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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]

In southern Australian grazing systems, energy availability typically exceeds energy requirements. Grazing systems are likely to have higher profitability if ewes can utilise this relatively cheap feed by gaining more condition (muscle and fat) and then mobilising it when feed is expensive. The present paper focusses on the importance of genetic merit for fat on the lifetime productivity of the ewe within a commercial operation. The analysis was carried out on a maternal composite stud flock in Holbrook,New South Wales. Ultrasound fat and muscle depth were measured on 2796 ewes as lambs at post-weaning and as adult ewes, to determine the genetic relationship between young and adult body composition. The hypothesis of the paper is that selection for increased fat at young age will improve body condition of adult ewes, which will lead to improved reproduction and potentially reduced requirements for supplementary feeding. Given that the difference in feed cost between times of abundance and shortage is likely to be larger, the system may become more profitable despite being less efficient (owing to increased feed intake). Our results indicated that selection for scanned post-weaning fat and muscle depth in lambs should lead to increased fat muscle and body condition in the breeding ewe because of strong genetic correlation estimates between the post-weaning and adult traits of 0.68-0.99. The influence of body composition traits on reproduction (number of lambs weaned) within the stud flock was weak. However, it is hypothesised that by genetically increasing post-weaning fat depth in ewes, producers could improve profitability by reducing the demands for supplementary feeding. [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]

In Somalia, located in the horn of Africa and one of the world's poorest countries, livestock are the mainstay of the economy. While strengthening the livestock sector is considered key to reduced poverty and increased food security, few studies have reported the livestock management practices of Somali pastoralists, including on breeding issues. Here, we present the final of a series of papers documenting the breeding practices of women and men Somali pastoralists for goat, sheep, camel and cattle. Data for the study were obtained by surveying 200 livestock-keeping households located within the Tog-Dheer region of Somaliland. The most important livestock species kept, in terms of contribution to household livelihood, were goats and sheep, followed by camel, then cattle. Migration with livestock was practiced by two-thirds of the households for some or all of the year, whereas other households were settled with their livestock. On breeding practices, the main means of acquiring breeding animals was by the animal being born into the herd, and varied means were used to control mating, including castration, culling, separation of male and female animals, purposeful mating of best males to best females, and controlling the size of mating groups. On beliefs on breeding issues, the pastoralists had a varied understanding of whether specific livestock traits were influenced by genetics, environment, or a combination of both, and most could not articulate the basis of inheritance. Knowledge of inbreeding was poor, with almost all respondents indicating they did not consider the mating of related animals to be problematic. Additionally, some pastoralists tried to influence the sex of the livestock progeny born through various practices. Overall, the finding presented here and in the companion studies (Marshall et al. 2014, 2016) indicated that the women and men Somali pastoralists generally employ sound breeding practices, although there is room for capacity building such as on inbreeding. Livestock are the mainstay of the economy in Somalia, one of the world's poorest countries. Here we document the breeding practices of women and men Somali pastoralists, for the main livestock species kept (goat, sheep, camel and cattle). Overall the pastoralists were found to employ sound breeding practices, although there is room for capacity building such as on inbreeding. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSN) offer a novel method for measuring important livestock phenotypes in commercial grazing environments. This information can then be used to inform genetic parameter estimation and improve precision livestock management. Arguably, these technologies are well suited for such tasks due to their small, non-intrusive form, which does not constrain the animals from expressing the genetic drivers for traits of interest. There are many technical challenges to be met in developing WSN technologies that can function on animals in commercial grazing environments. This paper discusses the challenges of the software development required for the collection of data from multiple types of sensors, the management and analyses of the very large volumes of data, determination of which sensing modalities are sufficient and/or necessary, and the management of the constrained power source. Assuming such challenges can be met however, validation of the sensor accuracy against benchmark data for specific traits must be performed before such a sensor can be confidently adopted. To achieve this, a pasture intake research platform is being established to provide detailed estimates of pasture intake by individual animals through chemical markers and biomass disappearance, augmented with highly annotated video recordings of animal behaviours. This provides a benchmark against which any novel sensor can be validated, with a high degree of flexibility to allow experiments to be designed and conducted under continually differing environmental conditions. This paper also discusses issues underlying the need for new and novel phenotyping methods and in the establishment of the WSN and pasture intake research platforms to enable prediction of feed intake and feed efficiency of individual grazing animals. Wireless sensor networks (WSN) offer novel methods for measuring livestock phenotypes in commercial grazing environments. We have established a program of research to measure intake, efficiency and behaviour of grazing livestock using WSN. This paper details the concepts, methods and technical challenges associated with establishing these WSN based methods, and some initial results from our program of research. [ABSTRACT FROM AUTHOR]

A reduction in voluntary food intake is a common feature of infection with pathogens and is frequently referred to as pathogen-induced anorexia. Anorexia has been previously viewed either as an unavoidable consequence of infection or as an animal strategy that enables them to cope with the consequences of infection. Both approaches lead to certain expectations as far as the characteristics of anorexia are concerned. By linking anorexia to host immune response one should be able to make predictions about when and for how long anorexia would occur. By appreciating what an infected animal is trying to achieve through its feeding behaviour, one would be able to make predictions about the extent of anorexia on different quality foods. The thesis of the paper is that these approaches should no longer be viewed as mutually exclusive, but, by combining them, one should be able to make pathogen-induced anorexia more predictable. This is done in the development of a model that aims to predict the food intake of grazing sheep exposed to an abomasal parasite. The predictions of the model are consistent with the features and consequences of parasite-induced anorexia of sheep given access to moderate and high quality foods. However, there is a degree of uncertainty about the validity of predictions made by the model on anorexia seen on poor quality foods of low energy content. This is not a deficiency of the model developed but can be attributed to the lack of appropriate experiments against which model predictions can be tested. The paper deals with the reduction in voluntary food intake (anorexia) that accompanies infection with pathogens. Its thesis is that the phenomenon would become more predictable if a causal and a functional approach to anorexia are combined. This is tested in the development of a simulation model that predicts the consequences of a gastrointestinal parasite in grazing sheep. [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]

