Timothy Page | 5/15/2018 8:43:03 PM
Breeding Soundness Exams (BSEs) for bulls should be an essential part of a beef producer’s overall management plan and can be a key to fertility and high conception rates, high calving rates and the most important high weaning rates. Progressive beef cattle producers focus a lot of attention on managing their cows and heifers to improve fertility and conception rates. Although management of the cows and heifers is essential, concentrating management entirely on the females and not worrying about the bulls can be a disaster. The importance of the bull in the breeding program is often underestimated. Producers searching for a cost-efficient method to promote a successful breeding program should find BSEs for bulls extremely beneficial. The cow is responsible for some of the genetic makeup of one calf per year, while the bull is responsible for half of the genetic makeup of 25-35 calves per year. The bull’s ability to detect cows in heat and breed them is clearly vital to a successful breeding program. One tool producers should all use to assure success is the BSE. Examining bulls for breeding soundness before the breeding season will detect most bulls with fertility problems. For the exam to be successful, a veterinarian should evaluate the bulls 30-60 days prior to the start of the breeding season. That gives producers enough time to replace any questionable bulls.
The BSE consists of three main parts. They are the physical examination of overall performance, internal and external examination of the reproductive tract and an evaluation of semen for normality and motility, or its ability to move spontaneously and independently. The beef producer can evaluate the first part and a veterinarian should conduct the remaining parts of the exam.
A body condition score of 6 is the ideal target prior to the start of breeding season. That is on a scale where 1 is emaciated and 9 is very obese. Body condition can be affected by length of breeding season, number of cows the bull is expected to service, grazing and supplemental feeding conditions, topography (marsh, hills, etc.) and the distance required to travel during breeding. Ideally, bulls should have enough fat cover at the start of breeding season so their ribs appear smooth across the sides.
When selecting herd bulls, emphasis is placed on growth performance, EPDs, and soundness. These are all vital criteria and no one should purchase or use a bull for breeding that is lame or unsound. Sound feet and legs are very important because unsound bulls have trouble travelling and mounting cows for breeding. There are times when some bulls may even need a hoof trimming a month before the breeding season. A bull has to travel a lot of miles so he should have the best wheels (feet) possible. Also, the general health of the bull is critical since sick, aged and injured bulls are less likely to breed and usually have lower semen quality which results in lower conception and calving rates.
The external examination of the reproductive tract includes evaluation of the testes, spermatic cords and epididymis. Scrotal circumference is an important measure since it is directly related to the total mass of sperm producing tissue, sperm cell normality and the onset of puberty in the bull and his female offspring. Bulls with large circumference will produce more sperm with higher normality and also reach sexual maturity sooner. Examination of the external underline before and during semen collection will detect any inflammation, foreskin adhesions, warts, abscesses and penile deviations. The internal examination is conducted to detect any abnormalities in the internal reproductive organs.
The semen evaluation is conducted by examining a sample of the semen under a microscope. The veterinarian will estimate the percentage of sperm cells that are moving in a forward direction. This estimate is called motility. In addition, the sperm cells will be individually examined for proper shape or morphology. Less than 30 percent of the cells should be found to have an abnormal shape. The effect of semen quality on fertility is well documented. As the percentage of quality semen increases, the percentage of conception rate increases.
The cost of BSEs varies depending on a number of factors, including location of the test (on the farm or ranch versus the clinic), the number of bulls tested and facilities available. No matter what the cost, the cost of a breeding soundness exam is cheap insurance when compared to the cost of open cows or calves born late in the calving season.
The LSU Agricultural Center is a statewide campus of the LSU System and provides equal opportunities in programs and employment.