Four tons of calf is not easy to give up
The fall of the year is the time to make herd evaluations and managerial and nutritional improvements without fighting the weather. The key to understanding the overall performance of a herd is reproduction.
For example, the calving distribution of the herd is very important because delayed calving costs pounds. The calving distribution indicates how many cows calved within each 21-day period of the calving season.
The actual number of pounds lost due to later calving is critical. By viewing the average calf weight by 21-day calving periods, this lost income potential actually can be traced.
For example, let’s compare two herds of cattle that calved in 2008 and restrict our discussion only to those cows that calved during the first, second or third 21-day period of the calving season. The first herd (herd A) has 186 calves during this 63-day period with 74.7 percent of the cows calving in the first 21 days. In other words, the cows bred well. The larger second herd (herd B) has 256 calves during this 63-day period, but only 42.5 percent of the cows calved during the first 21 days.
Is there a difference in these two herds? Obviously herd A is a tighter, more reproductively responsive herd. So what does this mean? One could evaluate actual weaning weight. However, even before overall improvement in calf weaning weight is discussed, a more serious problem is the pounds of weaning weight given up due to later calving.
In herd A, the more reproductively responsive herd, those calves born during the second 21 days of the calving season are 42 pounds lighter than those born during the first 21 days of the calving cycle. Those born during the third 21 days of the calving season are 86 pounds lighter than those born during the first 21 days.
In herd B, the herd with a more spread-out calving season, those calves born during the second 21 days are 41 pounds lighter than those born during the first 21 days. Those born during the third 21 days of the calving cycle are 88 pounds lighter than those born during the first 21 days.
I realize that not all the calves can be born during the first 21 days of the cycle. However, the degree of effort put forth to keep cows calving early in your chosen calving season needs to be proportional to the amount of weight lost in the lighter calves. Regardless of herd A or B, both herds are giving up more than 40 pounds for every calf delayed into the second cycle and almost 90 pounds into the third cycle.
Adding this weight loss to the number of calves in each cycle, herd A gave up 1,680 pounds on 40 calves born during the second 21 days of the calving season, while herd B gave up a whooping 4,551 pounds on the 111 calves born during the second 21 days.
If one looks at calves born during the third 21 days of the calving season, herd A gave up 602 pounds on seven calves and herd B gave up an additional 3,168 pounds on 36 calves. Adding up the weight loss, herd A lost 2,282 pounds or 1,231 pounds per hundred calves, while herd B lost 7,719 pounds of calf or 3,045 pounds per hundred cows. Granted, the younger, lighter calves may bring more dollars per pound to help offset some of the losses, but they don’t bring more dollars per head.
However, the overriding principle is one of pressure in a herd to keep the cows calving early with respect to the desired calving season. Each producer sets his or her calving date for the type of cows he or she wants to raise and then needs to review the herd’s reproductive performance utilizing the calving distribution.
If you’re not satisfied, evaluate the cows, check the condition score, and take steps to start improving the most likely problem, which is cow nutrition. Doing it next spring after calving is too late. See your nutritionist, because 4 tons of calf is not easy to give up. — Kris Ringwall
(Kris Ringwall is a North Dakota State University Extension Beef Specialist, Director of the NDSU Dickinson Research Center and Executive Director of the North Dakota Beef Cattle Improvement Association. He can be contacted at 701/483-2045.)