As cattle producers prepare for pasture turnout and breeding season, it is important to evaluate bulls and make sure they are ready to go to work. Along with breeding soundness exams to ensure a bull is fertile and ready for his job, another tool for producers to use is body condition scores (BCS) to make sure the bull is in good condition — not too skinny or too fat.
Phillip Lancaster, Kansas State University beef cattle nutritionist, and Brad White, K-State veterinarian, offer advice on how to assess bull body condition.
According to Lancaster, producers can use the same scoring system for bulls as they do females.
“We use the same system for all classes of cattle, 1 to 9 scale,” Lancaster explains. “That scale is related to body fat composition.”
Bulls should be evaluated like cows: observing the amount of fat the bull is carrying on his back, ribs and hooks and pins.
“As an animal moves from one point on the body condition score to another, they are either gaining or losing body fat and potentially muscle mass,” Lancaster says. “If they start with a lower body condition score and lose weight, that change will lead to a decline in more muscle mass than fat. Conversely, if they are at the other end of the scale, the animal will lose more fat than muscle mass.”
Bulls require more weight change to move between BCS points due to their larger size.
“A rule of thumb,” Lancaster says, “is about 7% of their normal weight at a body condition score of 5 is what they should gain or lose.”
He gave the example of a 2,000-lb. bull that had a weight change of 150 lb. leading to a score change. In contrast, Lancaster says, a cow will shift a body condition score at 100 lb. due to the differences in size and muscle mass.
Monitoring BCS has special implications for yearling bulls who are still growing, White explains.
“Yearling bulls typically have a different body condition than mature bulls at pasture turnout, and the goal is to have the bulls in a positive energy balance heading into breeding season so that they can maintain it through the season,” he says.
Monitoring body condition scores is important year round. White reminds producers the goal should be to keep bulls in a positive energy balance during breeding season, which allows for fat deposition.
White also gave an example that for a cow to improve a body condition score the standard thought is to increase body weight 100 lb. At 2 lb. per day gain, it takes a female 50 days. In comparison, a bull will need longer, so it is important to be proactive.
“Now is the time to make sure the bulls are in the right body condition so that there is time for them to gain weight a head of turnout,” White says.
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