The Non-Cyclic Cow
Script of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired June 15, 2006
With Ray Nebel,
Senior Reproduction and Herd Management Specialist, Select Sires Inc.

Ray, today we are talking about the non-cyclic Cow where estrus is not observed, and Ray, you have two possible causes for this.

Yes, Bill, you know a lot of times we are looking for a silver-bullet, but our heat detection and the accuracy of our heat detection is important for going ahead and putting semen into cows to produce pregnancies. Many times we also talk about the anestrous cows, cows that don’t cycle. Many years ago there was a term called “silent heat,” I didn’t care for that term because at that time, 20 years ago, I felt that it was missed heats and not cows not showing heat. Today it is a little bit different in that we have high-producing cows that go into negative energy balance, and it is probably a term that really ought to get back in vogue as far as the “silent heat” or the cow that shows anestrous.

What are the possible causes for anestrous?

The possible causes of anestrous, of course, the one we just mentioned is the failure to properly observe cows in estrus, and that is really a management issue of “are we taking the time to be out there observing cows and looking for late cows?”. Some of that comes down to adequate records of knowing who has the best chance of expressing estrus, cows that were bred 18 to 24 days ago of course have the best chance. The location of cows are at during estrus detection and then when we have a group of cows that we get most of them pregnant, the last few cows are much harder to get pregnant. The anatomical feature that really limits the expression of estrus is feet-and-leg, or lameness, problems. As a cow gets lame, has foot problems, she expresses estrus to a much lower degree and it is much harder to catch her in heat. Along with that is slippery flooring with slick concrete, or where we don’t have rubber belting, the cows don’t have sure footing, and she’s not going to express estrus because she’s not sure she can stand the pressure that is going to go on from mounting activities.

True anestrous, though, is probably due to energy deficiencies, cows losing large amounts of flesh due to high milk production and under feeding, or poor dry matter intake. Anemia could be a problem, often inaccurate protein or iron, selenium and vitamin E, there could be some phosphorous deficiencies, but this is very rare; if it does occur it is usually going to be in heifers. Piometria, a cow that is infected many times, before long the system thinks she is really pregnant because of the extended uterus, so we need a vet check and we find out that we need to dump the uterus and get the contents out. One that we see every now and then as we think the cow is not showing heat, what happens is that she is pregnant. In pregnancies she will hopefully express anestrous for nine months.

Another one that has become more and more common is the cystic cow. We used to think of cystic cows as cows that would show heat every two to three days and now we see a luteul cyst more often where cows go anestrous and don’t express estrus. There are a number of different things we could look at as far as true anestrous, but we really need to look at both sides of that coin: Is it a management factor that we are not catching the cows in heat, or is it a cow factor where the cow is not expressing heat?

That is Ray Nebel,senior reproduction and herd management specialist at Select Sires Inc.