When a cow comes up open in a pregnancy check, we often assume it’s because of some fault with the cow. Maybe she was too thin or not cycling well at breeding time. But maybe it’s not the cow at all. According to Karla Wilke, University of Nebraska-Lincoln Range Management and Cow/Calf Specialist, it could be an issue with the bull’s body condition.
Photo by Troy Walz
According to Wilke, bulls in a body condition of 5 or 6 have better semen quality than those in a 4 or 7. In addition, they can lose 100 to 200 pounds during breeding season. That’s the equivalent of one to two body condition scores. That means that if your bull isn’t in a BCS of 5.5 to 6.5 now, you have about 90 days to improve his body condition to something that will serve you well during the breeding season.
Is Good Grass Enough?
Spring is typically a time when bulls are fed hay when green grass is not available, a ration that can help them maintain weight, but not gain. Here are some feeding examples for different quality hay and different supplements to help a 1300 pound bull gain 100 pounds.
| Time Frame | Hay Quantity/Quality | Supplement |
| 90 Days | 35 Pounds meadow hay (56% TDN 10% CP) |
1 pound Distillers Grain Based Cube |
| 60 Days | 31 Pounds meadow hay | 3.5 pounds Distillers Grain Based Cube |
| 90 days | 29.5 pounds millet hay (54% TDN, 8% CP) |
14 pound of corn silage (68% TDN 8% CP) |
| 60 days | 23 pounds millet hay | 27 pounds of corn silage, 4 pounds of wet distillers grains (108% TDN, 30% CP) |
While you may not be feeding this kind of hay, or these particular supplements, this can give you and idea of the quantity and quality of feed you’d need for weight gain. Since mature bulls often weigh more than 1300 pounds, remember to adjust feed quantities accordingly.
Evaluate Bull Body Condition Early
Sixty days is the minimum amount of time for improving bull body condition, so it’s a good idea to check your animals now. This helpful booklet from the University of Nebraska-Lincoln Extension has everything you need to know about body condition scoring for beef cows.
