It Takes Two To Produce A Calf

   Many producers have been calving since early February. Probably the furthest thought in their mind is the herd bull.
   However, the herd bull is often nutritionally forgotten or most marginalized component of the beef cattle enterprise. This is never advisable because proper bull management, particularly nutrition, is vital to ensure the long-term viability of the beef cattle enterprise.
   Herd bulls contribute one-half of the genetics to each calf crop. Without a functional bull his contribution may be hampered and an adequate calf crop is not realized. Therefore, proper nutritional management of herd bulls as well an annual breeding soundness evaluation (BSE) is paramount to a successful breeding season and economic viability of the beef enterprise.
   The conditioning period prior to the breeding season is very important for both growing and mature bulls. Sale of growing bulls has been robust in the Midwest, but remember these bulls generally have gone through the development phase which consisted of high-energy concentrate based diet. These bulls will need to be transitioned from a test or development diet to a conditioning or maintenance diet that is often forage based. Keep in mind that these bulls will be stressed during the diet transition period.
   The transition/conditioning period should be around 60 days. This time frame should allow a sufficient amount of time for the bulls to adjust to the new diet. Well conditioned bulls during this time period will reduce their fat cover and “harden up”. This will also provide thin bulls with an opportunity to increase their body condition.
   At the end of the transitioning period, the herd bull should enter the breeding season with a body condition score of 5.5 to 6.5 (on a 9 point scale). This body condition score will provide the bull adequate body reserves to utilize during the breeding season since nutritional attention to bulls during the breeding season is nearly impossible.
   Bulls can easily lose 100-400 lbs of body weight – equivalent to loss of 1 to 4 units of body condition. The amount of bodyweight and body condition loss will be influenced by the age of the bull, prior body condition, length of the breeding season, level of activity experienced by the bull, and breed type of the bull. I
   t is advisable to conduct a BSE of your herd bulls before the breeding season. Very few bulls are “sterile” and unable to produce any offspring. But, 10 percent to 25 percent of bulls have reduced fertility or possess physical problems which reduce their ability to sire calves. The breeding soundness evaluation is a useful tool in identifying these bulls. Eliminating bulls with physical problems or reduced fertility from the breeding herd will improve overall reproductive efficiency of the herd.
   Producers need to recognize that a BSE does not evaluate a bull’s breeding drive or ability. The producer should ensure that bulls, especially new ones, are observed during the breeding process and that they are interested and able to mount and inseminate females.
   Remember that approximately 75 days are required for the bull to produce semen. Sperm production requires about 60 days and an additional 15 days are required for transport through the system, during which further sperm maturation occurs. If the BSE is conducted 60 days before the start of the breeding season, then you have an opportunity to retest the bull or find a replacement bull.
   During the calving season begin to assess your herd or newly purchased bull. Provide the bull with an appropriate transition/conditioning period and conduct a BSE and assess the bull’s breeding drive or ability. By assessing the bull’s breeding potential early, you will have ample opportunity find a replacement, if necessary. Δ
   DR. TERESA L. STECKLER: Extension Specialist, Animal Systems/Beef, Dixon Springs Agricultural Center, University of Illinois

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