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Context: Animal production plays a critical role in many global challenges around sustainability, including climate change and resilience, One Health and food security. With this role comes pressures on livestock welfare. Aims: This paper demonstrates key contributions animal welfare makes to global sustainability challenges. Methods: This paper highlights 'win–win' improvements for both animal welfare and other aspects of sustainability by using the following four case studies: tail docking Australian sheep, agroforestry systems in Ethiopia, the Australian dairy-beef industry, and strategic feeding of goats in Pakistan. Key results: These case studies show how animal welfare can be improved alongside livelihoods. However, even in these win–win situations, the adoption of improved practices is not guaranteed. Conclusions: Long-term, sustained change in animal welfare can simultaneously make in roads to other challenges around sustainability. To do this, we must have a broader understanding of the system in which the animals are raised, so that barriers to change can be identified. Implications: Lessons from these case studies can be applied to other production contexts and challenges, highlighting the universal value of understanding and addressing animal welfare. Global challenges around sustainability are putting different pressures on the welfare of livestock. This paper highlights 'win–win' improvements for both animal welfare and other aspects of sustainability, but even in these win–win situations, the adoption of improved practices is not a guarantee for a myriad of external factors. By having a better understanding of the system in which animals are raised, a broader understanding of an animal's welfare, and acknowledging the emotional states that animals experience, progress towards improving welfare and, ultimately, addressing some of these global challenges, can be made. [ABSTRACT FROM AUTHOR]

The rise of sequencing technology brought about a surge of new methodologies that offered a new and deeper level of understanding of the role of the microbiome in the health and performance of livestock. This started a chain reaction in technology evolution, and a decade later, we have developed a new appreciation of a healthy gut and the role of early colonisation and nutrition in developing the microbiome, and its subsequent impact on animal productivity. An abundance of new products flooded the livestock supplement market with the promise of improving the health of intestinal microbiota. However, the impact of these products and any potential gains they might provide have not always been quantified or validated. Further to this, the potential interactions with the microbial community naturally occurring in the feed-base have not commonly been considered. We have recently shown that animal feed carries a complex microbial community that can have various impacts, including negating farm biosecurity measures. The ruminant animal provides an even greater level of complexity where physiological drivers act to maintain ruminal homeostasis. Despite many advances, numerous knowledge gaps remain, and the methodologies are not without their challenges with almost constant evolution in analysing and interpreting data. In this paper, we will discuss the benefits, challenges and shortfalls of microbiome science, its interfaces with multi-omics research and the strategies of its contribution to animal production science. With advances in sequencing technology, research of microbial communities has become more accessible and affordable. In livestock research, the roles of microbiota are associated with animal performance and welfare. Although universally accepted, amplicon-sequencing methodology has several issues that need to be considered in data interpretation. Here we review the main shortfalls, benefits and uses of the methodology in livestock research. [ABSTRACT FROM AUTHOR]

Context: A significant opportunity remains to further increase the supply of premium sheepmeat products to Australia's customers, which requires a more rapid rebuilding of the national sheep flock. To help meet this challenge, developing relevant information for sheep producers to assist them to achieve a profitable flock-rebuilding outcome is viewed as highly desirable. Aims: (1) Develop flock-rebuild scenarios that track inventory, cashflow, profit and loss, and the overall balance sheet over a 5-year projection. (2) Model the impact on flock-rebuilding pathways of exposure to variation in supplementary-feed costs, purchase of stock and price received for sale animals and flock structure. (3) Model variation in benefits and costs for a range of production zones, enterprise types and flock-age profiles. Methods: Fourteen flock-rebuilding pathways were assessed for up to nine flock types, using a spreadsheet model that tracked inventory, cashflow, profit and loss, and the overall balance sheet over 5 years. Key results: The top four pathways for profitability and capacity to rapidly rebuild flock numbers include retention of more older ewes, purchasing young ewes, purchasing older ewes (mostly 5–6-year olds) in Merino and Merino-cross flock types only and joining ewe lambs in Maternal and Cleanskin flock types only. These pathways were not sensitive to variation in the cost of supplementary feed, stock prices or flock structure, although joining Merino ewe lambs became one of the top four pathways when feed costs were lower. Conclusions and implications: The well established practices of retaining ewes for longer and purchasing ewes, especially young ewes, have the most potential to both rapidly and profitably rebuild flock numbers. However, joining ewe lambs, particularly in Maternal and Cleanskin flocks, can also profitably contribute to rapid flock rebuilding. While reducing reproductive wastage or increasing reproductive potential were mostly profitable, they could not rapidly rebuild flock numbers. In contrast, accelerated lambing systems can rapidly rebuild flock numbers, but are only marginally profitable. The outlook for Australia's sheepmeat industry is very positive, with a significant opportunity available to further increase the supply of premium sheepmeat products to customers, by more rapidly rebuilding the national flock. This paper presents the findings of a study focussed on providing the confidence and material to sheep producers to choose optimal pathways to rebuild their flocks. At least 6 of the 14 alternatives investigated were deemed suitable for commercial use and not sensitive to variations in supplementary-feed costs, stock-purchasing and -sale prices. [ABSTRACT FROM AUTHOR]

