The breeding season for many cow/calf producers in Missouri is in full swing or winding down.  Many herd bulls went through fertility checks in preparation for turnout.  However, another key point, after bull turnout, is continual monitoring of the bull battery. Check and recheck your cows and bulls. Ask yourself: "In the last seven days, how many times did I check the cows and how many times did I check the bulls?"  Avoid those disasters of having a large number of open cows at preg check time in the fall.

How many producers really check their bulls? Is the fertility test a quick stop at the local veterinarian on the way to the cow pasture?  A lot can be accomplished by simply assessing the "vim and vigor" of the bull. In many cases, producers give their attention to the cows and the bull is an afterthought.

If calving is complete, cows should be cycling. In fact, a quick check of the cows can be made by remembering that the average estrous cycle of the cow is 21 days. If all the cows are cycling, about 5 percent should be expressing "heat" each day (one day divided by 21 days). I realize, not all the cows calve the first 21 days of the calving season. In fact, typically only 58 percent of the cows calve the first 21 days of the calving season. For typical producers who expose a mature bull to 30 cows, at least one cow should be in heat every day early in the breeding season.

If calf gain is 2.3 pounds per day while nursing, every time a bull misses a cow in heat it will cost the producer over 48 pounds of calf weaning weight.  Most producers do not argue the value of the bull, but the magnitude of that value is often underestimated.

Not only are the genetics of a bull important but his ability to breed is equally critical. Unfortunately, most cattle are bred out on pasture and daily surveillance is not possible. But do stay alert.

As the second-cycle cows (those cows that calved later in the calving season) start to cycle, the typical producer would have 27 percent of the cows calving within the second 21 days of the calving season. If the mature bull is exposed to 30 cows and everything is going right, 17 or 18 cows (58 percent) should have already settled with next year’s calf in the first cycle. That leaves eight or nine cows to breed in the second 21-day period of bull exposure.

Do the math. For the bull that was breeding at least one cow a day during the first 21 days, the same bull during the second 21 days of the breeding season will now only be breeding one cow every other day. In other words, the typical bull should be half as busy during the second half of the breeding season.

Stay alert. If the bull is breeding at a similar or greater rate after being exposed to the cows for three weeks, you may have a problem. Therefore, close observation is a must.

Source: David Hoffman, Livestock Specialist