Grazing management systems seek to control the relationship among animals, plants and soil by regulating the number of animals and the duration and location of animals. A greater understanding of the diet selection and activity of livestock within grazing systems will assist producers to make informed management decisions about their management within complex pastures. In the present paper, differences in the diet quality, selection and activity of ewes managed within contrasting systems (continuous-grazing (CG) and an intensive (20-paddock) rotational-grazing (RG) system) within a native pasture in the Central Tablelands of New South Wales, using non-invasive methodologies, are described. During two time periods (late spring and early autumn), the animals grazing within the CG system consumed a diet of higher quality and spent less time active than did those within the RG system. These differences resulted in higher individual animal production of CG animals that were able to maintain the herbage of preferred areas in a vegetative and highly nutritious state. The grazing animals selected the green herbage of higher quality than the average pasture and adjusted their selection seasonally. An underlying mechanism driving selection is the green : dead ratio of the herbage. Practically the results indicated that the green : dead ratio (or greenness) of herbage may provide a management trigger to enhance the production of animals grazing within a RG system, in particular during periods of higher requirement. [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]

This paper reports on genetic variation in the growth, wool production, carcass, reproduction and the bodyweight and body condition of ewes managed in the Information Nucleus Flock (INF), with a focus on evaluating the potential value of including adult ewe bodyweight and condition change traits in the Australian national sheep genetic evaluations provided by Sheep Genetics. Data were collected over a 7-year period (2007-2013) at eight research sites across southern Australia. Approximately 13 700 ewes were weighed and condition scored with ewes on average mated four times during the study. Adult ewe weight and body condition were recorded across the production cycle and the impact of the physiological status and change in status of the ewe on the genetic relationships with lamb growth, carcass and wool production traits was evaluated. Strong genetic correlations between measurements across the production cycle for adult ewe bodyweight and condition, low heritability of change traits, along with weak genetic relationships between change traits and key production traits suggest that in production systems where nutritional challenges can be managed, change traits provide no improvement to the current practice of using static bodyweight and condition records. The genetic variation in weight and body condition and their genetic relationships with production traits were highly consistent across ages and the production cycle. As a result, the current practice by Sheep Genetics to treat adult weight as a single trait with repeat records is most likely sufficient. However, the inclusion of body condition within the Sheep Genetics evaluation has potential to assist in improving maternal performance, and the feed costs associated with maintaining ewe body condition. [ABSTRACT FROM AUTHOR]

Our capacity to measure performance- and efficiency-related phenotypes in grazing livestock in a timely manner, ideally in real-time without human interference, has been severely limited. Future demands and constraints on grazing livestock production will require a step change beyond our current approaches to obtaining phenotypic data. Animal phenomics is a relatively new term that describes the next generation of animal trait measurement, including methodologies and equipment used to acquire data on traits, and computational approaches required to turn data into phenotypic information. Phenomics offers a range of emerging opportunities to define new traits specific to grazing livestock, including intake and efficiency at pasture, and to measure many traits simultaneously or at a level of detail previously unachievable in the grazing environment. Application of this approach to phenotyping can improve the precision with which nutritional and other management strategies are applied, enable development of predictive biological traits, and accelerate the rate at which genetic gain is achieved for existing and new traits. In the present paper, we briefly outline the potential for livestock phenomics and describe (1) on-animal sensory-based approaches to develop traits diagnostic of productivity and efficiency, as well as resilience, health and welfare and (2) on-farm methods for data collection that drive management solutions to reduce input costs and accelerate genetic gain. The technological and analytical challenges associated with these objectives are also briefly considered, along with a brief overview of a promising field of work in which phenomics will affect animal agriculture, namely efficiency at pasture. [ABSTRACT FROM AUTHOR]

The present study assessed the effectiveness and cost–benefit of several genotyping strategies for breeding poll Merino sheep in a closed nucleus with different initial allele frequencies and assuming a single-gene responsible for the horn or poll phenotype. We assumed that selection was based on phenotypes or genotypes for a single gene conferring polledness via a complete-dominance model. Under such a model, a complete fixation of the 'polled allele' (P) requires genotyping of the ewe-selection candidates. Testing a higher proportion of female candidates resulted in a faster fixation of the P-allele. Fixation ranged from 1 year of selection with a high starting P-allele frequency of 0.9, to 7 years for low starting P-allele frequencies of 0.3. When premiums of AU$50 or AU$100 were paid for rams with a PP genotype, breeding for PP genotypes was not profitable when the starting P-allele frequency was below 0.7. If the starting allele frequency was above 0.7, net profitability was positive over 10 years when premiums of AU$200 were paid for known PP-genotype rams. While fixing the P-allele, genetic gain for production traits was slowed down in the first 5 years of selection by up to 23% and 3% for initial P allele-frequencies of 0.3 and 0.9 respectively. Lost genetic gain due to fixing the P-allele, which can never be recovered in a closed nucleus, incurred 200–800% higher costs than the DNA testing costs. Rates of genetic gain recovered to pre-P-allele selection level rates of genetic gain once the P-allele was fixed. Testing a maximum of 25% ewe-selection candidates was the least expensive strategy across all starting allele frequencies and premiums. To avoid large losses of genetic gain in a closed nucleus with low P-allele starting frequencies, opening the nucleus should be considered to increase starting P-allele frequencies and also to potentially increase rates of genetic gain to offset the economic loss caused by P-selection. Australian Merino sheep can be bred with horns or without (polled). There is evidence suggesting polled rams are becoming more desirable due to increased welfare standards for both the individual sheep and their human handlers. As such there is indication that ram buyers will pay a premium for polled rams at present. This paper investigates breeding strategies to infuse the poll gene into a flock and the cost–benefit to the ram breeder. [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]

