In an article published in the Journal of Animal Science (2005), Kanis, Greef, Hiemstra and Arendonk discuss this very issue. With concerns about the undesired side-effects of selection for high production efficiency on animal health and welfare and the effects pig production is having on the environment, this article, ‘Breeding societally-important traits in pigs’, highlights the increasing importance of examining and refining the goals that breeding companies are working towards.

Many traits have no economic value within a breeding programme and thus, some would argue whether taking these aspects into account is worthwhile.

However, although not currently economically efficient, reducing the detrimental effect pigs have on the environment or improving the welfare of the animals being produced are major issues in the public’s (and producer’s) eyes and, therefore, such issues should not be ignored.

The inclusion of these societally-important traits into a sustainable breeding programme depends on their genetic aspects (i.e. heritabilities) and their relative economic/noneconomic values. The value of the trait is dependent on a number of issues including the husbandry conditions and the current market situation. For example, the burden of pig manure on the environment will be greatly dependent on its demand by crop farmers and thus when manure is in high demand, high feed efficiency will become solely important for its economic aspects and not its environmental aspects.

Kanis et al. (2005) stress that many societally important traits seem sufficiently heritable to be effectively included in a selection programme. Table 2 indicates the levels of heritability found for a variety of societally-important traits by various authors (as cited in Kanis et al., 2005)

Although in other species, behavioural traits such as feather-pecking and stereotypies have been found to be heritable, the heritability of similar traits and other welfare related traits in pigs are not known precisely enough for application in breeding programmes. The same is true of their genetic correlations with other (economic and non-economic) traits. Kanis et al. (2005) also highlight the possibility of major genes being involved and the potential for accurate DNA markers to become available to test for favourable alleles of some of these traits.

One of the difficulties of applying noneconomic traits to a breeding programme is their ability (or lack of it) to be quantified. Finding out how much more value pork from pigs with better welfare or health is not as easy as asking how much more consumers will pay. And then allocating a value to a potential enlargement in market share associated with improved visible pork characteristics is by no means accurate.

The practicality of breeding companies selecting for societally-important traits is fairly low considering that many of those traits are not yet clearly defined, their heritabilities and genetic variances are often unknown, and the recording of such traits may be problematic and subjective. However, with public concerns regarding animal welfare and the environment growing and continual legislation changes, these societally-important traits may become increasingly important and there may come a time where such traits as aggression and stereotypies may become as important as growth rates in terms of selection traits.

Reference:

E. Kanis, K.H. De Greef, A. Hiemstra & J.A.M. van Arendonk. Breeding for societally important traits in pigs. J. Anim Sci. 2005 83: 948-957.

Source: ACMC - March 2006

- March 2006- March 2006