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Having a successful breeding season

Many little things go into a successful breeding season. One measure of success is the first cycle conception rate. It is the number of cows that conceive or settle during the first cycle. The average is 50 per cent. It doesn’t seem to matter whether it is natural service or AI or synchronized or timed breeding or not. That seems unacceptably low to me.

I hear of some producers getting 70 or even 80 per cent of their calves within the first 21 days of the calving season. (That is the easiest way to measure the first cycle conception rate.) How do they do it? The first point to make is that fertility is an inherited trait. You can select for it or select against it. That is the major reason that we pregnancy check: to find out who is pregnant and who we have to get rid of. Keeping them and catering to their special needs can work to select for more sub-fertile females. Fertility is the number one economic trait.

Bull testing is another way to eliminate sub-fertile animals. Good serving capacity and a strong libido in a bull can be passed on to his daughters.

Heifers should be the most fertile animals in the herd. If they do not catch on the first or second breeding at the most, you have to wonder: why are you keeping them? If they are hard to settle as heifers with no stress on them, they are going to be even harder to settle while raising a calf. Sophomore slump is a documented condition. First calvers haven’t had enough energy to become second calvers. The buyers call them “heiferettes” and they are very common in the fall after preg-checking.

One way to cheat yourself is to leave the bulls in longer. I remember a progressive son who finally convinced his father to pull the bulls after a 60-day breeding season. At preg-checking time he had some very poor looking animals that were open. The dad said, “See, I told you that we should have left the bulls in longer!” He just didn’t get it.

Energy increases fertility. A dry, pregnant beef cow requires approximately 10 megacalories (Mcal) per day to maintain her. A lactating cow will require almost double that, 16 Mcal per day. Feed samples can give you these numbers. The astute cattleman can tell if the cows are getting enough energy simply by looking at their condition. The better the body condition, the higher the conception rate.

However, fat cows are hard to calve out. This is a mistake that I run into frequently. We overfeed our pregnant cows and underfeed our breeding ones. The peak energy requirements occur during lactation, not pregnancy. Keep your calving cows in reasonable condition, about halfway between too fat and too thin. This helps them to calve easily and gives you some room to flush them.

Heifers are especially susceptible to this mistake. If you start flushing too early in a high milking herd you also run the risk of causing scours. Wait until those calves are two to three weeks old. Then feed those girls as much as they can eat of the best feed that you have. After all, that is exactly what they would be doing on pasture in June and July, during nature’s breeding season.

Natural seasons automatically change a cow’s body condition: thin in spring, fat in the fall. Apply this to your herd management. You can save feed costs and improve your fertility. Researchers have demonstrated that it works.

A vaccination program is also important. IBR, BVD (two types), Neospora and Hemophilus somnus are reproductive diseases. They can cause infertility, abortions and weak calves. Vaccinate all animals with MLV, before the breeding season. MLV vaccines are recommended at least 2 times between weaning and breeding for the best chance of protection.

Persistently infected carriers of BVD or neospora are the Typhoid Marys of the cow world. They can create a bio-burden of infectious agents that even the best vaccination program cannot protect against. Buying or marketing replacement animals free of these horrible afflictions is highly recommended. Blood tests are available. Vaccination and a herd free of carriers is the best way to protect against fetal infection and spread within the herd.

Vibrio (campylobacter) and trichomoniasis are venereal diseases. They are contracted by poor management practices. There are vaccines available, if they are a risk to you.

Stress management (of the cattle) before, during and after the breeding season can make a huge difference. Corticosteroids and adrenalin impair fertility. Shipping and handling are very hard on cattle fertility. If you ship just before breeding it can take a complete cycle before the cows will settle. Shipping before implantation of the embryo is also risky.

Handling during breeding is a real knack. Some AI technicians have a dark box to keep the cattle calm during AI. Too many times through the chute, rough or not, will have a negative effect. Keep your synchronization program simple.


  1. Start with fertile animals, both cows and bulls.
  2. Manage their body condition with energy.
  3. Vaccinate.
  4. Manage stress.

Some year I hope to be able to crow about 70 per cent of my calves coming in the first three weeks. It is hard to do and if you have done it, you have earned your bragging rights.

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