The profitability of a sheep enterprise is greatly influenced by the ability of the ewe to produce a lamb annually. This paper examines the between- and within-breed association between the liveweight and fat score of the adult ewe and key fleece, reproduction and milk production traits. The study analysed the performance of 2846 first-cross Merino and Corriedale ewes from the maternal central progeny test (MCPT) over their first three production cycles. Breed (9 sire breeds) and within-breed (91 sires) correlations were calculated from bivariate correlations of adult liveweight and fat score with fleece, reproduction and milk production traits. The mean liveweight and fatness of the breeds were low to moderately negatively correlated with greasy fleece weight (-0.55 and -0.25, respectively) and moderate to strongly positively correlated with fibre diameter (0.88 and 0.41, respectively). However, the within-breed correlations were generally low to negligible. The genetic relationships between ewe fat score and reproductive traits at the breed and within-breed level was generally low to negligible and, in some cases, negative under production conditions where the ewes were well managed and averaged a fat score of 3.5 pre-joining and became too fat across the production cycle. Strong breed correlations between ewe fat score and milk fat concentration (0.88) suggest that selection of fatter sire breeds will lead to increased fat in their progenies' milk, which was associated with larger lambs. The potential advantages of selecting for more fat to improve the maternal performance of the ewe seem to be limited in enterprises where the production system can easily be adjusted to restrict the influence of temporary and long-term feed deficiencies, as was achieved within the MCPT research flocks. [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]

Improving the reproductive performance of sheep is a national research priority, but identifying which components of the reproductive process should be the highest priority for further research is complex. The analysis reported in this paper tested the hypothesis that research areas can be prioritised using knowledge of potential gains and bio-economic modelling of critical control points. The analysis was carried out in two parts and the control points included increasing conception, increasing survival of single- or twin-born lambs, increasing survival of ewes at lambing, increasing weaner survival and increasing early reproductive success. For each control point, four productivity levels were examined and the average change in profit per unit of change in the control point per animal was calculated for three flock types. The second component quantified the potential industry gain from the change in profit per unit in each control point, the potential for change (number of units) and the potential adoption (number of ewes or weaners). On the basis of the assumptions used, increasing survival of twin-born lambs was the area with the highest pay-off and had an estimated value of AU$515 million. The value of increasing twin-lamb survival compared with single-lamb survival was affected by the proportion of single- and twin-bearing ewes in the flock. In a flock based on maternal ewes, there are relatively more twin-bearing ewes, so increasing twin survival was a higher priority than for flocks based on Merino ewes in which the proportion of twins was lower. The analysis suggested that the second most important area for future research was improving reproduction from ewe lambs with a pay-off of AU$332 million, followed by improving survival of ewes AU$303 million, improving survival of single born lambs AU$285 million, improving the number of lambs conceived AU$235 million, improving reproduction from 2-year-old ewes AU$221 million and, finally, improving weaner survival AU$52 million. The priorities determined using this method were robust and varying the assumptions of the bio-economic analysis had little impact on the priorities. There was no change in the overall ranking of the critical control points from either increasing the meat or wool price by 20% or altering the flock structure of the Merino flock. Therefore, we can be confident that the priorities determined in the present analysis with current prices and production systems will be valid in to the future. Improving the reproductive performance of sheep is a national research priority, but identifying which components of the reproductive process should be the highest priority for further research is complex. This analysis determined the potential benefit to industry from increasing conception, survival of single- or twin-born lambs, survival of ewes at lambing, weaner survival and early reproductive success. Increasing the survival of twin-born lambs was the area with the highest pay-off, whereas increasing weaner survival had the lowest pay-off. [ABSTRACT FROM AUTHOR]

The present paper covers reproductive performance in an artificial-insemination (AI) program of the Sheep CRC Information Nucleus with 24 699 lambs born at eight locations in southern Australia across five lambings between 2007 and 2011. Results from AI with frozen semen compared well with industry standards for natural mating. Conception rates averaged 72%, and 1.45 lambs were born per ewe pregnant for Merino ewes and 1.67 for crossbreds. Lamb deaths averaged 21% for Merino ewes and 15% for crossbreds and 19%, 22% and 20% for lambs from ewes that were mated to terminal, Merino and maternal sire types, respectively. Net reproductive rates were 82% for Merino ewes and 102% for crossbreds. From 3198 necropsies across 4 years, dystocia and starvation-mismothering accounted for 72% of lamb deaths within 5 days of lambing. Major risk factors for lamb mortality were birth type (single, twin or higher order), birthweight and dam breed. Losses were higher for twin and triplet lambs than for singles and there was greater mortality at relatively lighter and heavier birthweights. We conclude that reproductive rate in this AI program compared favourably with natural mating. Lamb birthweight for optimum survival was in the 4-8-kg range. Crossbred ewes had greater reproductive efficiency than did Merinos. Artificial insemination is widespread in the Australian sheep industry so it is important to know if lamb mortality is comparable as with natural mating. This project showed that lamb mortality was similar to natural mating at around 20% with dystocia and starvation-mismothering accounting for 72% of lamb deaths. Therefore artificial insemination can be validly used for sheep reproduction studies. [ABSTRACT FROM AUTHOR]

Data from 2833 unmulesed Merino lambs from 49 sires and 1535 dams that were born from 2005 to 2009, were used to identify indicator traits for breech strike in a Mediterranean environment. Sheep were managed in a normal production environment where no preventative treatments were applied to protect them from being struck by flies, but were immediately treated when found to be fly struck. Seventy-seven skin, body conformation, wool, disease and production traits that may contribute to breech strike and that could qualify as potential indicator traits were recorded on progeny at birth, weaning, post-weaning, yearling, spring and at pre- and post-hogget age at ~18 months of age. In all, 31% of ewes and 22% of rams were fly struck in the breech area between birth and hogget shearing. The heritability of and the phenotypic and genetic correlations between the potential indicator traits and breech strike were estimated. The results showed that breech strike is a heritable trait (h² = 0.51 ± 0.10), and that the most important indicator traits for breech strike were dags, scored at any time, especially at hogget age (rg = 0.81 ± 0.15), spring (rg = 0.77 ± 0.13) or at weaning (rg = 0.64 ± 0.00), urine stain scored at weaning (rg = 0.54 ± 0.13) and marking (rg = 0.51 ± 0.15), neck wrinkle at hogget age (rg = 0.46 ± 0.13) and breech cover (rg = 0.32 ± 0.15) scored at post-weaning shearing. These traits could be used to select indirectly for breech strike resistance in a Mediterranean environment. The present paper reports on a genetic study to identify indicator traits that are heritable and genetically correlated with breech strike in a Mediterranean environment. Dags, urine stain and neck wrinkle have been identified as indicator traits with the best potential to breed sheep indirectly for resistance to breech strike in a Mediterranean environment without the need to challenge animals directly with blowflies. [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]

