Body condition scores can be used to assist in reproductive management

Utilizing body condition scoring as a management tool can help ranchers improve weaning weights, conception rates and overall calf health, according to Naomi Paley, Saskatchewan Ministry of Agriculture regional livestock specialist.

The body condition score (BCS) is accessed on a scale of one to five, measuring body fat on a cow. The score can be determined by feeling cows in low-muscle areas of the body such as the short rib to determine the fat content, Paley explains. 

“Body condition can effect a lot of things in cattle,” says Paley. “From calf health to rebreeding and subsequent weaning weights, producers can save money by understanding how to manage body condition scores.”

Calf health

“When a cow loses condition, a lot of things happen,” says Paley. “When she loses weight, she will produce less milk and lower quality colostrum, which effects both the calf’s weight and initial immunity.”

“Calves born to cows with a body condition of two or less at calving or to cows that lose condition after calving can have anywhere from five to 25 percent reduction in weaning weights,” Paley says. “This is largely due to reduced quantity and nutritional value of cow’s milk.”

Rebreeding

Paley conducted an experiment using 100 cows divided into thin, moderate and good condition at the time of calving. Only 66 percent of the cows ranked thin were in heat at 90 days post calving, in comparison to 91 percent and 100 percent of cows in the moderate and good categories, respectively.  

“Our goal shouldn’t be to simply get cows bred. Our goal should be to get them bred as soon as possible,” says Paley.

“For every cycle the cow remains open, her calf will be 20 days younger and 40 pounds lighter on average,” says Paley. “If we assume a calf is growing an average two pounds per day, that is $2.25 per pound and a total of $90 per head lost for every missed cycle.”

As a more large-scale example, Paley estimates a rancher with 100 head will lose $5,000 in revenue in the fall if only half his herd is bred on the first cycle. At the estimate of 40 pounds per calf and $2.50 per pound, this 2,000 pounds of lost weight totals to $5,000 in revenue.

Improving scores 

“It takes 200 pounds of fat for an average cow to gain one full condition score,” says Paley. “That equates to 25 bushels of barley and approximately $81.75 per head or 2,000 pounds of hay and $100 per head.”

Paley explains it is simply more expensive and difficult to put weight on a cow during the winter than to just maintain good condition year around. 

“The feed and biological costs are much higher,” says Paley.

Understanding energy requirements

Karin Schmid, a beef production specialist with Alberta Beef Producers, explains energy requirements change as the cow progresses through pregnancy and calving. 

“Assuming calving happens in March, January is the last chance to add condition to a cow before her energy needs increase and condition becomes very expensive to add,” says Schmid. “Energy requirements are highest in late gestation and lactation.”

“We also have to pay special attention to first calf heifers,” says Schmid. “These heifers are still growing and need to be managed differently than the cows in a herd.”

“In comparison to mature cows averaging 1,300 pounds, a heifer weighs 900 pounds,” says Schmid. “Heifers need 18 pounds of total dry matter per day in the third trimester as opposed to 15 pounds for mature heifers and an additional third of a pound of crude protein per day.”

“When we’re talking about under-conditioned cows, we want to add condition when energy requirements are the lowest, which is typically around weaning time. This acts as an insurance policy as we go into the winter and energy requirements increase,” Schmid says.

Management groups

“We want to divide the herd into three groups – mature cows, replacement heifers and second-calf cows and older, thin cows,” says Schmid. “Cows at different stages of production have different needs.”

“Mature cows will be just fine on average-quality forage and extended grazing systems,” says Schmid. “Heifers need good-quality forage and maybe some supplementation depending on their rate of growth and the intensity of the winter.”

She adds, “The third group will definitely need good quality forage and supplements to get through the winter in good condition.”

Callie Hanson is assistant editor of the Wyoming Livestock Roundup. Send comments on this article to roundup@wylr.net.