Context. As a 'duty of care', it is important to test whether new forage plants for ruminants contain secondary compounds (PSCs) that affect reproductive performance. We have previously observed, a posteriori, that the presence of a methanolic extract of Biserrula pelecinus during maturation of sheep oocytes increased fertilisation rate and blastocyst development. This result needed to be verified a priori and, if the outcome was repeated, we needed to identify the plant secondary metabolite responsible. Aims. To test whether PSCs from B. pelecinus, when added to the oocyte maturation medium, improve fertilisation rate and blastocyst development; to test whether loliolide is the active molecule produced by B. pelecinus. Methods. Methanol-chloroform extracts of B. pelecinus were fractionated using rapid silica filtration and solvents of increasing polarity. Fractions at final concentrations of 0, 100 or 200 µg mL-1 were added to the medium used to mature sheep cumulus-oocyte complexes (COCs) and effects were determined for maturation, subsequent cleavage rate, blastocyst rate, hatching rate, blastocyst efficiency and total blastocyst cell number (TCN). Results. Fraction BP-6 at 100 µgmL-1 reduced blastocyst rate (P < 0.05), but had no effect when the dose was doubled to 200 µg mL-1. Further fractionation using semi-preparative high-performance liquid chromatography showed loliolide as the most abundant compound in BP-6. Supplementation of the in vitro maturation medium with loliolide (0, 2.5, 5, 10 and 25 µgmL-1) did not affect any measure of embryo development. All COCs treated with B. pelecinus fractions reached the final stage of embryo development, blastocyst hatching. Total blastocyst cell number was not affected. Conclusion. The presence of fractions of B. pelecinus extract during in vitro oocyte maturation can reduce embryo development. Implications. In vitro techniques can detect potential effects of forages on reproduction. Some fractions from an extract of B. pelecinus when present during oocyte maturation can reduce embryo development. The abundant PSC, loliolide, was not responsible. There was no indication that a PSC in B. pelecinus improves outcomes. [ABSTRACT FROM AUTHOR]

Context: The demand and production of renewable fuels are boosting the production of biofuels. Agricultural industries have been playing a role in the increase of ethanol production from corn and, consequently, their by-products. Dried distiller's grain (DDG) is a by-product of corn ethanol and can be used as a source of protein and energy in the diet of feedlot lambs. Aims: The objectives of this experiment were to evaluate the effects of including DDG in high-concentrate diets on performance, rumen morpho-histology, and carcass characteristics in feedlot lambs. Methods: Forty-five Santa Inês × Dorper male lambs with an initial body weight of 21 ± 3.2 kg (mean ± s.d.) and 82 ± 12 days old (mean ± s.d.) were distributed in a randomised complete-block design (nine blocks and five treatments). The experimental diets contained 900 g/kg of concentrate and 100 g/kg of coastcross hay, and DDG was used in replacement of soybean meal and corn. Lambs were fed one of the following five diets for 112 days: control without DDG (0DDG), or diet with 150 (150DDG), 300 (300DDG), 450 (450DDG) and 600 (600DDG) g/kg DM of DDG. Key results: The inclusion of DDG from 150 up to 600 g/kg DM in the diet of the lambs linearly decreased (P < 0.01) dry-matter intake (DMI), net energy of maintenance intake, net energy of gain, average daily gain, final body weight and feed efficiency (P < 0.01). The inclusion of DDG linearly decreased (P ≤ 0.04) hot carcass weight, cold carcass weight, hot carcass yield and cold carcass yield. For ruminal morpho-histology, there was a linear decrease in the area of papillae and absorptive surface area (P < 0.01) Conclusions: An increase in the DDG level from 150 to 600 g/kg DM in the diet of lambs negatively affected feedlot performance, with detrimental effects on carcass traits and the development of rumen papillae. The lambs showed low acceptance of DDG, even at the lowest level of dietary inclusion (150g/kg DM) as DMI was impaired. Implications: DDG should be used with caution in diets for finishing lambs. Dietary inclusion of DDG up to 150 g/kg DM is recommended. Higher inclusions levels may significantly affect performance and carcass weight and yield. There is great availability of dried distiller's grains (DDG) for ruminant feeding in Brazil, but little information on their utilisation. Lambs showed low acceptance of DDG, even at the lowest level of dietary inclusion (150 g/kg DM), as DMI was impaired. Feeding DDG decreased ADG and the carcass traits of feedlot lambs. This research showed the need for further studies on feeding lambs with other types of Brazilian DDG. [ABSTRACT FROM AUTHOR]