Currently there is a need for an accurate and non-hazardous method to measure individual intake of a supplement in grazing sheep over a prolonged period. This paper examines the potential of fenbendazole (FBZ) as a marker of intake. The following five experiments aim to determine the relationship between oral ingestion of FBZ and the plasma concentrations of FBZ and its metabolites oxfendazole (OFZ) and FBZ-sulfone (SUL) after single, multiple and daily doses both in housed and grazing sheep and sheep infected with internal parasites. The results from these experiments indicate that OFZ+SUL concentrations in plasma are dependent on FBZ dose rate in housed and grazing animals with differences evident between different dose rates (P < 0.001). Variability of OFZ and SUL concentrations increase in grazing compared with housed animals. Area under the curve of metabolite concentrations was also shown to indicate dose rate regardless of the timing and frequency of dose. Stepwise regressions indicated that sampling every 48 h gave a good representation of area under the curve for different dose rates (R² = 0.951, P < 0.001). A significant separation of treatment means was achieved when samples were taken every 48 h and pooled during daily dosing with FBZ (P < 0.001). Finally gastrointestinal nematode infection did not affect OFZ and SUL concentrations after daily doses of FBZ. The results from these experiments indicate that FBZ is a useful and accurate marker of supplement intake in grazing animals. There is a need for an accurate and non-hazardous method to measure individual intake of supplements in grazing sheep over a prolonged period. The potential of fenbendazole as a marker of intake was examined. The results show that fenbendazole metabolites in plasma are dependent on dose in a range of situations and indicate that fenbendazole is a useful and accurate marker of supplement intake in grazing animals. [ABSTRACT FROM AUTHOR]

Eruption of permanent incisors (dentition) is used as a proxy for age for defining meat quality in Australian sheep meat. However, this approach may not be reliable. While not presently available, an objective method could be used to determine sheep age, and thus sheep category, which would then potentially remove any inaccuracies that may occur in classifying sheep meat product. Statistical classification algorithms have been successfully used in bioinformatics. In this paper we review the performance of three algorithms (support vector machines, recursive partitioning and random forests) for determining sheep age. The algorithms were applied to the measured fatty acid profiles of fat samples from 533 carcasses; 254 lamb (<1 year old), 131 hogget (~1-2 years old) and 148 mutton (>2 years old) samples. Three data pretreatments (range transformation, column mean centering and range transformation with mean centering) were also examined to determine their impact on the performance of the algorithms. The random forests algorithm, when applied to mean-centred data, gave 100% predictive accuracy when classifying sheep category. This approach could be used for the development of an objective test for determining sheep age and category. [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]

Context. Mortality of new-born lambs is well known to have important implications for both animal production and welfare. Improving survival rates by genetic selection is very desirable, but the low heritability of survival traits challenges the prospect of useful genetic gain. Aim. This study aimed to derive genetic and environmental parameters for lamb survival in the Elsenburg Merino resource flock. It also investigated correlations to possible indicator traits birthweight and birth coat score and reported genetic progress in breeding values for lamb survival following 33 years of divergent selection. Methods. The flock was divergently selected for number of lambs weaned and was separated by the High (positive) and Low (negative) selection groups. The pedigree file identified 8138 lambs as the progeny of 273 sires and 2062 dams. The study considered total survival from birth to weaning (Tsv) that was also partitioned into perinatal survival to 3 days of age, and the remaining period. Variance components were derived by linear mixed models by using the ASREML® program. Genetic trends were derived by predicting mean breeding values for selection groups within each year and evaluated by fitting linear and broken-stick regression models. Results. Predicted Tsv of H-line lambs (0.81 ± 0.01) was higher (P < 0.01) than that of L-line lambs (0.68 ± 0.01). Heritability was significant but low for survival traits (0.03-0.07), moderate for birthweight (0.16) and high for birth coat score (0.54). Genetic trends of the H-line trended divergently (P < 0.01) to the L-line for survival traits, but a changepoint (P < 0.01) in trend suggested that the H-line reached a selection plateau following 19-22 years of selection. Preceding this period, the rate of genetic change equalled ~1% of the mean for Tsv. Conclusions. Despite the low heritability of survival, the genetic trends reported in this study contradicted the premise that genetic selection is not a worthwhile method to reduce incidences of lamb mortality. Implications. It is recommended that lamb survival phenotypes should be recorded and incorporated into indices individually where possible, but composite traits are a viable alternative. [ABSTRACT FROM AUTHOR]

Context. Australian sheep breeding values (ASBVs) for the categorical trait of lambing ease are routinely estimated by Sheep Genetics via a threshold model. This has been pedigree-only, and has not utilised genomic information. Aim. The present study aimed to update the genetic evaluation model and parameters for lambing ease for terminal sire sheep (dominated by White Suffolk and Poll Dorset breeds). The model includes correlations with birthweight and gestation length. Cross-validation was used to determine the value of the improved models and the inclusion of genomic information. Methods. New data-preparation pipelines were developed to accommodate improved data-filtering methods and contemporary group construction. Genetic parameters, including correlations among traits, were estimated using continuous and threshold models, with various combinations of effects in mixed animal models. Cross-validation of breeding values was performed against progeny performance, by using forward prediction. Key results. The increased volume of data, improved data preparation steps and enhanced evaluation software now allow a more complex model to be fitted, including maternal, sire by flock-year and genetic group effects, which were significant for all traits, along with the inclusion of multiple sire groups in the pedigree. However, the inclusion of the direct-maternal covariance and sire by flock-year terms resulted in unrealistically inflated estimates of some components, and thus the final covariance matrices required some adjustments. Cross-validation of breeding values was performed against progeny performance using forward prediction. For all traits, the phenotype accuracies and estimated breeding value correlations were higher from the new model without genomics than were those from the current routine evaluation. The benefit from including genomic information based on crossvalidation is minimal currently but is expected to improve as the size of the reference population grows. Further work is required to define acceptable data-quality thresholds for the construction of datasets for routine breeding value estimation. Conclusions. The new model and parameters resulted in ASBVs with an improved predictive ability, with increased accuracy and reduced bias compared with the current analysis. Furthermore, a small increase in accuracy was observed for all traits from utilising genomic information in the model. Implications. The new genetic evaluation procedures and models will be used to update those being applied in the routine Sheep Genetics evaluation system and also support further index development for the terminal sire breeds in Australia. [ABSTRACT FROM AUTHOR]

