EB_DESIGN_OPTIMATION_AB_PROGRAMMES_2004_90

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Chapter 1 Introduction (Based on Bijma and van Arendonk, 2004) There are two fundamental questions faced by animal breeders. The first asks: “What is the best animal?” Is the best Labrador the one with show-winning conformation or the one with exceptional retrieving instinct? Is the best dairy cow the one that gives the most milk; the one with the best feet, legs and udder support; or the one that combines performance in these traits in some optimal way? These are matters of intense debate among breeders, and, in truth, no one has all the answers. The question is an important one, however, because the answers determine the desired direction of genetic change for breeding organisations and people keeping farm or companion animals. The second question asks, “ How do you breed animals so that their descendants will be, if not “best”, at least better than today’s animals?” . In other words, how can we genetically improve animal populations? This question involves genetic principles and animal breeding technology, and is the subject of this course.

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1. What is the best animal “Best” is a relative term. There is no best animal for all situations. The kind of animal that works best in one environment may be quite different from the best animal under another set of circumstances. When we describe animals, we usually characterize them either in terms of appearance or performance or some combination of both. In any case, we talk about traits . A trait is any observable or measurable characteristic of an animal.

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Some examples of observable traits –traits we would normally mention in describing the appearance of an animal- are coat color, size, muscling, leg set, udder conformation, and so on. Some examples of measurable traits –traits we would likely refer to in describing how an animal has performed- are body weight, daily milk production, time to run a mile, etc. There are hundreds of traits of interest in domesticated animals. Note that in none of the examples of traits mentioned above is the appearance or performance of a particular animal described.

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An animal may be red and weigh 343 kilograms at 1 years of age, but red coat color and 343 kg yearling weight are not the traits- the traits are simply coat color and weaning weight. Red and 343 kg are the observed categories or measured levels of performance for the traits of coat color and yearling weight. They are the phenotypes for these traits.

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In animal breeding, we are mainly concerned with changing animal populations genetically. From a genetic point of view, therefore, we want to know not only the most desirable phenotypes, but the most desirable genotypes as well. That is because an animal’s genotype provides the genetic background for its phenotypes and it is the genetic material that is passed on from parents to its offspring. Summarized in an equation: P = G + E

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countries. And at the other end we have an increasing number of poultry selection lines that are discarded when yet another independent poultry breeding company is taken over by a larger and often multinational breeding company.

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7. Technology and animal breeding The face of animal breeding has changed significantly over the past decades. Animal breeding used to be in the hands of a few distinguished “ breeders”, individuals who seem to have specific arts and skills to “ breed good animals” . Nowadays, breeding in particular in livestock species is dominated by science and technology.

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In some livestock species, animal breeding is in the hands of a few large companies , and the role of the individual breeders seems to have decreased. There are several reasons for this change. Firstly, the breeding industry has adopted scientific principles . Looking was replaced by measuring, and an intuition was partly replaced by calculations and scientific prediction. Other major developments grew from the introduction of biotechnology.

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Biotechnology can be broadly defined as the application of biological knowledge to practical needs . These technologies fall generally into two categories, reproductive and molecular. Not all of this is new. Artificial insemination was introduced in cattle in the fifties. There is no doubt that technology had a major impact on rates of genetic improvement in dairy cattle and is just as important to the structure of animal breeding programs. Nowadays, technologies like ovum pick up, in vitro fertilization, embryo transfer, cloning of individuals, and selection with the use of DNA-information is all on the ground.

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Some of the technologies are already applied, others are further developed, or waiting application. Finally, rapid development of computer and information technology has greatly influenced data collection and genetic evaluation procedures in animal populations, now allowing comparison of predicted breeding values across farms, breeds or countries.

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It is important to recognise that the introduction and exploitation of new technologies have large social impacts . The introduction of breeding methods typically needs to find the right balance between what is possible from a technological point of view and what is accepted by the decision makers and users within the socio-economic context of the production system.

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Ultimately it is the consumer who decides which technology is desirable and which is not. In most western societies, consumers are increasingly aware of health, environmental and animal welfare issues.

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Food safety and methods of food production are part of their buying behaviour. However, price and production efficiency are still major factors determining the sustainability of a livestock sector. Successful animal breeding programs need to find and apply the accepted technologies that help them remain competitive . This course is mostly concerned with the technical issues involved in the application of new technologies in animal breeding.

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8. Components of breeding programs Very generally, the aim of animal breeding is to genetically improve populations of livestock so that they produce more efficiently under the expected future production circumstances . Genetic improvement is achieved by selecting the best individuals of the current generation and by using them as parents of the next generation .

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A breeding program is the organized structure that is put into place to genetically improve livestock populations. This chapter deals with the set-up and evaluation of animal breeding programs.