Select Sires

Genetic Recessives and Reproduction
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired Aug. 29, 2002
With Chuck Sattler,
vice president dairy progeny testing and genetic research,
Select Sires Inc.

Chuck, today we’re talking about some genetic recessives in reproduction, and a complex vertebral malformation is the topic. What exactly is CVM and what does it mean for dairy producers?

It is a lethal condition that is inherited, and it really describes a combination of symptoms, the most notable of which are malformed vertebrae in the fetus or the calf. That’s how it got its name. Consequences of CVM are that pregnancies that have this inherited condition are aborted or result in stillborn calves, and on the farm this translates into reduced reproductive performance for your herd. CVM was identified about two years ago, and since that time A.I companies have implemented programs to control CVM, but because the condition is new, control programs haven’t had much opportunity to reduce the CVM frequency gene yet. About 10 to 15 percent of the cows, we expect, may be carriers of CVM and since CVM is a recessive trait, if a carrier cow is bred to a carrier bull, we expect 25 percent of these resulting pregnancies to be aborted or stillborn. If we put all of these numbers together, it translates to about one in every 200 pregnancies will be affected by CVM.

And Chuck, it seems as though in recent years we’ve been hearing more about genetic recessives, why is that?

Well, with advancing DNA technology, we have improved capabilities of identifying these genetic problems. This is a good news, bad news situation. Certainly these genetic recessives are bad news and I wish they didn’t occur at all. But knowing about them is good because we then have the information we need to avoid them and manage them in our breeding program.

So what can producers do now about this?

Well, the solution is a good ol’ fashioned one. Unfortunately as herds get larger, it becomes harder to record the needed information and to find time to manage all thee details. The solution is to identify the parentage of your cows and then individually mate them to non-carrier bulls or bulls that aren’t closely related. This task can be greatly simplified by using a computerized mating program. A.I. companies, breed associations and others offer a variety of services. Select Sires offers the Select Mating Service or SMS, and what this program does is use the available parentage information for the cows supplied by the herd owner, and then it matches it against the database of information on the bull. So as the computer chooses recommended mating sires for the cows, it looks at each cow’s pedigree to make sure it doesn’t double up on an undesirable recessive trait. It will also avoid mating above a certain amount of inbreeding. With larger herds and increasing amount of genetic information on our bulls, the popularity of these mating programs has greatly increased over the past several years, and it really has become almost impossible to do it without a computer. But it really all starts with proper recording of identification on individual animals and accurate recording of parentage information because that serves as the base of data that is used by these mating programs to control these problems.

Copyright 1996-2002 Select Sires Inc. Last updated 29-Aug-2002.

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