It is breeding season once again and we often get the question, “will heat synchronization work in heifers?” Heat synchronization will work, but before we say yes, I like to look at each individual case and see if the producer has the time and facilities to do so. Some producers want to do large numbers, other may only have a few cows, and so each case must be assessed differently.
You need to consider are the heifers mature enough to be cycling or has the owner noticed the biggest percentage of heifers showing heats? I think heifers need to weigh 80 percent of their expected mature body weight and the animal needs to be in good body condition for the animal to cycle, if they are not, I think it is a waste of time and money. The animals need to have been in heat or seen cycling in order to get the best results of the heat synchronization plan. Some producers plan on heat synchronization to obtain the best performance from a large group of calves, so if the producer is planning on a large number of heifers being bred all at the same time, usually in a 36 to 72 hour window, there needs to be plenty of bull power. If the producer plans on artificial insemination, I consider the number of animals and semen expense before I make a plan. If the producer plans on breeding a large number at one time then time-breeding is most likely the thing to do as far as stress and labor. If a producer is doing small numbers and semen cost is a factor, I would suggest breeding 12 hours after standing heat and facilities need to be adequate for the plan. The animals need to be caught in a way that has little stress, if this is not possible, AI may not be beneficial and the producer may need to consider natural breeding.
It would be beneficial to do a reproductive exam on the heifers. This will eliminate most heifers that will not be able to breed, a free martin or animal with a reproductive anomaly where they can not conceive. It will also give the producer an idea of the number of animals that are cycling. Remember if they aren’t cycling, the medication will not work.
The next way to increase the conception rate is good nutrition and vitamin and mineral supplementation. Remember again if the animals are thin and in poor body condition, a producer will not get the best results from a heat synchronization plan. Another factor is internal, as well as external parasites whether it is stress from flies, anemia from blood sucking lice or intestinal parasites. The parasite load will take away from the animals overall health and this will not be good for conception rates.
Heat synchronization can be done but a producer must evaluate the whole picture before he or she decides to invest the time and money. If a producer decides the benefits will be to their advantage, then I would figure out which heat synchronization plan will be best for that producer’s needs. Talk to your local vet to decide which plans will work best for you. There are many ways to go about heat synchronization and all have advantages and disadvantages.
Dr. Rusty Waide, DVM, has been the owner of Buffalo Veterinary Clinic in for 21 years.