Relationships between clean fleece weight, reproduction and fatness in adult Merino ewes and growth, fleece, carcase attributes and survival in their progeny

Concerns that high clean fleece weight (CFW) sheep were likely to be less fit during drought has been expressed by producers and has been supported to some degree by animal house experiments. These experiments predominantly used dry sheep, and found high fleece weight genotypes were leaner and had lower circulating energy levels. Conclusions from the experiments implied that reductions in reproduction will occur as a result of an emphasis on CFW selection. This thesis has examined the hypothesis that breeding ewes, selected for high or low CFW and high or low body weight and held at two levels of stocking rate, will partition nutrition differently with reductions evident in body fat and reproduction for high CFW animals. Also examined were the effects on carcase quality and growth in their offspring. Adult ewes (5-8 y.o.) were selected on the basis of their hogget CFW and hogget offshears body weight (BWT). Over two years, adult ewes were held at two levels of stocking rate throughout pregnancy and from marking to joining and liveweight, body fat score, ultrasound scanned fat and muscle depth and reproduction were recorded. The first drop of wether progeny were retained for slaughter to determine the effects on carcase quality and the first drop of ewe progeny were retained for measures of hogget fleece production. The final experiment examined controlled feed intake and metabolic energy reserves in the dams under animal house conditions, and the implications for rearing twin lambs

Sheep Updates 2005 - Part 4

This session covers twelve papers from different authors: REPRODUCTION 1. Is it worth increasing investment to increase lambing percentages? Lucy Anderton Department of Agriculture Western Australia. 2. What value is a lamb? John Young, Farming Systems Analysis Service, Kojonup, WA 3. Providing twin-bearing ewes with extra energy at lambing produces heavier lambs at marking. Rob Davidson WAMMCO International,, formerly University of Western Australia; Keith Croker, Ken Hart, Department of Agriculture Western Australia, Tim Wiese, Chuckem , Highbury, Western Australia. GENETICS 4. Underlying biological cause of trade-off between meat and wool. Part 1. Wool and muscle glycogen, BM Thomson, I Williams, University of WA, Crawley, JRBriegel, CSIRO Livestock Industries, Floreat Park WA &CRC for the Australian Sheep Industry, JC Greeff, Department of Agriculture Western Australia &CRC for the Australian Sheep Industry. 5. Underlying biological cause of trade-off between meat and wool. Part 2. Wool and fatness, NR Adams1,3, EN Bermingham1,3, JR Briegel1,3, JC Greeff2,3 1CSIRO Livestock Industries, Floreat Park WA 2Department of Agriculture Western Australia, 3CRC for the Australian Sheep Industry 6. Genetic trade-offs between lamb and wool production in Merino breeding programs, Johan Greeff, Department of Agriculture, Western Australia. 7. Clean fleece weight is no phenotypically independent of other traits. Sue Hatcherac and Gordon Refshaugebc aNSWDPI Orange Agricultural Institute, Orange NSW 2800 bUNE c/- NSWDPI Cowra AR&AS Cowra NSW 2794 cAustralian Sheep Industry CRC. 8. When you\u27re on a good thing, do it better: An economic analysis of sheep breed profitability. Emma Kopke, Ross Kingwell, Department of Agriculture, Western Australia, John Young, Farming Systems Analysis Service, Kojonup, WA. 9. Selection Demonstration Flocks: Demonstrating improvementsin productivity of merinos, K.E. Kemper, M.L. Hebart, F.D. Brien, K.S. Jaensch, R.J. Grimson, D.H. Smith South Australian Research and Development Institute 10. You are compromising yield by using Dust Penetration and GFW in breeding programs, Melanie Dowling, Department of Agriculture, Western Australia, A. (Tony) Schlink, CSIRO Livestock Industries, Wembley, Johan Greeff, Department of Agriculture Western Australia. 11. Merino Sheep can be bred for resistance to breech strike. Johan Greeff , John Karlsson, Department of Agriculture Western Australia 12. Parasite resistant sheep and hypersensitivity diarrhoea, L.J.E. Karlsson & J.C. Greeff, Department of Agriculture Western Australi

Psychosocial factors associated with outcomes of sports injury rehabilitation in competitive athletes: a mixed studies systematic review.

