This winter has been difficult for many cow-calf producers. Many ranchers had difficulty harvesting adequate good quality forage because of last summer’s drought and the shorter grazing season.
In addition, we’ve had some fairly cold weather across parts of Western Canada recently, which increases the nutritional requirements of our cows.
I’ve often talked about the importance of body condition in maintaining good reproduction, and most producers and veterinarians are familiar with that message.
However, I came across a recently published research study in the journal Animal Reproduction Science that provides more evidence on the importance of body condition in our beef cows.
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I thought this would be a great study to share because of the dangers of lower body condition scores in many of our herds this year that we may experience because of the drought.
The authors of this study were from Texas A & M University and Sao Paulo State University in Brazil. However, the cows in the study that we will focus on were from two research herds in Oregon.
In total, 893 Angus-cross cows were studied over two years. In each year, researchers used a timed artificial insemination program in the herd followed by a 50-day natural breeding season with a bull-to-cow ratio of 1:25.
At the time of the AI program, they evaluated all of the cows for weight and body condition. The calves were weaned at around seven months old and were weighed at weaning.
The authors conducted a similar parallel study in a commercial cow-calf herd in Brazil with cows of Bos indicus breeding, but we will just focus on the results from the Angus-cross cows in Oregon.
The researchers compared the productivity of the cows with a body condition score of greater than or equal to five with the cows having a body condition score of less than five.
These body condition scores were all done at the time of breeding.
In the United States, they commonly use a nine-point scale for body condition as compared to the five-point scale commonly used in Canada. According to Alberta Agriculture, a five on the nine-point American scale would be equivalent to a three on the five-point Canadian scale. A body condition score of three (or five on the American scale) is often considered as the ideal body condition score.
It’s important to note that the cows that had less than a body condition score of five in this study were not exceptionally thin. On average, their body condition score was just a little over four.
The other cows in the higher body condition group averaged a body condition score of 5.4. The cows that were below the target body condition score were slightly underconditioned, with an average body condition of the equivalent of 2.5 on the Canadian scale.
There were several significant differences between these two groups of cows.
The cows in better body condition obviously weighed more than the cows under the target body condition score but more importantly their reproductive success was significantly better.
The cows that were greater than five had a calving rate of 94 percent compared to 85 percent in the thinner cows.
In addition, 61 percent of the good condition cows were pregnant after the conclusion of the artificial insemination program compared to only 53.5 percent in the thinner body condition group.
When researchers compared the calf performance there were also some important differences. The calves tended to be four days older in the higher body condition group of cows and weighed slightly more than 13 pounds more.
There were no significant differences in calf mortality between the two groups, but the overall weaning rate was 87 percent in the higher body condition group compared to 80 percent in the cows that scored less than five. This difference was mostly driven by the pregnancy rates in the two groups.
The bottom line was that the cows with a body condition score of greater than five at the time of breeding weaned an average of 486 pounds of calf per cow exposed to breeding, compared to 440 lb. of calf per cow exposed to breeding in the lower body condition score group.
At last fall’s calf prices of about $230 per hundredweight, that is a $106.26 difference for each cow exposed to breeding. That translates to slightly more than $10,000 for a 100-cow herd.
Of course, we need to balance this change in productivity with the potentially increased feed costs associated with improving the body condition score of our cows.
This year that may be difficult to demonstrate a huge benefit, but you can see that even a small difference in body condition score resulted in a weaning rate improvement from 80 to 87 percent.
This calculator helps you to look at those expenses and benefits with your own feed costs and shows the value of improving body condition scores.
Ideally it is always less expensive to improve body condition scores in the fall rather than winter, but it’s even more difficult to improve body condition scores after calving has occurred because of the increased demands of lactation. It’s still not too late for many of our later calving herds.
John Campbell is a professor in the department of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.