Context: There is some evidence that physiological stages such as breeding, pregnancy, parturition and lactation may trigger oxidative stress. It has also been observed in several species, including sheep, that age affects their vulnerability to oxidative stress. Aims: This study investigated the effects of supplemental β-carotene and age on the oxidative status of grazing ewes around breeding, pregnancy, parturition and early lactation as well as on their production and reproduction performance. Methods: Hundred and four ewes were divided into two broad age groups (young = 1–3 years, and old = 4–6 years). Within age groups, ewes of similar age were randomly assigned to four treatment groups (A1, A2, A3, C) by using a completely randomised block design. The young (n = 13) and old (n = 13) sheep in Groups A1, A2 and A3 were daily drenched with 100 mg, 75 mg and 50 mg β-carotene respectively. Group C was unsupplemented (Control). Supplementation lasted 28 days before oestrus synchronisation; 14 days during oestrus synchronisation (CIDR) and hand-mating; 18 days post-hand-mating; 30 days before lambing; and 15 days after lambing. All animals were grazed on Kikuyu grass (Pennisetum clandestinum). Six ewes from each group (total = 24) were sampled for blood to measure oxidative and hormonal status during the experiment. Key results: Supplemental β-carotene at ≥75 mg/day may act as a pro-oxidant in ruminants under oxidatively stressed conditions such as parturition. Age did not affect the ewes' oxidative status. The supplemental β-carotene did not affect bodyweight, oestrus parameters, corpus luteum size, conception rate and litter size. Except for a tendency of lambs from supplemented ewes to have heavier weight at 15 days old (P = 0.080), age group and supplemental β-carotene did not affect the lamb mortality rate or weight at birth or 15 days old. Older ewes showed earlier and longer duration of oestrus than did younger ewes. Conclusions: Supplementation of grazing ewes with β-carotene should not be ≥75 mg/day, especially at parturition period, because it may work as a pro-oxidant. The older ewes seem to have earlier oestrus with a longer duration than do the younger ones. Implications: Caution is urged when administering high doses of β-carotene to ewes during the peri-parturient period. Normal physiological stages such as breeding, pregnancy, parturition, and lactation can cause oxidative stress, which may impair female reproductive performance. We examined the effects of β-carotene supplementation and age on the oxidative status and reproduction performance of grazing ewes during these stages. The study concluded that supplemental β-carotene at ≥75 mg/day may act as a pro-oxidant during parturition. However, this effect does not appear to manifest in lower survival or additional stress for the ewe and lamb. [ABSTRACT FROM AUTHOR]

Context: Brazilian red propolis stands out for its diverse composition, which includes phenolic compounds whose effects may be similar to those of synthetic feed additives. Aims: The objective of this study was to evaluate the effects of red propolis extract on the carcass and meat characteristics of lambs finished under confinement conditions. Methods: The meat quality characteristics of the longissimus lumborum muscle were evaluated in 35 Santa Inês lambs, with an average age of 5 months and an initial average body weight of 17.08 ± 2.36 kg (mean ± s.d.), submitted to five distinct treatments (0, 7, 14, 21, 28 mL of red propolis extract/animal.day) over 68 days. Key results: The use of propolis did not affect (P > 0.05) the characteristics of the carcass, as well as the chemical composition and cholesterol content. Among the physico-chemical parameters of meat, only the shear force had a quadratic effect (P < 0.05). There was also an exponential effect for lipid oxidation (P < 0.05), where the treatment with propolis had greater antioxidant effect. Meat with a lower content (P < 0.05) of saturated fatty acids was observed in sheep that received extract. There was also an increase (P < 0.05) in the content of monounsaturated acids and consequently an improvement in nutritional quality, atherogenicity and thrombogenicity indexes of desirable fatty acids. Conclusions: The red propolis extract improved the lipid profile of the lamb meat. We recommend the inclusion of 7 mL red propolis extract/animal.day (or 59.50 mg total flavoloids/animal.day) in the diet of lambs finished under confinement conditions. Implications: The red propolis extract proved to be a viable alternative as a natural feed additive. Red propolis extract was offered at increasing levels to feedlot lambs and we observed that the animals' carcass weight and physico-chemical parameters of the meat were not influenced by these treatments. Furthermore, the inclusion of 7 mL/day of extract in lamb diet was enough to reduce the oxidation of lamb meat, and also improved the lipid profile. We recommend the inclusion of 7 mL/day of red propolis extract in the diet of feedlot lambs. [ABSTRACT FROM AUTHOR]

