake, which diminished with the LTHK diet and was unaffected with the HTHK diet. Dry matter digestibility was higher (P < 0.001) with maize, intermediate with LT, and lower with HT diets. Pigs fed maize retained more N (P < 0.05) and had higher energy digestibility (P < 0.001) than pigs fed sorghum. HT diets had lower (P < 0.01) energy digestibility than LT diets. In the finishing phase, average daily feed intake showed a tannin X kafirin interaction (P < 0.05); pigs fed the HTHK diet had lower average daily feed intake than other pigs. This lowered average daily liveweight gain and consequently final weight. Conclusions. Tannins negatively affected sorghum nutritive value; high kafirins worsened average daily feed intake and liveweight gain, and hence final weight. Implications. Management of kafirin content should be considered to avoid adverse performance effects in pigs fed sorghum. [ABSTRACT FROM AUTHOR]

Context: Australian sheep breeding values (ASBVs) for lambing ease (LE) are estimated by Sheep Genetics, by using a threshold animal model at the lamb level, in a tri-variate analysis that includes data on birth weight, gestation length and lambing ease score. The implications of these traits for lamb survival, or the use of other indirect traits to improve accuracy of ASBVs for LE, are not currently being considered. Ultimately, it is desirable to extend the analysis to outcomes for individual lamb survival. Aim: The present study investigated implications of LE for lamb survival outcomes, accounting for litter size, and examined associations with other traits recorded at or shortly after lambing in maternal sheep breeds. Methods: Equivalent linear models were used to compare lamb- and ewe-level models with various combinations of additional random effects. In particular, lambing ease was treated as a different trait for single-born and twin-born lambs, to identify changes in genetic correlations associated with litter size between LE and other traits. Other traits included lambs recorded dead at birth, survival to weaning, lamb birth weight, gestation length and maternal behaviour score. Key results: Individual lamb survival outcomes inferred from field data and dead at birth lambs, are lowly heritable traits influenced by both direct and maternal effects. Lamb survival is positively correlated with birth weight, but negatively correlated with gestation length, lambing ease score (increasing lambing difficulty) and dead at birth lambs. Genetic and phenotypic correlations demonstrated that birth weight and lambing ease are antagonistic traits, more so for single-born lambs. Genetic correlations were moderate between dead at birth lambs and LE (0.40–0.45 singles; 0.15–0.36 including data from twins) or lamb survival (−0.63 to −0.81 singles; −0.00 to −0.23 including data from twins) and can add to the accuracy of genetic evaluation for these traits. In contrast, maternal behaviour score was predominantly an ewe trait, and will therefore add to accuracy of evaluation only for maternal effects. Lamb-level models appeared to underestimate heritability, sometimes compensated for by larger variance, and over-estimate genetic correlations for some traits relative to ewe-level models. Conclusions: Expanding the current lambing ease analysis to include dead at birth records and lamb survival outcomes would provide more detailed options for breeders to develop breeding goals to improve outcomes for both ewes and lambs. Further work is required to expand analyses to include threshold and continuous traits and understand genetic contributions to ewe survival traits. Implications: Relative selection emphasis on LE and birth weight must be considered in light of the expected litter size in which lambs will be born, to ensure favourable outcomes for lamb survival overall. Accuracy of genetic evaluation for LE can be improved using data on dead at birth. Equivalent ewe model analyses are possible. Completeness of pedigree, availability of informative lamb level data and integration with other traits are also factors to consider for the choice between operational lamb- versus ewe-level models for genetic evaluation systems. The present study investigated implications of lambing ease for lamb survival outcomes, accounting for litter size, and examined associations with other traits recorded at or shortly after lambing in maternal sheep breeds. Individual lamb survival outcomes inferred from field data and dead at birth lambs are lowly heritable traits influenced by both direct and maternal effects. Expanding the current lambing ease analysis to include dead at birth records and lamb survival outcomes would provide more detailed options for breeders to develop breeding goals that will improve outcomes for both ewes and lambs. [ABSTRACT FROM AUTHOR]

