Livestock Matters - Spring 2018

Bull selection should always include consideration of its Estimated Breeding Values SPRING 18 ISSUE LIVESTOCK MATTERS 8 BUL L SE L ECT ION rear a calf. They include 200 day milk, calving interval, age at first calving, longevity and the ease with which they themselves will calve down. “A 2015 EBLEX review showed that the beef industry had made significant financial gains with improvements in genetics over the years, but that these gains were mainly down to improvements in terminal traits. Unfortunately, selecting solely for these traits can have a negative knock-on effect for maternal traits. “So the short term decision to select a bull which will produce a good carcase at the abattoir can mean that in the long term, maternal aspects of performance are getting left behind. “Historically a similar process happened in the dairy industry with animals being heavily selected for production traits at the expense of health and fitness traits, such as fertility. Now though, all aspects are considered, creating dairy cows which are productive all-round and inevitably more profitable in our systems. “So when looking for a bull to sire heifer replacements, some consideration of maternal traits is needed. “There are reasons which may explain why maternal traits have been considered less in the past. One reason is that they tend to have lower reliabilities than those of terminal traits. This is because maternal traits are often poorly heritable, and consequently environmental factors have a larger impact on that traits variation. It can also take a lot longer to get the relevant data back for maternal traits, and also these will only come from the female proportion, limiting the data further. For instance, a bull is likely to be 6 years of age before there is feedback on the age at first calving of its daughters. “So some people ignore maternal traits as they look unreliable, compared with the terminal traits. But a study done by the SAC in 2010 showed that even at 50% reliability, maternal trait EBVs were predictive of performance and good enough to aid decision making. “The study went on to demonstrate that even bulls with maternal EBVs of less reliability than this, when followed through their lives, remained at a similar level of ranking among other bulls in later years. Young bulls considered to have comparatively good maternal traits were often still considered to be comparatively good later on when more reliable. “Another reason for less consideration being given to maternal traits has been their lack of availability. Fortunately this has improved over time. More maternal traits are now being measured and available to commercial producers to aid decision-making. Some breed societies are further ahead with this than others. AI-ing instead of buying? “Choosing proven bulls with good maternal traits may require switching to purchasing semen straws and AI-ing some of the herd. (See pages 15-16 in this issue for information on the FarmSkills DIY AI courses). “AI can give affordable access to bulls of higher genetic merit, and also without the risk of bringing in infectious or venereal diseases. Furthermore, AI provides the flexibility of choosing different straws for different desired outcomes, a cost-effective way to act on breeding decisions rather than invest in multiple bulls. “AI, using a bull selected for its maternal traits, could just be used for heifer replacements and would extend the longevity of the terminal bull(s) in the herd. “AI can also be used in conjunction with synchronisation. This not only gives greater control on the timing of inseminations enabling calving blocks to be tightened, but it also makes it easier to plan the visits by external AI services.” Future developments More and more dairy farmers are utilising the breeding technology of genomics as a tool to increase their genetic progress. This has been through increased uptake in using genomic bulls for AI, as well as genomic-testing of heifers in the herd to help with breeding decisions early on in life. Ben explains: “Genomics has been a massive breakthrough as it cuts out time - a hair or tissue sample from a new-born calf is enough to yield reliable information about the future performance of that animal. “For the beef industry, genomics will mean traits that are difficult to measure can be made much more widely available at an improved reliability. This will include maternal traits along with other more recently discussed traits such as feed efficiency and information on primal cuts. While behind at the moment, the beef sector is developing in this area with genomic EBVs now commercially available for some bulls. ‘Horses for courses’ “When selecting a bull to put to a group of cows or heifers, farmers need to consider whether the offspring will be finished for meat, or be staying in the herd as replacements. “Does the bull need to be an ‘all-rounder’ or does herd size and management allow the selection of some bulls just as terminal sires, and others for breeding the next generations ? Does AI have a place in this breeding management ? ” Ben adds: “Either way, active decisions looking at your desired outcome should be guided by using EBVs as an additional tool, along with all the other information at your disposal.” Synergy Beef Discussion Group ‘Making objective breeding decisions’ was the subject of a recent meeting of Synergy Farm Health’s Beef Discussion Group. Meetings are held every six months and members are being invited to take part in a benchmarking project. This measures Key Performance Indicators and allows participants to see where and how to improve the performance and profitability of their suckler herds. A bull that’s an all-rounder ? Or one selected for its good maternal traits ? Or terminal traits ?