2013GlobalTechBanner786Managing Variation to Achieve Uniformity

Nick Boddicker, Ph.D

Genesus, Inc.

Many packers utilize payment methods that require producers to ship pigs that meet certain targets in order to maximize income from their pigs. These targets are largely centered around slaughter weight and lean yield. If a pigs weight is too light it is discounted. If a pig is too fat it is discounted. In order to receive the most money for a group of pigs the producer wants the largest number of pigs (ideally all of them) to fall within the “sweet spot” where there are no discounts and possibly some premiums. To achieve this, the producer needs to ship a group of pigs that are uniform. Every producer is fully aware that variability in a group of pigs at the packing plant directly affects the check they receive. However, in order to achieve uniformity, variation needs to be appreciated and understood. Variation is evolutionally important and critical for survival of living organisms. Variation exists so that living things can adapt and evolve to their surroundings. Without variation in a population, a single disease could completely wipe out an entire species. Without variation different breeds of pigs would not exist. Without variation, genetic improvement of important traits such as feed efficiency, number born alive, or population health would be impossible. The point is, variation is essential to genetic improvement, but needs to be managed in order to maximize returns, specifically when it comes to shipping pigs to the packing plant. When looking at a group of pigs of the same age, it is easy to see differences in weight, body condition, and soundness. Simply put, this is variation and is driven by 2 things, genetics and environment. Environmental variation is the affect of feed, management, disease, etc. There are a number of things that can be done to reduce or manage environmental variation, including sorting, stocking density, access to water and feed (Buhr 2008, Patience et al., 2004). This article will focus on the genetic aspect of variation. As previously stated, variation is essential in order to make genetic improvement, specifically genetic variation. As a swine genetics company we rely on genetic variation in order to identify superior animals to retain in the nucleus, send to multiplier units, and boar studs. The superior animals that are selected are more “uniform” genetically compared to the population as a whole; however, variation is present because each individual receives a sample of genes from it’s parents and thus are not identical genetically. In short, uniformity is difficult to achieve through selection, especially for the economically important traits selected for today. Variation can be managed through breed choices, mating strategies, and cross breeding. It may seem obvious but it must be stated that purebred populations are more uniform within breed than across breeds. This is largely because, within breed, the pigs are similar with regards to physical appearance and performance due to similarities within the DNA. When looking across breeds, the DNA will be more variable. When the two pure breeds are bred together their offspring are relatively uniform due to an increase in heterozygosity (Bourdon, 2000), which also contributes to heterosis (http://www.genesus.com/global-tech-report/heterosis). Cross breeding can also add variation if the breeds chosen to produce the crossbred population are not pure. For example, using a pure Duroc boar will result in less variation in offspring when bred to a Landrace-Yorkshire F1 compared to a Duroc boar that contains some Pietrain. On average, the Pietrain may represent 10% of the composition, but individual pigs may contain 5-15%. Therefore, when these Duroc-Pietrain boars are mated to F1’s, there will be variation in the actual composition of the commercial animal, resulting in increased variation of the pigs all the way through market. Our goal at Genesus is to help make our customers profitable and one way we help is through uniformity of our commercial product, which is a Genesus F1 mated to a Genesus Duroc. Our registered purebred populations allow for uniformity through cross breeding to make “true” F1 females and our Duroc does not contain any fractions of any other breed. Uniformity results in easier management and less sorting. Uniformity at the packing plant results in increased profitability to the producer, and that is what counts! References: Bourdon, R.M. 2000. Mating Systems. Understanding Animal Breeding. Second Edition. Upper Saddle River, NJ 07458. Buhr B. Economic Effects Of Variation. National Hog Farmer. April 15, 2008. Patience J.F., K. Engele, A.D. Beaulieu, H.W. Gonyou and R.T. Zijlstra. 2004. Variation: Costs and Consequences. Advances in Pork Production. 15:257.

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