Context: Grazing of cereal forage crops is perceived as a risk for increased perinatal lamb mortality. Aims: This study evaluated whether grazing oat forage during late pregnancy and/or the lambing period increased lamb mortality compared with grazing a legume (lucerne)-based pasture. Methods: Merino ewes (n = 636) were allocated to two replicates of two litter sizes (singles or twins), which grazed the following three forage treatments: either legume-based pasture or oat forage (Avena sativa) from 42 days before and throughout a 4-week lambing period, or a legume-based pasture until 9–12 days pre-lambing before grazing oats throughout the lambing period. All groups were offered a calcium, magnesium and sodium mineral supplement to reduce the risk of deficiency. Key results: Lamb survival to marking was similar for ewes grazing legumes (84.2 ± 1.94%) or oat forage (78.5 ± 1.94%) throughout, but was reduced (P = 0.022) for ewes that grazed oats only during the lambing period (71.0 ± 1.94%) compared with those that remained on legumes. The latter was associated with a greater (P = 0.016) loss of condition score in the ewes. The weight of lambs at marking age was 2 kg higher (P ≤ 0.05) when grazed on legume-based pasture during the 4 week lambing period rather than oats. Minimal ewe mortality (0.47%) occurred, no metabolic disease was observed and few ewes (1.3%) required assistance at parturition. None of the sampled ewes was subclinically deficient in calcium or magnesium. Conclusions: The study indicates lamb survival was not reduced by grazing oats for an extended period throughout late pregnancy and lambing. Further research is required to determine whether the recorded reduction in lamb survival from grazing oats only during lambing occurs consistently. Implications: Ewes may safely graze oat forage throughout late pregnancy and lambing when offered a calcium, magnesium and salt supplement, without this increasing perinatal lamb mortality relative to a legume-based pasture, but there may be a penalty in lamb growth rates and loss of ewe condition, and lamb survival may be reduced with an abrupt change to oats for the lambing period. Grazing of cereal forage by late-pregnant and lambing ewes is perceived as a risk to perinatal lamb survival. This study investigated whether the duration of grazing ewes on oat forage would reduce lamb survival, and found that grazing oats continuously through late pregnancy and lambing gave similar survival as did grazing legume pasture, whereas grazing oats only during lambing reduced survival. Producers may safely graze oats with late pregnant ewes when supplemented with calcium, magnesium and salt. [ABSTRACT FROM AUTHOR]

Context: Timely pregnancy diagnosis is critical for reducing non-production days and improving the reproductive efficiency of sheep flocks. Aims: The aim of this study was to investigate the serum proteomic profile of ewes in different gestational stages and explore the potential of differentially expressed proteins as biomarkers for early gestation. Methods: Serum samples were collected from two groups: pregnant sheep (n = 4) and non-pregnant sheep (n = 4) on Day 14 after mating. The differentially expressed proteins were detected using tandem mass-tag (TMT) labelling with liquid chromatography tandem-mass spectrometry. The differentially expressed proteins were confirmed using enzyme-linked immunosorbent assay (ELISA). Furthermore, six selected proteins were evaluated in ewes (n = 35) on Day 14 from mating by using ELISA to assess their potential as biomarkers for early pregnancy. Receiver-operating characteristic (ROC) curves were used to analyse the diagnostic accuracy of these proteins. Key results: Twenty proteins, of a total of 555 proteins detected, showed differential expression between pregnant and non-pregnant sheep. From the ROC-curve data, CHI3L1 (AUC = 0.992), PSMB4 (AUC = 0.976) and LGALS3BP (AUC = 0.844) had high predictive value in the diagnosis of early pregnancy. Conclusions: In this study, CHI3L1, PSMB4 and LGALS3BP were found to be differentially expressed proteins in the serum of pregnant sheep. Therefore, these three proteins carry a high probability as candidate biomarkers for early gestational embryo attachment in ewes. Implications: Early pregnancy diagnosis enables timely identification of non-pregnant ewes, resulting in optimised resource allocation and enhanced economic benefits for farmers by reducing production costs. The present study enables to advance the diagnosis of pregnancy in ewes to the first oestrous period after breeding. The differentially expressed protein in serum was found to be a highly specific and sensitive biomarker for early pregnancy diagnosis in ewes. Its application in production can reduce the number of days of mating loss in ewes, reduce production costs and improve economic efficiency. [ABSTRACT FROM AUTHOR]