Context: Herding and mustering procedures during livestock management can be time-consuming, labour intensive, and costly. The ability to gather animals virtually is an enticing notion but technology to do this is not widely commercially available. Aims: The eShepherd® virtual fencing system being developed for cattle may be able to remotely herd animals. This system operates via global positioning system, and requires animals to wear a neckband device. Animals are trained to associate an audio tone with an electrical pulse to avoid a virtual boundary. Methods: Experiments were conducted with cattle using pre-commercial prototypes of the automated virtual fencing neckbands, and with sheep using manually operated dog training collars implementing the same virtual fencing algorithm to explore the potential of this technology for herding, and optimal fence designs for herding success. In the first experiment, five groups of 12 cattle were moved down a 344 m paddock using three different fence placement designs. Results: The most successful design for cattle herding was a back fence that followed behind the animals to prevent them from turning back in the wrong direction. The fences were manually activated by personnel based on the cattle movement. The same type of fence design was manually applied to two groups of six sheep to successfully herd them down a 140 m paddock in the second experiment. Conclusions: All herding was highly dependent on the animal's own pace of movement as no signals were applied to 'push' the animals, the systems only prevented movement back in the wrong direction. The pre-commercial prototype of the automated eShepherd® device used is now obsolete and testing with updated versions would be needed to confirm its application for animal herding. Implications: These preliminary trials indicate potential for virtual fencing technology to herd livestock, but technology improvements are required, and an automated device for sheep is not yet available. Herding and mustering of livestock can be labour intensive and costly. Gathering animals virtually may be economically beneficial but technology is not currently widely commercially available. This study tested the application of pre-commercial prototypes of the eShepherd® virtual fencing system to herd cattle, and manual electronic collars applying the same algorithm to herd sheep. A single back fence that followed behind the animals to prevent movement back in the opposite direction was most successful but further testing with updated technology is needed. [ABSTRACT FROM AUTHOR]

Context. Brazilian sheep production chain includes farms that raise sheep to produce breeding rams and ewes, i.e. stud farms, and farms that raise sheep to breed lambs for meat. However, there are few studies on sheep welfare in Brazil. Aims. To assess the welfare of sheep in Brazil, comparing ewes on stud and meat farms. Methods. Seven stud (S) and 10 meat (M) farms were assessed in the metropolitan regions of Curitiba and Castro, State of Parana, using the Animal Welfare Indicators protocol for sheep. Results of both groups were compared using Fisher's exact test for yes or no questions, Mann-Whitney test for non-normal data and linear mixed models to check each indicator, with significance level at 0.05. Key results. Main characteristics that reduce sheep welfare were low body condition scores (40.6% on both groups), lesions to the legs (S = 45.9%, M = 56.0%), and pain induced by tail docking, with most ewes having a short tail length (S = 79.1%, M = 85.6%). Comparing both groups, ewes from stud farms presented less light faecal soiling (S = 1.3%, M = 27.0%), less faecal soiling and dags (S = 0%, M = 15.7%), better fleece cleanliness (S = 64.8%, M = 19.8%), fewer lesions to the head and neck (S = 3.2%, M = 12.3%), and higher frequency of panting (S = 28.0%, M = 1.5%). Conclusions. We were able to identify the main welfare restrictions in both stud and meat farms, and the hypothesis that welfare is higher on stud farms was not confirmed. Implications. The identification of on-farm welfare concerns as well as the differences between stud and meat farms allows for readily applicable recommendations, tailored to improve welfare within the prevalent sheep-rearing systems in southern Brazil. This experience with the Animal Welfare Indicators protocol for sheep in the Brazilian context may facilitate further studies and implementation of permanent welfare monitoring and action plans. [ABSTRACT FROM AUTHOR]

Context: Growing of dual-purpose crops for grazing by livestock has increased in popularity in the high-rainfall zone of southern Australia, a livestock production zone traditionally based on permanent perennial grass species. Aims: A systems experiment examined the impact on pasture forage availability, sheep grazing days and crop yields when one-third of a farmlet was sown to dual-purpose wheat (Triticum aestivum L.) and canola (Brassica napus L.) crops. Methods: The experiment comprised nine experimental units (farmlets) divided into three treatments with three replicate farmlets per treatment: control farmlets sown to phalaris (Phalaris aquatica L.)-based pastures; and two treatments with grazing of crops prioritised for either ewes or their progeny. Control farmlets comprised four sub-paddocks (0.231 ha each) in 2013 and six sub-paddocks in 2014–2016. Farmlets in treatments that included dual-purpose crops comprised six sub-paddocks (0.231 ha), with two sub-paddocks sown to permanent pasture and the other four sub-paddocks supporting a pasture–pasture–canola–wheat rotation. Key results: Crops were sown in February or early March and grazing commenced by mid-May in all years. Canola was grazed first in the sequence in 3 of 4 years. Treatments had similar total sheep grazing days per year, except for the progeny-prioritised treatment in 2014 when agistment weathers were introduced to utilise excess crop forage. Grazing did not affect wheat yields (3.9 vs 3.7 t/ha, P > 0.05) but did reduce canola yields (3.6 vs 3.0 t/ha, P = 0.007). Pasture availability (dry matter per ha in the pasture paddock at entry by sheep) was higher in the control during late summer and autumn when the crops were being established; however, resting of pastures during late autumn and winter while crops were grazed resulted in no difference in pasture availability among treatments during spring. Conclusion and implications: The key feed-gap is in late summer and autumn when dual-purpose crops are included in the system. Early and timely sowing of crops increases the grazing opportunity from dual-purpose crops before lock-up. Growing wheat plus canola provided some hedge against poor establishment and/or slow growth rates in one of the crops. Growing of dual-purpose crops for grazing by livestock in the high-rainfall zone may allow increased production from a given area of land. Low pasture availability in winter due to cold temperatures may restrict livestock production; however, grazing dual-purpose crops allows pastures to be rested from late-autumn to early spring. The main livestock feed deficit when dual-purpose crops are part of these farming systems is during late summer and autumn when crops are being established, but pastures accumulate biomass while crops are grazed during winter. [ABSTRACT FROM AUTHOR]

