May is just around the corner. Are you ready for spring bull turnout? Many of you are in the middle of calving and some may have just started. Don’t let the hustle and bustle of this calving season derail your next calf crop. The star(s) of your operation are the bulls, which are often ignored and forgotten most of the year. However, it is critical to have a plan prior to turnout as too how much bull power you will need versus how much you have. Simple questions to start the decision making process are: How many cows will need bred? How many groups are those cows divided into? How many heifers, and do you have a bull designated for your heifers? Are you going to synchronize the herd or heifers? Do you have a backup plan if your bull fails the Breeding Soundness Evaluation? What condition are your bulls in?
A healthy mature proven bull should be able to cover between 40-50 cows in a breeding season given enough time. What if you are condensing your breeding season to the recommended 60 days to tighten up your calf crop? Can your bull accomplish his task? It is often necessary to increase your bull numbers to maximize servicing multiple cows in estrus during the same day. A healthy immature or unproven bull should only be expected to cover half the number of cows (20 or so). Synchronizing the herd also adds the dilemma that multiple cows will come into estrus together (the whole point), but any cow not bred due to low bull workforce will have to wait until the next cycle approximately 21 days later. There are only three cycles within a 60-day breeding season, possibly four, if you synchronize and turn bulls in at the first cycle. Maximize potentials by thinking ahead.
A great place to start is the Breeding Soundness Evaluation (BSE). Yes, the highlight of this examination is evaluating the bull’s semen. However, there is more to it than, “how many swimmers are there?” The basics should be looked at by everyone, including you, the producer. Is the bull lame? Even mildly lame? Has he been lame in the last few months and “recovered?” What was the cause of the lameness? Was it hip, knee, shoulder or foot? Was it a front leg or hind limb lameness? A lame bull won’t or can’t breed for two simple reasons. It either hurts too bad to mount a cow, or he just can’t keep up with the herd identifying cows in heat. Hip, knee or shoulder injuries take a long time to heal if they ever do. Heel warts and abscesses need proper attention before they can recover but again it will take several weeks for complete resolution of the problem. A lame bull at turnout will not sew the calf crop you seek.
What is the body condition score of your bull? A hardworking chap can drop two to three condition scores over the season. On a 1,500-pound bull this can add up to 500 pounds in extreme situations. Poor condition on your bull at the start of the season may lead to illness, injury or just more time wanting to eat instead of breed. It may take months for this bull to recover. Now, on the opposite end of the spectrum over conditioning is also a problem. Overweight bulls are often lazy, have more lameness issues and quit working when it gets hot before properly conditioned bulls will give up. Let’s also not forget these guys need annual vaccinations for respiratory and reproductive diseases at a minimum. Pinkeye vaccinations are recommended as well. Bull’s need all their senses to perform exceptionally. Deworming and mineral injections should be considered too. If you don’t intend on large inputs into the herd this year, at least apply it to the bull(s).
Let’s get back to the BSE. This is my opportunity as a veterinarian to put my hands on the animal. Palpation of the testicles and epididymis are important especially if the bull fails the BSE. It is also important to visualize if the bull can maintain a straight erection and protrude the penis from the sheath. After all, the most fertile semen in the world has to be placed in the correct spot to conceive. On young bulls this allows us to see if there might be a persistent frenulum present. A frenulum is a band of connective tissue that deviates the glans penis abnormally. This is correctable with minor surgery but if not found before breeding season could be very detrimental. Regardless of age we look for Herpes virus infections, and/or papillomas. Correction of this is removal of the papillomas and sexual rest. Yes, sorry but that bull just got scratched from the lineup for a while. Continuing the examination, is the semen viable? Does the bull produce adequate volume of semen? Does the bull’s semen exhibit adequate motility? Are there any primary or secondary defects present with the semen? These are all questions, which take a mere few minutes to determine. The wrong answers to these questions might take a little longer to figure out, but that’s the point for doing all of this.
Knowledge, it is impossible to optimize your plans for the future without utilizing information available today. Let’s say your bull(s) fail their BSE. If the bull is given the unsatisfactory breeder or deferred status, it will be recommended to re-test in 60 days. Why 60 days? This is the length required for the process of spermatogenesis, from progenitor cells to functional spermatozoa within the testicles. Whatever has caused the bull’s semen to die or become denatured (i.e. fever, gland infection, etc.), it could potentially take this long before we see viable semen present in the ejaculate once again.
Finally, every BSE should be concluded with testing for Trichomoniasis. Tritrichomonas Foetus is a protozoal parasite that is spread to the reproductive tract of the bulls and cows during coitus from an infected individual. Coitus must occur for transmission but an infected bull can spread this disease to every cow he breeds. Cows can clear the infection with sexual rest but the loss of a calf crop is devastating. Trich causes death to fetuses during the first trimester of pregnancy often causing a uterine infection that keeps the cow from returning to estrus. Bulls once infected will never clear the infection and must be sold for slaughter only. It is required by Missouri law to have a bull tested if being sold, the only exception the seller being willing to sign an affidavit stating a young bull is a virgin. Virgin meaning has never bred, not even heifers. If you have owned the bull for several years, the thought of skipping this test might arise. Just ask yourself; can you guarantee without a doubt that your bull hasn’t crossed the fence or the neighbor’s bull hasn’t either, has there been any fence down allowing animals to mix? Placing your calf crop at risk is simply not worth it especially since testing is economical and easy.
Remember, a BSE is a one-time look at the bull allowing us to infer the recent past but never the future. Veterinarians can’t tell you if the battle will be won but we can keep you from running in with a bent sword and wet powder. May is coming, are you ready?


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