The proximity of rail corridors to livestock production enterprises poses potential risks to welfare and production. The association between these factors and production have been extensively investigated. This review aims to assess the potential impact on the basis of existing data in a livestock production context. Due to expansion of freight rail networks through agricultural land, there is a need to investigate potential impacts of rail (including train and track) noise, vibration and visual disturbance on the physiology and behaviour of the livestock and subsequent production traits. Additionally, the factors influencing the impact on animals were characterised broadly as noise, vibration, and visual and spatial disturbance. This information was used to develop conceptual frameworks around the contribution of rail impact on allostatic load, animal welfare and production. Placing rail noise in the context of other, known, noise impacts showed that proximity to the rail line will determine the impact of noise on the behaviour and physiology of the animal. Thresholds for noise levels should be determined on the basis of known noise thresholds, taking into account the impact of noise on allostatic load. Further research is recommended to investigate the behavioural, physiological and production impacts on livestock from proximity to rail corridors. Current literature suggests that the allostatic load will vary depending on the proximity of the animal to the source of stimulus, the type, size or level of stimuli, habituation and the individual animal variation in response to the stimuli. [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. 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: Coping with high levels of cold stress should be beneficial to survival of lambs, given the high mortality rate associated with severe winter storms. The Elsenburg Merino selection experiment involved divergent selection for reproduction. Phenotypic results comparing the positively selected H-Lines and negatively selected L-Lines suggested that cold-stress adaption could have contributed to the favourable genetic trends for survival of H-Line lambs. However, observing the genetic merit of better adapted animals depends on the presence of cold stress at the time of recording. A genotype by environment component (G × E) could, thus, be important when assessing survival/mortality phenotypes. Aim: This study proposed the genetic analysis of this possible G × E component and compared the H- and L-Lines in this regard. Methods: The sire model allowed the use of progeny phenotypes for neonatal mortality recorded during different levels of cold stress, and the possible G × E could be investigated through the reaction-norm approach. Genetic parameters were evaluated as random regression components by implementing a Gibbs sampling approach. A data set of 5723 individual lamb records was analysed as the progeny of 213 sires. Results: A modelled G × E component played an important role in mortality outcomes, with the mean estimate (and 95% confidence interval) for the slope ( σ s b 2 = 0.113 [ 0.0019 – 0.28 ] AN22464_IE1.gif) only marginally smaller than the corresponding estimate for the intercept ( σ s a 2 = 0.124 [ 0.003 – 0.26 ] AN22464_IE2.gif). The reaction-norm model showed a higher heritability (h 2 ± posterior standard deviation) for mortality at 3 days of age during high cold-stress (0.22 ± 0.16 at ~1100 KJm−2h−1) than during mild (0.13 ± 0.10 at ~960 KJm−2h−1) conditions, suggesting a greater ability to discriminate between sires at increasing stress levels. Conclusions: Failure to account for this G × E component putatively contributes to the low h 2 commonly reported for survival traits. The higher h 2 at increased levels of cold stress could have played an important part in the higher survival of the H-Line progeny, who were better at coping with cold, wet and windy conditions. Implications: Larger studies representing a wider environmental trajectory are recommended. This should be very feasible since cold stress can be derived from commonly available weather-station data. Animals better adapted to cope with cold stress conditions should have higher survival rates, but the merit of these animals would not be visible under mild conditions. Accounting for the level of cold stress in the earliest days after birth allows for new ways to evaluate the genetic merit of survival or mortality traits. Cold-stress adaption is likely to have been an important part of the very favourable survival rate of the Elsenburg Merino H-Line. [ABSTRACT FROM AUTHOR]