Context: African livestock play a critical role in food security and the wider economy, while accounting for >70% of African agricultural greenhouse gas emissions. Accurate estimates of greenhouse gas emissions from livestock are required for inventory purposes and to assess the efficacy of mitigation measures. While there is an increasing number of studies assessing methane (CH4) emissions of cattle, little attention has been paid to small ruminants (SR). Aims: Enteric CH4 emissions were assessed from 1345 SR in three counties of western Kenya to develop more accurate emission factors (EF) for enteric CH4 from sheep and goats. Methods: Using on-farm animal activity data, feed samples were also analysed to produce estimates of feed digestibility by season and region. The combined data were also used to estimate daily CH4 production by season, location and class of animal to produce new EF for annual enteric CH4 production of SR. Key results: Mean dry-matter digestibility of the feed basket was in the range of 58-64%, depending on region and season (~10% greater than Tier I estimates). EF were similar for sheep (4.4 vs 5 kg CH4/year), but lower for goats (3.7 vs 5 kg CH4/year) than those given for SR in developing countries in Intergovernmental Panel on Climate Change (Tier I) estimates. Conclusions: Published estimates of EF for SR range widely across Africa. In smallholder systems in western Kenya, SR appear to be managed differently from cattle, and EF appear to be driven by different management considerations. Implications: The findings highlighted the heterogenous nature of SR enteric emissions in East Africa, but also suggested that emissions from SR are quantitatively less important than other estimates suggest compared with cattle. [ABSTRACT FROM AUTHOR]

Context. The availability of effective indirect rather than direct selection criteria for genetically reducing breech flystrike is crucial for the Australian wool industry, as expression of breech flystrike is routinely suppressed by management interventions to minimise the risks to sheep health, welfare and productivity. Understanding how much genetic gain can be made in reducing breech strike, while also selecting for other key traits is important in choosing breeding objectives, particularly for Merino genetic improvement programs. Aims. We predicted genetic gains from within-flock selection to reduce breech flystrike incidence (FS) and improve productivity under a range of scenarios that all used indirect selection criteria in the genetic evaluation of FS. Methods. Three breeding objectives were modelled, by adding FS as a trait to the breeding objective for the Dual Purpose Plus (DP+), Fibre Production Plus (FP+) and Merino Production Plus (MP+) indexes available from MERINOSELECT. A large range of economic values were examined for FS, from 0 to -$240/strike.sheep per year in $20 increments. For all scenarios, full records of productivity traits and pedigree information were assumed to be available for use as selection criteria, as well as records of breech wrinkle, dag and breech cover scores. Predictions were conducted for scenarios assuming (a) moderate heritability for FS (b) low heritability for FS, and (c) low heritability for FS, but higher heritability for dag score than assumed for scenarios (a) and (b). Key results. After 10 years of selection, under assumption (a) predicted genetic gains in FS ranged from 0, up to maximum reductions of 0.19, 0.21, and 0.20/strike.sheep per year from use of the FP+FS, MP+FS and DP+FS indexes, respectively. Under assumption (b) predictions of genetic gain for FS were considerably lower and ranged from 0 to maximum reductions of 0.04, 0.06 and 0.06/strike.sheep per year based on use of FP+FS, MP+FS and DP+FS indexes, respectively. Under assumption (c), predicted genetic gains in FS were very similar to those under assumption (b). When 70% of the maximum gains in FS studied were targeted, from 70% to 93% of genetic gains in the overall index (excluding FS) were predicted to be retained when FS had moderate heritability, and from 85% to 95% when FS had low heritability. Conclusions and implications. There is a practical range of economic values for FS (from -$60 to -$80/strike.sheep per year for MP+FS and DP+FS indexes and -$60 to -$140/strike.sheep per year for a FP+FS index when the heritability of FS is moderate and -$100 to -$200/strike.sheep per year for a MP+FS index and -$140 to -$240/strike. sheep per year for FP+FS and DP+FS indexes when the heritability of FS is low), that could be used in breeding programs to genetically reduce FS, while retaining competitive levels of genetic gains for other important traits. Reduction of FS is achievable to low levels, after 10-20 years of index selection, similar to levels achieved by mulesing (0.01/strike.sheep per year in average seasonal conditions). [ABSTRACT FROM AUTHOR]