Context: Fat colour is one of the most important economic traits in the marketing of beef. There are many factors that affect fat colour, such as breed, age, diet and gender. Fat colour is observed in different ranges of colours, including white, yellow and brown. The main issue with improving fat colour is that consumer preferences of fat colour vary across the globe. Therefore, investigating the metabolic mechanisms of fat colour may provide new biomarkers for phenotyping, so as to develop effective selection strategies to achieve the locally desired fat colour. Aims: This study aimed to perform a comparative metabolic analysis between white and yellow fat from crossbred cattle so as to identify potential biomarkers for the selection of fat colour and to better understand the metabolism of white and yellow fat depots. Methods: Carcass samples of subcutaneous fat were collected from crossbred cattle (Simmental × Mongolian cattle) and scored for fat colour. Liquid chromatography–mass spectrophotometry analysis of extracted metabolites from the subcutaneous fat of six animals with white fat and six animals with yellow fat was performed. Key results: The comparison between metabolites of white and yellow fat colour samples indicated that there were five categories of 235 significant metabolites, which included hydrocarbons, lipids and lipid-like molecules, organic acids and their derivatives, organic oxygen compounds and organoheterocyclic compounds. The principal-component analysis illustrated that yellow and white fat samples can be classified in groups; however, the metabolites of white fat samples showed greater variation than those in the yellow fat. In the white fat, there were 163 metabolites that had a higher relative abundance than in yellow fat and 72 that had a lower relative abundance than in yellow fat. 3-Hydroxyoctanoic acid, anethofuran, 9,10-DiHODE, furanoeremophilane, pregeijerene, N-glycolylneuraminic acid, and glycocholic acid were identified as the metabolites that differed the most in abundance between the white and yellow fat samples. Conclusions: This study has provided insights into the metabolic differences between white and yellow fat depots and identified key metabolites associated with beef fat colour. Implications: This study has provided potential biomarkers that may be useful for selection of beef fat colour in live animals. Fat colour is a major parameter for evaluating meat quality and is important in the beef industry. We performed analysis between white and yellow fat, so as to identify potential biomarkers for the selection of fat colour. These biomarkers are helpful with understanding of the molecular basis of fat colour. [ABSTRACT FROM AUTHOR]

Context: Genome-wide association studies (GWAS) and meta-analyses can be used to detect variants that affect quantitative traits. Multi-breed GWAS may lead to increased power and precision compared with within-breed GWAS. However, not all causal variants segregate in all breeds, and variants that segregate in multiple breeds may have different allele frequencies in different breeds. It is not known how differences in minor allele frequency (MAF) affect multi-breed GWAS and meta-analyses. Aims: Our aim was to study the impact of differences in MAF at causal variants on mapping power and precision. Methods: We used real imputed sequence data to simulate quantitative traits in three dairy cattle breeds. Causal variants (QTN) were simulated according to the following three scenarios: variants with a similar MAF in all breeds, variants with a lower MAF in one breed than the other, and variants that each only segregated in one of the breeds. We analysed the simulated quantitative traits with three methods to compare mapping power and precision: within-breed GWAS, multi-breed GWAS and meta-analysis. Key results: Our results indicated that the multi-breed analyses (multi-breed GWAS or meta-analysis) detected similar or more QTN than did within-breed GWAS, with improved mapping precision in most scenarios. However, when MAF differed between breeds, or variants were breed specific, the advantage of the multi-breed analyses over within breed GWAS decreased. Regardless of the type of QTN (similar MAF in all breeds, different MAF in different breeds, or only segregating in one breed), multi-breed GWAS and meta-analyses performed similar or better than did within-breed GWAS, demonstrating the benefits of multi-breed GWAS. We did not find large differences between the results obtained with the meta-analysis and multi-breed GWAS, confirming that a meta-analysis can be a suitable approximation of a multi-breed GWAS. Conclusions: Our results showed that multi-breed GWAS and meta-analysis generally detect more QTN with improved precision than does within-breed GWAS, and that even with differences in MAF, multi-breed analyses did not perform worse than within-breed GWAS. Implications: Our study confirmed the benefits of multi-breed GWAS and meta-analysis. Combining data from multiple cattle breeds may help identify variants that affect important quantitative traits. However, when these variants occur with different allele frequencies in different breeds, the advantage of multi-breed analyses over within breed analyses can reduce. Our results demonstrated the potential benefits and limitations of multi-breed analyses. [ABSTRACT FROM AUTHOR]