Context: Commercial beef and sheep producers have adopted using condition score for management of cows and ewes to maximise productivity. Significant premiums are being paid for bulls and rams with higher-fat breeding values based on young animal measurements, with the aim of increased resilience in adult female progeny. Aims: The aim of this study was to quantify the relationship between adult body condition score and young muscle and fat and also the genetic variation in condition that is independent of yearling traits. Methods: Published genetic parameters for four large data sets from Angus and tropically adapted cattle, and composite and Merino sheep were used to partition genetic variation in adult condition that is associated with, or independent of, young composition measures. Key results: One genetic standard deviation in young muscle or fat was associated with approximately just 0.1 adult body condition scores. Approximately ¾ of the genetic variation in adult body condition score (BCS) is independent of genetic variation in young weight and composition traits. Conclusions and implications: Producers need to be careful with premiums paid for bulls and rams with superior yearling composition traits with the aim of changing adult BCS. The best way to achieve this is for seedstock breeders to record and report breeding values for cow and ewe BCS. Commercial beef and sheep producers have adopted using condition score for management of cows and ewes to maximise productivity. Approximately ¾ of the genetic variation in adult body condition score (BCS) is independent of genetic variation in young weight and composition traits. Producers need to be careful with premiums paid for bulls and rams with superior yearling composition traits with the aim of changing adult BCS. The best way to achieve this is for seedstock breeders to record and report breeding values for cow and ewe BCS. [ABSTRACT FROM AUTHOR]

The affective states of animals comprise a key aspect of welfare that can be difficult to assess. An attention-bias test was developed for sheep, which assessed allocation of attention between a predator threat and a food reward, as a potential measure of affective state. The method was pharmacologically validated as a measure of anxiety-like states, finding that 'anxious' sheep were more vigilant, less likely to feed and spent more time looking towards the previous location of a dog than did 'calm' sheep. Across six further validation studies, the method was modified and explored as a measure of other types of affective states. This perspective article aims to provide guidance on what the method can tell us about affective state and make recommendations for further research by using this approach. Evidence was strongest across the studies for the test as a measure of anxiety-like states, but it is clear that there are other factors affecting animal behaviour during testing that need to be further investigated. One study showed potential for a modified method to assess depression-like states in sheep, while the impact of chronic stress on affect and attention bias remains unclear. It is likely that the test cannot be used to measure positive affect in sheep without further modification, due to the fear-eliciting nature of the test. Versions of the method using food as a positive stimulus allow for a clearer interpretation of attention than do versions using a conspecific photograph, and are recommended for use in future studies where appetite is not expected to be a confounding factor. In this context, vigilance behaviour may indicate trait anxiety or fearfulness, while other measures of attention may be more sensitive to transient changes in affect. Modifications to the method are suggested to allow for a clearer characterisation of attention in livestock species and to improve the practical application of the test. Overall, the attention-bias test shows promise as a measure of negative affective states, but the method is still very new and further research is needed to better determine its potential use as a welfare-assessment tool. Tools that consider the emotional states of livestock are needed for comprehensive welfare assessment. We examined a relatively new method called the attention-bias test, finding that it may provide a practical measure of negative emotional states and trait fearfulness in sheep and other livestock species. The attention-bias test can potentially be used in further research to better understand how management practices and environments affect livestock welfare, with an ultimate aim to improve welfare outcomes on-farm. [ABSTRACT FROM AUTHOR]

Context: Cattle and sheep emit methane, a potent greenhouse gas, as part of the fermentation process of feed digestion in their gut; however, the mechanisms explaining differences among animals in enteric methane production are not fully understood. Aim: To investigate whether variation among animals in their ability to digest their test ration was associated with phenotypic and genetic variation in methane production. Methods: The experiment used 135 Angus beef cattle measured for their phenotypic and genetic merit for methane production. The extent of digestion of the dry matter (DMD) in the test ration by individual cattle was determined using silica as a naturally present indigestible marker. Its concentration in feed consumed and faeces was determined using rapid portable X-ray fluorescence spectroscopy, from which DMD was calculated. Key results: Higher daily methane-production rate (MPR), higher methane produced per unit of feed consumed (methane yield; MY) and higher methane produced than the predicted daily production (residual MPR; RMP) by animals was accompanied by higher DMD. Higher genetic merit for MPR was also accompanied by higher DMD, but DMD had no detectable association with genetic variation in the other two methane emission traits. The regression coefficients for change in MPR (g/day), MY (g/kg DMI), RMP (g/day) with change in DMD (%) were 2.6 ± 1.1 (s.e.; P < 0.05), 0.14 ± 0.07 (P < 0.1) and 0.68 ± 0.38 (P < 0.1) respectively. Conclusions: Differences among animals in their DMD were found and were associated with phenotypic variation in the three methane emission traits studied, and with genetic variation in daily methane production. The results support the caution that feeding and breeding interventions seeking to reduce methane emissions can also reduce the extent of digestion of feed by cattle. Implications: Feeding and breeding interventions that seek to reduce methane emissions may change rumen physiology and reduce the extent of digestion of feed by cattle, which may be undesirable. Cattle and sheep emit methane, a potent greenhouse gas, as part of the fermentation process of feed digestion. Differences among animals in their ability to digest feed were found and were associated with variation in the three methane emission traits studied. Feeding and breeding interventions to reduce methane emissions may change rumen physiology and reduce the extent of digestion of feed by cattle, which may be undesirable. [ABSTRACT FROM AUTHOR]