Current Australian ewe management guidelines are based on research from Merino ewes and have been transposed to crossbred ewes. It is unknown whether guidelines developed for Merino ewes are applicable to crossbred ewe production systems. To investigate this, the effect of ewe liveweight and condition score profile during pregnancy on lamb birthweight and survival for Border Leicester × Merino (BLM) crossbreds was compared with Merino ewes. Condition score profiles of 720 Merino and 680 BLM ewes were managed from 50 days after ram introduction to achieve one of four target condition scores at lambing. There were three replicates of the four target condition score treatments and both breeds of ewes were in each plot. By Day 140 after rams in, the BLM ewes were fatter (P < 0.001) and heavier (P < 0.001) than the Merino ewes, despite being managed in the same plots. Liveweight at conception and change in liveweight in late pregnancy of the Merino and BLM ewes had a similar effect on the birthweight and weaning weight of their lambs. However, birthweight and weaning weight of lambs from BLM ewes was less sensitive to ewe liveweight change in early pregnancy. Birthweight survival curves were similar in lambs from Merino and multiple-born lambs from BLM ewes, and the survival of lambs from multiple-bearing BLM ewes responded to manipulation of condition score in a similar pattern to lambs from Merino ewes. Therefore, managing liveweight or condition score of multiple-bearing BLM ewes is likely to improve lamb survival in a similar fashion to lambs from Merino ewes, although the absolute response in survival will be smaller than that achieved in Merino ewes at the same condition score. In addition, it is important to manage liveweight of both single and multiple-bearing BLM ewes during pregnancy to optimise weaning weight of their lambs, as those lambs born to BLM ewes of low liveweight were significantly lighter at weaning. Lamb survival is crucial for welfare and economic performance of prime lamb production systems. Ewe management guidelines for Australian farmers are based on Merinos and it is unknown whether these guidelines are relevant for all ewe production systems. When managed together, crossbred ewes gained more weight and were fatter than Merino ewes; the current guidelines are therefore likely to be overestimating nutritional requirements or under estimating feed intake, however lamb survival will be optimised by managing single and multiple-bearing ewes differentially. [ABSTRACT FROM AUTHOR]

Forty Dorper x Pelibuey crossbred male lambs (31.70 ± 2.30 kg, 4 months of age) were used to evaluate the effect of zilpaterol hydrochloride (ZH; 0 or 10 mg/lamb daily) and soybean-oil (SBO, 0 or 60 g/kg DM) supplementation on intramuscular fat, fatty acid (FA) profiles and cholesterol concentration of their meat. After 34 days, the animals were slaughtered, and their longissimus thoracis muscle was collected. The climatic conditions were of moderate heat stress (average temperature 35.7°C) during the study. Feedlot performance and carcass characteristics were not affected (P > 0.05) by ZH and SBO supplementation. The ZH treatment decreased the intramuscular fat content (by 30.4%), the amount of monounsaturated FA (by 3.5%) and the monounsaturated FA : saturated FA ratio (by 4.9%) compared with the control group. Supplementation with SBO decreased cis FA, C18:1 n-9c and C20:4 n-6, whereas the trans FA and cholesterol concentration increased. ZH use caused a decrease in body fat and intramuscular fat concentration. However, it caused a decrease in total monounsaturated fatty acids, which are among the healthiest fats in terms of the nutritional value of meat. Generally, principal changes in the lipid composition of hair lamb meat under heat-stress conditions were caused by SBO supplementation; however, they would have a minimal negative impact on human health. [ABSTRACT FROM AUTHOR]

The influence of ewe gestation nutrition (EGN) and lamb finishing diet (LFD) on muscle essential fatty acid, antioxidant and mineral status and retail colour of meat in F1 progeny lambs were investigated. First-cross Border Leicester x Merino and Maternal-Coopworth Composite ewes (n = 938) were artificially inseminated to nine terminal sires. From this flock, 648 pregnant ewes were selected between Day41 and Day 49 of pregnancy, producing 72 pregnant ewes from each sire for distribution across six condition-score (CS) groups. Each CS group was balanced for three sires of high, medium and low lean meat yield and ewe breed. Variation in EGN was achieved through pasture allocations and supplementation, to meet threeCS(2.5, 3.0 and 3.5) targets at lambing. At lambing, management ofEGNceased and ewes and lambs were given access to similar pasture allocations. Lambs were weaned at 12 weeks of age and backgrounded on pasture before the random allocation from within each block of sire by CS treatment combination, to the following three different finishing diets: high energy-high protein (HEHP); high energy-moderate protein (HEMP) and moderate energy-high protein (MEHP). Moderate EGN (CS 3.0) increased (P < 0.02) muscle C22:6n-3 and decreased (P < 0.04) C20:4n-6 concentrations compared with CS 2.5 and CS 3.5EGNgroups respectively. Redness of meat over the display period was greater (P = 0.005) forCS3.0 andCS3.5EGNregimes than for theCS2.5 regime. TheMEHPdiet reduced (P< 0.01) muscle C18:2n-6, C20:4n-6 and total n-6 fatty acid and increased antioxidant (vitamin E, P < 0.01) concentrations compared with HEHP and HEMP diets, but iron concentration was not affected. Differences in dietary vitamin E concentration betweenMEHPdiet and HEHP orHEMP diets are likely to have contributed to increases in muscle antioxidant status. The energy and protein concentration of LFD had no effect on the health claimable n-3 fatty acid concentration in meat. [ABSTRACT FROM AUTHOR]

Two small pen trials with cattle and sheep both clearly demonstrated that while there is significant variation in residual feed intake when on high energy supply, there is negligible variation when energy supply is limited. A review of literature demonstrated that this is also the case when energy supply is limited by heat or physiological state, such as peak lactation, and in multiple species. There is little evidence of variation in efficiency of maintenance requirements, growth or lactation. Nor is there strong evidence for large variation in digestibility within breeds, despite some differences between divergent breeds. Thus, the primary source of variation in residual feed intake must be in appetite and, in variable environments, it is possible that those with greater appetite are more resilient during times of feed shortage. [ABSTRACT FROM AUTHOR]

In the past, the adoption of online measurement technologies for measuring carcass and meat quality traits objectively has been low among Australian red meat processors. The aim of the present work was to obtain a greater understanding of Australian processor views on the value of objective online measurement technologies. This was achieved through consultation with 65 Australian processors, to understand which carcass and meat quality traits they considered important to objectively measure and what they thought of current and future technologies. It was shown that beef processors ranked meat colour and tenderness as the most important traits (P < 0.001) to objectively measure online. Sheep processors ranked tenderness, pH, age, meat colour, total tissue depth at the 12th rib 110 mm from the midline (GR) and saleable meat yield percentage as the most important traits (P < 0.001) to objectively measure online. The overall processor responses indicated that there is support for online measurement technologies, with 80% of processors stating that online objective grading systems have a role in the Australian meat processing sector now and 88% considered these to have a role in the future. Much can be learned from the implementation of previous online objective measurement technologies by processors in terms of commercialisation and adoption strategies. The development and adoption of objective online measurement technologies is challenging and complex. However, increased adoption of online measurement technologies has the potential to achieve benefits to the whole of industry and needs continued support, coupled with new approaches to enhance adoption. [ABSTRACT FROM AUTHOR]

