Factors That Affect Fertility: Repeat Breeders
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio Which Aired June 8, 2006
With Ray Nebel,
Senior Reproduction and Herd Management Specialist, Select Sires Inc.

Ray, this week you are talking about factors that affect fertility.

Yes, Bill. I thought first we’d talk about repeat breeders. The common question that comes up is “what do you do with repeat breeder cows?” There are probably almost a dozen different possible causes of repeat breeders. Some of the easy ones to look at and eliminate as probable causes are improper timing of insemination, and what I mean here is breeding too early or too late; second would be frequently insemination cows based on secondary signs of heat. Now I know many are now using synchronization programs for first service, but we are still relying heavily on the test for estrus for second-repeat services. So, are we breeding cows on standing heats or on secondary kinds of heats?

The next would be high incidence of uterine infections. This goes back to the transition cow and how clean we are at calving, our facilities, and overcrowding. These would be some of the common causes of uterine infection. Improper insemination techniques that are used, semen damaged during storage and handling, and of course this would definitely cause repeat breeders because we are not putting optimum number of sperm into the cow to allow for fertilization.

The last few that we will talk about are out there where we are looking at more of an extraneous cause such as embryonic or fetal mortality. Improper palpation techniques are probably one that doesn’t occur very often, but the producer always has that in the back of his mind. Heat stress—we are coming up to summer and we always see an increase in fetal mortality in the summertime because of heat stress; so we need to have heat abatement as well as we can afford to have it going into this time period.

Deficiencies in crude protein or excessive degradable protein will cause increased fetal mortality; also gross over-conditioning. A lot of times we think of a thin cow, but cows that we had trouble getting bred last lactation usually stayed in milk a long time, over conditioned and calved back too heavy. If we do get that cow pregnant, many times she loses the fetus.

So, to sum it up, what is your best advice in trouble shooting repeat breeder cows?

The kind of question that comes up most times is “I’ve got this group of cows that I seem to be breeding over and over again.” When you really need to take a logical approach, is this something that is management that is causing it through our breeding techniques or timing of inseminations, or is it something extraneous that could be causing it, such as diseases, some toxicities or imbalances. There are a number of different causes, and the logical approach is to start to eliminate these causes to narrow down a field so we can pinpoint when we are doing trouble shooting for a repeat breeder cow.

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