When spring-calving season is over or almost complete, then the next breeding season is already beginning or just around the corner. During a 75-90 day breeding season, it's not uncommon for a bull to lose 100 to 200 pounds - sometimes even more. For that reason, your bulls should be in a body condition score (BCS) of 5.5 to 6.5 and consuming primarily a high roughage diet (hay or pasture). If your bulls fit this description going into the breeding season, congratulations! You are ahead of the game. You understand the benefit of evaluating bulls well before the breeding season so that any needed adjustments in diet and condition can be made gradually.
Often, many of us aren't so on top of things and don't give the bulls much attention until their annual breeding soundness examination 30-60 days before turn-out. That's not much time to make adjustments in body condition. For instance, consider a bull that is in a BCS 5 and weighs 1,600 pounds. You need him in a BCS 6 at turn-out, so he'll need to gain about 125 pounds. If you have 60 days before the breeding season, he'll have to gain over 2 pounds per day. It's possible to get that rate of gain and still use a primarily roughage diet. If you only have 30 days, though, he'd need to gain over 4 pounds per day. That rate of gain is possible, but his diet would have to be mostly concentrate, with very little roughage.
If you let conditioning slip up on you, your options are limited, but all may not be lost. There are some things you can do. First, use what time you have left before turn-out to gain the bulls at a moderate rate of 2-2.5 pounds. Supplementation, if any, will depend on pasture or hay quality.
Second, rotate the thinnest, most active bulls out of service periodically. Rest them and supplement with a high-energy feedstuff. "Periodically" may mean as often as weekly, if necessary. Third, consider increasing your bull power by adding another one or two to the battery.
Fourth, observe the bulls frequently during the breeding season, especially in situations where the bulls lack adequate condition starting out. Record the service dates of the cows, then observe those females in 18-23 days to make sure they are not coming back into heat. If they are, it's almost certainly the bull's fault.
Fifth, vow to evaluate the bulls next year at least 60-90 days before the breeding season. This lead time will allow you to properly "fit" the bulls for the breeding season. Remember the three most important factors:
- Body condition score: Provide a level of nutrition so bulls reach a BCS of 5.5 to 6.5 at the start of the breeding season.
- Diet: Allow adequate weight gain to attain desired BCS using a maximum of forage (hay or grass) and a minimum of concentrate.
- Exercise: Provide plenty of space so bulls can become accustomed to covering lots of ground.