The prime focus of research on sports injury has been on physical factors. This is despite our understanding that when an athlete sustains an injury it has psychosocial as well as physical impacts. Psychosocial factors have been suggested as prognostic influences on the outcomes of rehabilitation. The aim of this work was to address the question: are psychosocial factors associated with sports injury rehabilitation outcomes in competitive athletes?Mixed studies systematic review (PROSPERO reg.CRD42014008667).Electronic database and bibliographic searching was undertaken from the earliest entry until 1 June 2015. Studies that included injured competitive athletes, psychosocial factors and a sports injury rehabilitation outcome were reviewed by the authors. A quality appraisal of the studies was undertaken to establish the risk of reporting bias.25 studies were evaluated that included 942 injured competitive athletes were appraised and synthesised. Twenty studies had not been included in previous reviews. The mean methodological quality of the studies was 59% (moderate risk of reporting bias). Convergent thematic analysis uncovered three core themes across the studies: (1) emotion associated with rehabilitation outcomes; (2) cognitions associated with rehabilitation outcomes; and (3) behaviours associated with rehabilitation outcomes. Injury and performance-related fears, anxiety and confidence were associated with rehabilitation outcomes. There is gender-related, age-related and injury-related bias in the reviewed literature.Psychosocial factors were associated with a range of sports injury rehabilitation outcomes. Practitioners need to recognise that an injured athlete's thoughts, feelings and actions may influence the outcome of rehabilitation

Extreme ewes: Fleece weight selection - wool, lambs or meat?

The negative genetic correlation between clean fleece weight (CFW) and fat depth (Fogarty et al. 2003) is under investigation. Adams et al. (2004) found that as CFW increased, the ability of Merinos to store fat declined under low and moderate feed conditions. The biological impact of reduced body fat during times of nutritional stress is likely to extend to various aspects of reproduction, including fertility, lamb survival, lamb weight (Cloete et al. 2004) and meat quality (Pethick et al. 2005). This paper reports the responses to a regime of restricted feed intake among ewes selected for high (H) and low (L) CFW and (H) and low (L) bodyweight (BWT), after 8 months of treatment

Mating Conditions and Management Practices Influence Pregnancy Scanning Outcomes Differently between Ewe Breeds

Sheep production in southern Australia may vary by breed, time of year, production output (wool, meat, or both), region and seasonal influence. Sheep producers with flocks of approximately 300–500 ewes (n = 58) were recruited across southern Australia to take part in a survey and mating variables were collected from over 30,000 ewes between October 2020 and August 2021. A Bayesian Network (BN) was developed to identify the interrelatedness and most influential variable on pregnancy and fetal number (of pregnant ewes) outcomes under different scenarios. The BN analysis indicated a low association between the variables explored, however, were breed dependent. In wool-based breeds a mating liveweight of 60–69.5 kg predicted the lowest non-pregnant and greatest number of fetuses, and in shedding ewes 70–79.5 kg predicted the lowest non-pregnant rate and 90–99.5 kg the greatest number of fetuses. Pregnancy rate and fetuses per ewe were optimized at ram percentages of 1.5% for Composite and Merino ewes and 2% for Maternal ewes. A mating BCS 4 resulted in greatest pregnancy rate and number of fetuses across all breeds. Curvilinear relationships between mating liveweight, BCS and ram percentage were observed with pregnancy rate and fetal number. Practically, reproductive potential is best managed on a breed basis and with consideration of all variables explored

The impact of clean fleece weight and bodyweight selection in Merinos on meat traits in the progeny

