6 days ago

Sheep Matters_Aug-Sept 17 (redesigned)

Sample copy of new publication aimed at the progressive farmer and professional in the UK sheep industry. For further information and to register your interest go to

What does the future

What does the future hold? A recent study funded by AHDB concluded that the potential value of genetic improvement to health and welfare is not currently being realised in the UK (1). A focus for the future development of new EBVs will be around hard-to-measure traits, such as disease resistance (e.g. resilience against worms) and ease of management (9). SRUC is completing research on ewe longevity. It is expensive and environmentally demanding to replace breeding ewes, so genetic solutions to increase their ‘productive lifespan’ on farm are likely to have financial benefits. Aiming to establish the genetic factors that control longevity and hence productivity should allow new EBVs to be developed (10). EBLEX estimated that by reducing replacement rates (currently standing at an average of 20-25%) and cull rates, over £4M could be saved by the UK sheep industry. BUSINESS IMPACTS MATURE SIZE MATERNAL GROWTH HEALTH* CARCASE Leaner carcasses taken to heavier weights without addition of fat. More carcasses meet specification. Reduced labour costs. Reduced veterinary / treatment costs. Increased lamb survival. Increased ewe survival. Heavier lambs. Faster growth rates & finishing time. Time sales to hit better prices. Reduced days to slaughter store lambs. Increased lamb survival. Faster growth rates & finishing time. Times sales to hit better prices. Faster growth rates & finishing time. Time sales to hit better prices. Reduced feed costs. Increased likelihood of heaviness. WHICH EBV? POSITIVE EBV SCORE Muscle depth (mm) CT lean weight (kg) CT gigot muscularity (kg) Lambing ease (%) Birth weight (kg) Maternal ability (kg) Litter size (kg) 8-week weight (kg) 21-week scan weight (kg) 21-week scan weight (kg) Mature size (kg) 12 AUGUST & SEPTEMBER 2017

Research by SRUC and Signet has also focused on the heritability of lamb survival. A lamb survival EBV could help breeders to improve the resilience of young animals by selecting for genes that affect survivability. This could increase the productivity of commercial herds (11). NEGATIVE EBV SCORE Fat depth (mm) CT fat weight (kg) Want to know more? A word of caution: Nature or Nurture? Different traits have different levels of heritability across different breeds. For example, it is estimated that footrot resistance in ewes is heritable at 10- 20% (7). And genes express themselves differently in different environments (8). Many factors, therefore, need to be taken into account when developing breeding objectives. Once breeding goals are identified it is possible to decide which EBVs will best help to achieve these goals. It is also possible that significant improvements in productivity can be made by changing non-genetic factors such as nutrition. Worm resistance *Health EBVs not available for all breeds Genetic & environmental interaction Genes interact with a whole range of other factors. The breeding potential of an individual animal will only be realised under good management (e.g. nutrition, health and welfare monitoring EBV accuracy EBVs that are based on limited data are adjusted down towards the average. As more data are collected the EBV may increase. An EBV accuracy value is a good indicator of the likelihood that a ram’s EBV will change over time. The higher the accuracy value (0-99), the more is known. 2017 AUGUST & SEPTEMBER 13

Sheep Matters - August/ September 2017