Context: Monitoring the behaviour of animals can provide early warning signs of disease or indicate loss of appetite. Also, an understanding of the variation in behaviours among animals and their distributions is essential for meaningful statistical inference. Therefore, quantifying the variation of behaviours is of both biological and statistical interest. Aim: The objectives of this study were to determine the distributions and quantify the variation among animals with respect to the times spent grazing, ruminating, idling, walking, and licking. Methods: The activities of 147 (male = 67, female = 80) Merino lambs at 10–11 months of age on a commercial farm in Edenhope, Victoria, Australia were recorded for 26 days, using ActiGraph accelerometer sensors attached to the left side of the sheep's muzzle. The male and female sheep were kept in separate paddocks. A Support Vector Machine algorithm was used to differentiate sheep behaviour into six categories: grazing, ruminating, idling, walking, licking, and other activities. The distributions of behaviours were analysed using energy statistics-based tests and Generalised Additive Models for Location, Scale, and Shape (GAMLSS). Different distributions were compared using Akaike Information Criterion (AIC) values. Key results: Among the distributions that were considered, we found that times spent ruminating in both male and female sheep populations as well as idling in male sheep were best described by the skew exponential type 2 distribution. Grazing, walking and licking behaviours were best described by the Box–Cox t distribution. The distribution of time spent grazing was symmetrical and unimodal in males, and adequately modelled by a normal distribution, but the distribution in females had a prominent left skew. Also, we found that females typically grazed for a longer time than males. However, males spent more time ruminating than grazing. Conclusions: The time spent by the animal in each activity varied during the day. Within each population, the variation among animals in the time spent grazing was best described by a Box–Cox t distribution. Implications: This study has enhanced our understanding of grazing behaviour and will facilitate more appropriate analyses of the causes of variation among animals in grazing behaviour. This research quantifies the variation among sheep, with respect to the times spent grazing, ruminating, idling, walking and licking using an accelerometer. Variation in activity among sheep is of biological and statistical interest. This result enhances our understanding of sheep behaviours and allows for appropriate and meaningful statistical analyses in future experiments. [ABSTRACT FROM AUTHOR]

Context: The semiarid rangelands of northern Australia have high climate variability and a history of suffering periodic severe droughts. To remain viable, livestock businesses in the rangelands need to build resilience to climatic and market variability by regularly producing a profit and increasing wealth. Aims: Our aim was to use the farm-management economics framework to conduct a contemporary assessment of the profitability and resilience of alternative livestock enterprises in the semiarid rangelands of northern Australia. Methods: Livestock options were examined for a constructed, hypothetical property representative of the central-western Queensland rangelands (16 200 ha; long-term carrying capacity 1071 adult equivalents). First, the profitability of beef cattle, wool sheep, meat sheep and meat goat enterprises was assessed in a steady-state analysis using herd or flock budgeting models. Second, farm-level, partial discounted cash-flow budgets were applied to consider the value of integrating or fully adopting over time several of the alternative enterprises from the starting base enterprise of either a self-replacing (1) beef cattle herd or (2) wool sheep flock. Key results: In the steady-state analysis of existing enterprises, meat sheep and rangeland meat goat enterprises produced the greatest rate of return on total capital (3.9 and 3.7% per annum respectively). The operating profit, of all self-replacing herds or flocks, was most sensitive to meat prices. Where full investment in a wild dog exclusion fence around the boundary of the property, and some refurbishment of existing infrastructure, was required to convert from beef to small ruminant production, the investment increased the riskiness and indebtedness of the overall enterprise. This was the case even when the long-term operating profit of the property could be substantially improved, e.g. by a change to rangeland meat goats (extra A$45 700 profit/annum). Conclusions: Existing small ruminant enterprises in the semiarid rangelands of Queensland are profitable and resilient alternatives, based on contemporary prices. However, when changing from the predominant beef cattle enterprise, and incurring significant capital costs to do so, financial risk is substantially increased, which has implications for property managers. Implications: The farm-management economics framework should be used by individual grazing businesses for their specific circumstances, to support decision-making. To remain viable, livestock businesses need to build resilience to climatic and market variability by regularly producing a profit. The farm-management economics framework was used to conduct a contemporary assessment of livestock enterprises in the semiarid rangelands of Queensland. Existing small ruminant enterprises were profitable and resilient alternatives, based on contemporary prices. However, when changing from the predominant beef cattle enterprise, and incurring significant capital costs to do so, financial risk was substantially increased, which has implications for property managers. [ABSTRACT FROM AUTHOR]

