Is it Time to Look at Changes in Swine Genetics?

Temple Grandin

(Updated November 2000)

Assistant Professor of Animal Science
Colorado State University

As the swine industry has become more integrated, the case of extreme genetics where pigs have been selected for maximum lean and minimum fat has been reduced. Pigs selected for the largest muscles will have more PSE and large tough muscle fibers. I have been observing fewer pigs at the slaughter plants that have excitable genetics. Excitable pigs often have poorer pork quality. The elimination of the stress gene in some herds has produced calmer pigs which are easier to handle and that have better quality pork. Marketing systems that reward producers for quality instead of quantity will motivate producers to stop breeding pigs for the largest muscles. We need to look at moderation in genetics in breeding sows. Yes, we've got to have high-producing animals. But we don't need to have animals with lameness problems because they're too large for their own bone structure or they're hard to handle and transport because they are so excitable.

From a welfare standpoint the biggest problems with sows right now are 65%-70% appetite drive and 25% movement restriction. That's what the research is telling us. Studies have been able to quantify that feeding motivation. Some sows will push a switch upwards of 95 times just to get an additional halfcup of grain. Movement restriction problems come into play when she's put in the crate but the motivation for more food is even greater. She'll bite the bars and other such behavior in an effort to satisfy that hunger.

Pigs are being bred to eat. That's fine for market pigs and early growth development gilts. They're allowed to eat all they want. But sows don't have that luxury.

I'm not saying the genetic improvements that have been made to this point need to be scrapped. What I'm saying is we need to look where we're going from here. The sows we have now can be satisfied by adding roughages to the diet. But if we keep going down the same genetic road that we're on, we're going to have sows that are so driven by the need to eat that they will be continuously frustrated and hungry.

The first step is getting rid of the stress gene. Fortunately some integrated systems have already done this. Then there needs to be something done with the behavior of sows. That is being done on a small scale. There are sows with new genetics that seldom fight. They are being raised in group housing and they don't fight or bite each other. It's being done. Now hog producers have to decide which road they want to follow -- continuing to put pounds on at all costs or moderating that to raise animals which are easier to handle and which will also have better pork quality.

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