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North American
   Limousin Foundation
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NALF Line
November 2009

 
Cow Weights, Condition Scores Help Manage Costs
By Lauren Hyde, Ph.D., director of performance programs
 

It is no secret that low-cost, efficient producers are the survivors in the cow-calf business. As production costs continue to rise, cow-calf producers who manage their costs most effectively will be those who stay in business for the long run.

One of the keys to cost control is matching the genetic composition of the cow herd to the environment and available feed resources. Feed costs account for about 65 percent to 80 percent of the total costs of production, and an animal uses the major proportion of feed (about 70 percent to 75 percent) for maintenance.

The maintenance-energy (ME) requirement is the amount of daily dietary intake that will cause an animal neither to gain nor to lose body energy. Bigger cows have a higher ME requirement than smaller cows do because of their larger body masses. Likewise, cows with higher-than-average milk production have greater energy needs than cows with lower milk production do.

Two breed associations have developed selection tools to allow producers to identify genetic differences in cow ME. Both predict differences in the ME requirements of individuals’ mature daughters, but they are expressed in different units. The American Angus Association’s cow energy value ($EN) is expressed in dollars saved per cow per year, and the Red Angus Association of America’s ME expected progeny difference (EPD) is expressed in megacalories (Mcal) of energy required per month for maintenance.

The ME EPD essentially is an index of two components: (1) mature-cow body weight at weaning adjusted for body condition score (BCS) and (2) the animal’s milk EPD. Sires that produce daughters with higher milk production or larger mature sizes will have higher (less favorable) ME EPDs because their daughters will require more dietary energy for maintenance.

Collecting the data used to compute ME EPDs is not complicated. In fact, many of you have been collecting it for years. Only three observations are required: (1) a calf weaning weight, (2) a cow weight and (3) a cow BCS. A cow weight does not count without a valid BCS and calf weaning weight.

You should collect mature-cow data at weaning to ensure cows are in the same stage of production. Weaning also is a practical time because cows and calves usually are in close proximity to each other. Because it might be difficult to process cows and calves on the same day, you may take cow measurements within 30 days of weaning.

Capturing mature-cow weights and BCSs will help you monitor your cow herd, allowing you to minimize costs and improve profitability. As the North American Limousin Foundation’s (NALF’s) mature-cow database continues to grow, we will be able to compute ME EPDs of our own and give users of Limousin genetics the means to match their cow herds to their production environments and feed resources.