The carcasses of 136 Merino wether lambs from a single bloodline were studied to determine the impact of phenotypic selection for clean fleece weight (CFW) and bodyweight (BWT) on meat quality characteristics. The lambs were the progeny of sires and dams that were selected for high or low CFW and high or low BWT using hogget phenotypic data, where the dams were managed at 10 or 15 dry sheep equivalent/ha during gestation and from marking to weaning. Maternal stocking rate was found to have no significant effect on any meat traits, except to reduce fatness in high BWT lambs. Phenotypic BWT selection increased hot carcass weight and decreased fatness, lowered temperature at pH 6.0, and showed considerable variation in LDH activity and the ratio of LDH to isocitrate dehydrogenase. It is clear from this study that the stocking rate of the dam during gestation and lactation, and her selection on the basis of CFW or BWT phenotype had no large negative impact on the meat traits of her male progeny

Fat depth, muscle depth, fat score and wool growth in Merino dams selected for high or low clean fleece weight and bodyweight

Concerns exist that selection for increased clean fleece weight (CFW) is expected to reduce body fatness. Such an effect is likely to impact on reproduction; however, all previous studies have examined non-reproductive yearlings or hoggets. The present study, using adult reproductive dams examined the impact of phenotype [based on high or low phenotypic CFW and bodyweight (BWT) performance], stocking rate (high or low) and litter size on body composition and wool traits. High CFW dams were heavier (

Does phenotypic selection for fleece weight reduce lamb survival?

A two year field experiment studied the impact of phenotypic selection for clean fleece weight (CFW) on 'whole ewe' performance using highly fecund medium wool Merinos stocked at either 10 or 15dse/ha. Post-mortem autopsy was undertaken on all lambs found dead (25%) during lambing in each year. Of those lambs with stomachs present for post-mortem, 92% had not fed. Birthweight and birth type significantly affected post-natal mortality and dystocia was responsible for 61% of all deaths. Fat score at mid-pregnancy was significantly and positively associated with post-natal mortality. Fat score in late pregnancy had a significant negative relationship with birthweight. CFW phenotype did not affect fat score at mid-pregnancy or post-natal mortality (P = 0.059)

Long-term liming changes pasture mineral profile

Abstract There is limited information on changes of pasture mineral concentrations over the long-term in response to liming. A long-term field experiment was conducted to assess the influence of lime application on (a) changes in pasture mineral composition over time; and (b) key pasture mineral concentrations and ratios important to animal health. Perennial and annual pastures with or without lime application were sampled annually over 12 years and analysed for macro- and micro-minerals. Mineral ratios and indices were calculated to assess the potential impact on animal health. Liming increased the concentrations of calcium, sodium and silicon, but decreased the concentrations of micro-nutrients including copper, zinc and manganese. The same trend was found in both annual and perennial pastures although there were some fluctuations between years. Liming increased the calcium:phosphorus ratio and the dietary cation–anion difference but reduced the tetany index on both annual and perennial pastures. These findings suggest a potential benefit to improve animal health outcomes for some disorders on the limed pastures. However, the reduced concentrations of some trace elements following liming potentially decreases antioxidant capacity and requires further research

A Cross-Sectional Study of Commercial Ewe Management Practices for Different Sheep Breeds across Southern Australia

The management of ewes across southern Australia may vary with breed and can change over time and, as such, a greater understanding of producer management practices and the motivations that influence these practices is required. A cross-sectional study was performed by telephone interview with sheep producers managing Composite, Maternal, Merino or shedding ewe breeds mated in either spring, summer, or autumn. The surveyed producers were a unique subset of southern Australian producers. A large proportion of the surveyed producers followed current best practice guidelines for ewe mating and lambing nutritional management; however, some producers did not align with these targets. Further, some producers did not see the value in attaining the current recommendations. Pregnancy scanning was widely practiced, likely an artefact of the recruitment process; however, a few producers did not utilize this information for nutritional management at lambing time. Finally, most producers were active in their search for new information, seeking information regularly from a wide range of sources and reported making management changes within the last five years. Further work is required to understand why some producers are not adopting best practice where possible and to understand current barriers for adoption. Management guidelines for all sheep breeds are required to best manage sheep across southern Australia