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Why all the fuss about body condition of cattle?

Two weeks ago, I wrote about the importance of knowing the crude protein content of your feed or hay for the cows because if it is high enough, then additional protein supplementation might not be necessary until lactation. Adding protein to low-quality forage to increase intake only will increase energy so much. If energy is deficient even though protein needs are met, then body condition scores during pregnancy (or anytime) will decline.

Holding the line in the sand to minimize winter feed costs is important, but be mindful of body condition and its long reaching effects, especially in the last trimester. Net revenue is income minus expenses. Cutting costs too much, i.e. fewer and lighter calves at weaning, is a losing proposition.

The following article written by Warren Rusche, South Dakota State Extension beef specialist, addresses the potential negative effects to the offspring and subsequent cow if she is thin at calving time.

Here is what Warren has to say:

Why is it nearly every article on beef cow nutrition in the winter seems to focus on body condition? Surely with all the advanced knowledge and research through the years, we have something better to go on than a visual estimation of body fat on a cow to evaluate the success or failure of nutritional status?

The short answer to that question is we focus on body condition because it works. The best indicator we have for the nutritional status of a beef cow is her body condition. Right now, most spring calving herds are either in or are approaching the last trimester. Managing body condition in the last three months ahead of calving is important for two big reasons:

Thin cows tend to produce poorer quality colostrum with lower levels of immunoglobulins. They also tend to have calves that take longer to stand and are less able to produce enough body heat to maintain their temperature under cold conditions.

Cows that are thin at calving are less likely to breed back in the first 21 days of the breeding season and are more likely to be open in the fall.

Between those two factors, body condition influences the size of the next two calf checks. That's the reason for the focus, because body condition can have such a sizeable effect on a rancher's bottom line.

There are a number of checklists and visual guides that have been developed to condition score cows. The process doesn't have to be complicated. If you can see more than one or two ribs and the outline of the spine is visible, then the cow is below the optimum body condition score. In a group of cows, the key factor is how many cows in the group are below that optimum line. If there's only a small number (perhaps 5 percent to 10 percent), there is little reason to be concerned. These cows simply might be cattle that don't fit their environment, and spending a lot of extra money on the entire group to pick up the handful at the bottom isn't likely to be profitable. It would be more feasible to sort this group and manage them separately. Larger percentages of thin cows indicate additional inputs will be required or changes to the production system need to be made -- or both.

If additional feed energy needs to be supplied, the sooner that process begins, the easier it will be to put on the necessary weight. To change a cow one body condition score (approximately 70 pounds to 90 pounds of body weight) in 90 days requires approximately 20 percent more energy; 30 percent more energy is required if that change needs to happen in 60 days.

To put it another way, feeding a cow in late gestation an alfalfa-grass mixed hay diet should add approximately one body condition score in 90 days. A 60-day period would require something similar to straight alfalfa as far as energy content. Adding that much weight in 30 days would require a diet similar to corn silage.

* Source: Warren Rusche

Stacy Campbell is Ellis County agricultural agent with Kansas State Research and Extension.