Context: Feed is the largest expense on a dairy farm, therefore improving feed efficiency is important. Recording dry-matter intake (DMI) is a prerequisite for calculating feed efficiency. Genetic variation of feed intake and feed efficiency varies across lactation stages and parities. DMI is an expensive and difficult-to-measure trait. This raises the question of which time periods during lactation would be most appropriate to measure DMI. Aims: The aim was to evaluate whether sequence variants selected from genome-wide association studies (GWAS) for DMI recorded at multiple lactation time periods and parities would increase the accuracy of genomic estimated breeding values (GEBVs) for DMI and residual feed intake (RFI). Methods: Data of 2274 overseas lactating cows were used for the GWAS to select sequence variants. GWAS was performed using the average of the DMI phenotypes in a 30-day window of six different time periods across the lactation. The most significant sequence variants were selected from the GWAS at each time period for either first or later parities. GEBVs for DMI and RFI in Australian lactating cows were estimated using BayesRC with 50 k single nucleotide polymorphisms (SNPs) and selected GWAS sequence variants. Key results: There were differences in DMI genomic correlations and heritabilities between first and later parities and within parity across lactation time periods. Compared with using 50 k single-nucleotide polymorphisms (SNPs) only, the accuracy of DMI GEBVs increased by up to 11% by using the 50 k SNPs plus the selected sequence variants. Compared with DMI, the increase in accuracy for RFI was lower (by 6%) likely because the sequence variants were selected from GWAS for DMI not RFI. The accuracies for DMI and RFI GEBVs were highest by using selected sequence variants from the DMI GWAS in the mid- to late-lactation periods in later parity. Conclusions: Our results showed that DMI phenotypes in late lactation time periods could capture more genetic variation and increase genomic prediction accuracy through the use of custom genotype panels in genomic selection. Implications: Collecting DMI at the optimal time period(s) of lactation may help develop more accurate and cost-effective breeding values for feed efficiency in dairy cattle. Genetic improvement of feed efficiency to produce milk in dairy cattle would provide considerable economic benefits but measuring feed intake is difficult and expensive. Therefore, we used existing data to determine the best period of lactation to measure feed intake and then used advanced genomics to improve the accuracy of genomic breeding values for feed intake and efficiency. The results are an important step towards a more accurate and cost-effective approach to genetically improve dairy cow feed efficiency. [ABSTRACT FROM AUTHOR]

Context: The Australian dairy industry has a target to reduce greenhouse-gas (GHG) emissions intensity by 30% between 2015 and 2030. At the animal level, apart from nutritional modifications and other management practices, selecting animals that emit less GHG can be a cost-effective and long-term strategy. Given the world's demand for protein is increasing, selecting for animals with lower GHG emissions per unit of production, i.e. emissions intensity, is a realistic approach that addresses the key issue of emissions reduction while maintaining farm productivity. Aim: To develop a selection index for Australian dairy cattle to breed for reduced emissions intensity. Methods: The Sustainability Index was built based on the existing Balanced Performance Index (BPI) but placed greater emphasis on production, survival, health and feed efficiency. Key results: In August 2022, DataGene released the Sustainability Index that can be used by dairy farmers to select animals with lower environmental footprints. Compared with BPI, the weights for protein, fat, survival, mastitis resistance and feed efficiency increased by 2.6-, 1.4-, 2.8-, 1.3- and 3.8-fold respectively. It is expected that with the use of the Sustainability Index, emissions intensity will be reduced by 7.64%, 8.96% and 5.52% respectively in Holstein, Jersey and Red breeds by 2050, compared with the 2015 level. The corresponding values when selecting for BPI were 6.34%, 7.91% and 5.23% respectively. However, the trade-off in BPI when using the Sustainability Index will be AUD0.79, AUD0.83, AUD0.22 per cow per year for Holstein, Jersey and Red breeds respectively. Conclusions: The current profit index BPI has contributed to reduction in emissions intensity. To enhance the rate of improvement in emissions intensity, the Sustainability Index can be used with minimal impacts on profit. Implications: To breed for lower emissions intensity, farmers can select animals with high Sustainability Index values that are published on DataVat (datavat.com.au) and the Good Bulls App. To lower gross emissions, combinations of additional measures such as management of diet, adjustment to animal numbers, management of stored manure, and appropriate use of carbon neutral fertiliser, renewable fuels and energy, will need to be adopted on farms. Improving environmental sustainability through reduced greenhouse-gas (GHG) emissions is a global priority. An index was developed that can be used to breed for lower emissions intensity in Australian dairy cattle, with minimal impacts on profit. This is an additional tool in the toolbox that can be used in combination with others to help farmers reduce overall emissions on farm. [ABSTRACT FROM AUTHOR]