Fall is now officially here, fall calving is in full swing and now is the time to start thinking about your bull power for breeding season coming in less than two months. Too many times in my practice over the past 20 years I have seen cattlemen plan and strategize for handling cows and heifers for the upcoming breeding season, only to forget that their bulls are an equally important part of the breeding equation. I would suggest, rather than a last minute rush, that you start planning now to make sure the bulls are ready to perform.
The first consideration should be, “How many bulls do I need to get my cows and heifers bred?” There have been many recommendations for this number. In a 60-day breeding season, I recommend yearling bulls be expected to cover between 15-20 cows, 2-year-old bulls should cover between 20-30 cows, and bulls 3 years or older should cover between 30-40 cows. I have seen several recommendations that bulls younger than 2 years of age be expected to cover a number of cows equal to the bull’s age in months (i.e., a 14-month-old bull covers 14-15 cows, an 18-month-old bull covers 18-20 cows). These numbers can vary, and the number of females per bull should decrease if synchronization is used in the herd. Herds using shorter breeding seasons than 60 days should consider smaller female to male ratios.
A second consideration is the condition and health of the bulls. Bulls need to have good body condition at the start of the breeding season in order to maintain fertility and conception rates. I recommend that bulls should have a body condition score (BCS) around 6-9. A little heavier is acceptable, but bulls that are too heavy are not as aggressive and have more feet and leg problems. Thin bulls are also a problem, as under conditioned bulls often do not have the stamina to breed cows for an entire breeding season, and fertility often decreases as the breeding season progresses. Plan to feed your bulls well during the breeding season; it takes a lot of energy chasing cows in heat.
Another part of the health equation is to evaluate the mobility of your bulls. Diseased feet and other orthopedic problems involving the legs are one of the top problems I see when evaluating poor breeding performance. Bulls that have impaired mobility do not mount cows normally or get cows pregnant. Important things to look for include swollen or painful feet, grown out feet that need proper trimming and swollen joints.
The third area to evaluate is the reproductive tract of the bull. This traditionally means a semen evaluation performed by your veterinarian. This should be done within 60 days of turnout with cows. Have your bulls tested early enough that if problems are found, there is time to either recheck the bull in question or replace the bull. Occasionally bulls are difficult to collect (they can have bad days, too), so giving a bull 1-2 weeks before rechecking can often result in a normal semen sample. Fertility evaluations should include not only an examination of the sperm produced, but also a visual and manual exam of the penis, the prepuce, testicles and pelvic accessory glands. Observe for signs of lacerations or other injuries that bleed or restrict extension of the penis. Palpate the testicles for symmetry and texture. Is one testicle swollen or extremely soft? Are the testicles easily movable within the scrotum? It is often a good idea to have older bulls, especially those with marginal semen production, palpated to examine the accessory glands for swelling and/or infection.
Dr. Mike Bloss, DVM, owns and operates Countryside Animal Clinic with his wife, Kristen Bloss, DVM. The mixed animal practice is located in Aurora, Mo.