Vet’s Voice: Increasing the cow herd
March 17, 2014
Even though the calendar reports spring will soon begin, we still are waiting for better temperatures. We have not had a lot of snow in our area, but the temperatures have been chilly at best. Recent government reports indicate the nation's cow herd is at thirty year lows. Many articles promote the addition of more females to your herd to increase overall members. This would require you to retain heifers and also possibly gather more pasture. Both of these scenarios require capital outlay. A much simpler way we can increase the number of calves from your herd is to improve reproductive efficiency.
The number of calves born per cow exposed is the measure of reproductive efficiency. This is the primary financial driver of your herd. When a fertile male mates with a fertile female the result is nearly 100 percent the formation of a new embryo. Sadly all of these embryos don't make it to produce a calf. About 30 percent of these embryos are lost in early pregnancy. There are many causes for these losses, some we understand and some we do not, but complexity of reproduction and the loss of imperfect embryos amount for most losses.
As we attempt to shorten the breeding season we may be inadvertently losing cows from our herd which have no reproduction problems. If the embryo is lost in the first 14 days after breeding, the female will generally return to heat again 21 days after her last heat. If we use a bull breeding scenario most cows will cycle in the first 21 days. If they remain pregnant it is no problem, but 30 percent will recycle. In very short breeding window, 40 days, the cows which cycle nearer the end of the first 21 days, may not recycle if the embryo is lost before the bulls are pulled. We suggest you extend your breeding season to about 75-80 days. This gives your cows three chances to become pregnant. If you utilize A.I. all of your first round would be in one day. These animals may only require bulls for 45-50 days.
It is important to stimulate as many females as possible to cycle early in the breeding season. This increases the likelihood of higher pregnancy rates. There are several ways to stimulate cycling:
Once cows begin lactating it is very difficult to add body condition. It is very important to monitor body condition during gestation. Increasing nutrition prior to breeding will help stimulate cycling. Many times this is accomplished by turning the cows to a lush breeding pasture. Time your breeding season to your optimum pasture productivity.
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Disease control :
Consult with your veterinarian and devise a vaccination program which will minimize losses due to infectious diseases which are common in your area. Try to maintain a 'closed herd' to eliminate diseases brought in by strays or herd additions.
Bull breeding soundness:
You must have enough bulls in the pasture to breed the cows coming into heat that day. Mature bulls are usually able to cover cows more efficiently than yearlings. Conduct a thorough breeding soundness exam on every bull in your battery. Also observe each bull breeding an animal to assure he is able to do his job. Always remove bulls which become sick, lame or are not breeding. They may interfere with other bulls in the pasture.
There are many ways to increase your herd's reproductive efficiency. We feel that 90 percent is a fair goal for most of our herds (calves born/cows exposed). Some of the herds in our area with 80 day breeding seasons and mature cows approach 100 percent. Careful attention to detail and consultation with your veterinarian, nutritionalist or extension specialist will help you operate more efficiently. During these times of profitability we can increase our costs of production and still show profit.