Context. Genotype by environment interaction or sire re-ranking between measurements of methane emission in different environments or from using different measurement protocols can affect the efficiency of selection strategies to abate methane emission. Aim. This study tested the hypothesis that measurements of methane emission from grazing sheep under field conditions, where the feed intake is unknown, are genetically correlated to measurements in a controlled environment where feed intake is known. Methods. Data on emission of methane and carbon dioxide and uptake of oxygen were measured using portable accumulation chambers from 499 animals in a controlled environment in New South Wales and 1382 animals in a grazing environment in Western Australia were analysed. Genetic linkage between both environments was provided by 140 sires with progeny in both environments. Multi-variate animal models were used to estimate genetic parameters for the three gas traits corrected for liveweight. Genetic groups were fitted in the models to account for breed differences. Genetic correlations between the field and controlled environments for the three traits were estimated using bivariate models. Key results. Animals in the controlled environment had higher methane emission compared to the animals in the field environment (37.0 ± s.d 9.3 and 35.3 ± s.d 9.4 for two protocols vs 12.9 ± s.d 5.1 and 14.6 ± s.d 4.8 mL/min for lambs and ewes (±s.d); P < 0.05) but carbon dioxide emission and oxygen uptake did not significantly differ. The heritability estimates for methane emission, carbon dioxide emission and oxygen uptake were 0.15, 0.06 and 0.11 for the controlled environment and 0.17, 0.27 and 0.35 for the field environment. The repeatability for the traits in the controlled environment ranged from 0.51 to 0.59 and from 0.24 to 0.38 in the field environment. Genetic correlations were high (0.85-0.99) but with high standard errors. Conclusion. Methane emission phenotypes measured using portable accumulation chambers in grazing sheep can be used in genetic evaluation to estimate breeding values for genetic improvement of emission related traits. The combined measurement protocol-environment did not lead to re-ranking of sires. Implication. These results suggest that both phenotypes could be used in selection for reduced methane emission in grazing sheep. However, this needs to be consolidated using a larger number of animals and sires with larger progeny groups in different environments. [ABSTRACT FROM AUTHOR]

Cassava wastewater is a potential environmental pollutant, which can become a serious issue when improperly disposed into water bodies due to the toxic effects of cyanogenic glycoside. However, the presence of organic nutrients (starch and soluble sugars, mainly) supports the possibility of using this by-product in animal feeding. This study was conducted to examine the intake, apparent digestibility, performance, and carcass characteristics of feedlot lambs fed diets with increasing concentrations of cassava wastewater. The experiment involved 35 uncastrated Santa Inês crossbred lambs at approximately 3 months old, with an average bodyweight of 20 kg (standard deviation ± 3.4 kg). Diets were formulated with hay of cassava shoots (roughage), a maize- and soybean-based concentrate (50:50 roughage-to-concentrate ratio), and cassava wastewater at 0, 12, 24, 36 or 48 g kg−1 of the total diet (as-fed basis). Dietary inclusion of cassava wastewater led to a linear decrease (P < 0.05) in the intakes of dry matter, organic matter, crude protein, neutral detergent fibre, non-fibrous carbohydrates, and total digestible nutrients. Ether extract intake was not significantly (P > 0.05) influenced by cassava wastewater inclusion in the diets. There was no influence of cassava wastewater on the apparent digestibility of the nutritional components or on any parameter related to animal performance or carcass characteristics. Depending on the quantity, the use of cassava wastewater does not affect the feedlot performance of lambs. Cassava wastewater can be included in feedlot finishing diets at a level of up to 48 g kg−1 (as-fed basis). In ruminant supplementation, the main energy source used is maize; however, this product is a commodity that is influenced by the international market, and this often makes its use in animal feed unfeasible. To solve this problem, the use of agribusiness residues has been proposed in terms of animal nutrition, without causing significant changes in the nutritional value of diets. Depending on the quantity, cassava wastewater can be safely used in the ration of feedlot lambs. [ABSTRACT FROM AUTHOR]