The aim was to obtain experimental evidence of cervical collagen degradation in anoestrous Corriedale adult ewes induced to ovulate with progesterone (P) and gonadotrophin-releasing hormone (GnRH), at the expected time of induced ovulation and early luteal phase. In Experiment 1, anoestrous ewes were treated with P for 10 days (P, n = 4), with nine micro-doses of GnRH followed by a GnRH bolus injection (GnRH, n = 4) or with P plus GnRH treatments (P+GnRH, n = 3), and cervices were obtained either without treatment (A, n = 4), when P was removed, or 24 h after the GnRH bolus injection. In Experiment 2, cervices were obtained 1 (group P+GnRH, n = 5) or 5 (P+GnRH 5, n = 6) days after the GnRH bolus injection withPpretreatment.MMP-2activity was detected in all samples; however,MMP-9activity was only detected in 15% of the samples. The activity of the latent (L) form of MMP-2 in the cranial zone of group A was higher than in the cranial zone of groups P, GnRH and P+GnRH, and was also higher than that in the caudal zone of the same group (P < 0.05). The collagen concentration was lower in group P+GnRH 1 than in group P+GnRH 5 (P < 0.04). The activity of the activated (A) form of MMP-2 and the A/L MMP-2 ratio were higher in group P+GnRH 1 than in group P+GnRH 5 (P < 0.05). Data suggest that the L form of MMP-2 was expressed mainly in a constitutive form in the cervix of anoestrous ewes and that an oestrogen-dependent activation mechanisms due to theGnRHtreatmentmaybe responsible for the lowest collagen content at the moment of the induced ovulation. This work provides evidence about cervical collagen remodelling in anoestrous ewes treated with P + GnRH.EN [ABSTRACT FROM AUTHOR]

Three bedding materials, sawdust, rice husk and double layer of sawdust used during transportation to slaughterhouse were compared. Sixty light male lambs of Merino breed were used in the present study. Welfare physiological indicators (glucose, lactate, creatinine, lactate dehydrogenase, creatine kinase, cortisol and catecholamine) sampled before and immediately after the transportation, and carcass microbial quality (total viable counts, Enterobacteriaceae and Pseudomonas spp.) in three different sites of carcass (rump, flank and neck) were assessed. Bedding material during transport did not affect any of the physiological indicators analysed, except for creatinine, which was lower in lambs transported with rice husk. Bedding material had no effect on carcass microbial quality. Sampling site affected values of Enterobacteriaceae and Pseudomonas spp. The lowest values for Enterobacteriaceae count were found in the neck, while Pseudomonas spp. presented the highest count in the flank site. In conclusion, under the conditions of the present study, all substrates tested could be recommended as bedding material during transport, without showing significant differences on animal-welfare indicators or carcass microbiological quality. [ABSTRACT FROM AUTHOR]

This review provides an update on recent research into the effects of maternal nutrition on fetal biology and the growth, development and productivity of progeny in postnatal life of ruminant livestock. Evidence is summarised for effects on postnatal growth and body composition, feed intake and efficiency, carcass characteristics and meat quality, wool production, reproduction and lactation performance. In general, these demonstrated effects are not large in relation to the effects of postnatal nutrition and other environmental influences. The mechanisms underpinning the above production outcomes are briefly discussed in terms of systemic endocrine and metabolic responses, and cellular and molecular effects in skeletal muscle, bone, adipose tissue, wool follicles and brain of fetal, neonatal and adult progeny. Treatments observed to elicit tissue responses include maternal under- and overnutrition at various stages of pregnancy and placental insufficiency caused by increased litter size, chronic maternal heat stress and premating carunclectomy in sheep. The as yet meagre evidence for epigenetic mediation of intergenerational effects in ruminants is considered, as is the likelihood that other, more conventional explanations may suffice in some cases. Finally, evidence is summarised for the proposition that the placenta is not merely a passive conduit for nutrient transfer from dam to fetus, but plays an active role in buffering the effects of variations in maternal nutrition on fetal growth and development, and thence, postnatal outcomes. [ABSTRACT FROM AUTHOR]

An intra-rumen (IR) gas-sensing system incorporating commercially available gas sensors [methane (CH4), carbon dioxide (CO2) and hydrogen (H2)] and a wireless sensor network was developed to measure rumen gas concentrations of grazing animals in real-time. The IR gas-sensing devices also measure temperature and pressure near the sensors and the design isolates the electronics and battery from exposure to gases. Membranes were developed that allow the desired gases to diffuse through to the sensors while excluding corrosive hydrogen sulfide (H2S). Performance of the prototype IR devices was tested in cattle and sheep fed once a day as a proof-of-concept. Concentrations of expired gases from respiration chambers were compared with the concentrations obtained by the IR gas-sensing device within the rumen digesta. Direct measurements of rumen gas cap samples demonstrate a similar gas profile to that observed with the IR gas-sensing device with the ratio of CO2 : CH4 peaking shortly after feeding and CO2 levels nearly 2.5 times greater than those of CH4. The gas ratio then declines over time to a point when at 23 h post-feeding the concentration of CH4 exceeds that of CO2. The H2 gas concentration in the rumen varied throughout the day reaching maximum levels of 2500 ppm after feeding and declining to 250 ppm over the day. Although the IR device was able to detect H2 in the rumen throughout the entire day, expired H2 was often below the limits of detection in the respiration chamber. Current work is focussed on extending the longevity of the devices in the rumen so that replicated trials can be performed on the accuracy and precision of the measurements. [ABSTRACT FROM AUTHOR]