New trends in livestock breeding

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Dr Japie van der Westhuizen, SA Stud Book

he information revolution brought about by the internet and with it amazingly accurate and fast search engines, has resulted in the accumulation of knowledge unsurpassed by anything before. What have been hailed in livestock breeding as good observations and conclusions in the past, are now either proven, rejected, or even put to better use in breeding programmes.

The forefront focus during the 1960s to 1980s was on functionality of farm animals, their anatomy and physiological processes that underpinned suitability in specific environmental and production systems. It was also the era known to be the onset of computer database developments and with those, objective measurements and recordings of economically important traits. It was the dawn of big data and the proper use of mathematical models to predict the genetic merit of candidates for selection of parents of the new generation production animals. Although the theory of mixed model methodology to calculate best linear unbiased prediction (BLUP) breeding values was already developed, the practical application thereof had to wait for computing power to catch up. This mainly happened in the late 1980s and early 1990s before it could be put to full use. The very effective and accurate genetic merit predictions, relying on breeders to accurately record parentage and objectively measured traits (within well-defined contemporary groups), immediately caused a new set of challenges. Effective genetic selection without well-defined long-term breeding objectives, especially in its simple form that favours only a few traits, mainly led to strict within family selection and high inbreeding of progeny and, in many cases, unfavourable correlated responses for other economically important traits. The traits that mostly suffered from these practices are

female fitness traits, such as reproduction and survivability (or sometimes referred to as ‘involuntary culling’). Again, although the theories associated with the setting up and application of breeding and selection objectives were well established, the combination thereof with BLUP breeding values only started taking off in this century when scientists and breeders realised the damages caused by single trait selection in all its forms.

Basic accurate recording is always a prerequisite for any breeding programme This more balanced approach and carefully constructed mating programmes assisted scientists and informed breeders to achieve breeding goals that favour animals with the preferred genetic merit to produce offspring that will excel in being more profitable, given the environmental constraints, production system and market …

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