How does Valu-Bull carry out breeding examinations?

We may be ending calving season, but it’s never too early to think about breeding season. With the breeding season comes scheduling those bulls for their reproductive health screening (BSE) and making sure your battery of bulls are satisfactory sires.

Reproductive soundness examination

The American Society for Theriogenology has developed minimum guidelines for a bull to be classified as a satisfactory breeder. A veterinarian will evaluate the bull on the following criteria: a physical exam, measurement of scrotal circumference, and will assess semen quality for motility and morphology. To pass a BSE, a bull must have at least 30% progressive motility (is the individual sperm moving in a forward progression), 70% normal sperm morphology (are there problems with sperm formation) and a minimum scrotal circumference based on age. If a bull does not meet the minimum requirements, he is either classified as deferred (meaning it is recommended that the bull be re-evaluated) or as an unsatisfactory potential sire.

The scrotal circumference tells us the testicular mass. As it increases, the daily production of high quality sperm also increases. Scrotal circumference is also an important measurement because it is directly related to the onset of puberty in the bull and its female offspring.

The physical exam is an important part of a BSE. Bulls should be athletic, with healthy legs and feet, excellent eyesight, and adequate physical condition. The demands of the breeding season are extreme and bulls must be able to maintain their physical condition throughout the season.

Value of an ESB

Ideally, we like to encourage producers to test bulls around 4-6 weeks before breeding season to ensure they are satisfactory sires. This delay allows sufficient time for the producer to identify a new bull for breeding if necessary. If damage to the scrotum during the winter (for example, frostbite or wounds) or other injuries to the bull are identified, it will be essential to give them enough time to recover. Sperm production is a 61-day process, so wounds that occur in March-April may persist into May-June. An ESB is a one-time measurement, so it will be important to give yourself enough time to update your bull battery.

What is the benefit-cost ratio of an ESB? Here’s a scenario: Farmer #1 avoided BSE during the last breeding season. His exposed female to bull ratio was 25 head and he weaned 85% of his calf production at an average weaning weight of 560 pounds – which adjusts to 476 pounds per exposed cow. If he sold the weaned calves at $170/cwt, he earned $809.20 for each calf per cow exposed. The following year gave the same weaning weights and show ratio, but he tested the bulls. As a result, his crop of weaned calves increased to 87% as he identified and selected fertile bulls by having BSE performed. This gave him an average weaning weight of 487 pounds per cow exposed and $828.24 for each calf, resulting in a change in gross revenue of $19.04. The cost of BSE was $65 per head (includes examination, transport and labor), which works out to $2.60 for each exposed cow. This gives us this: $19.04 (revenue) – $2.60 (cost) = 7.32 benefit-cost ratio. In other words, for every dollar spent on BSE, he earned $7.32. It’s a great insurance policy!

To assess your benefit-cost ratio on your bull battery, here is a great resource from Texas A&M AgriLife Extension: [excel spreadsheet]

Considerations Beyond BSE

Stocking rate is the number of cows a bull can successfully breed. The national average stocking rate is twenty-five cows per mature bull or fifteen cows per yearling bull. In some systems, stocking rates of up to fifty cows per bull are used, but high stocking rates can result in late calving due to missed heat cycles. Additionally, bull libido (willingness to reproduce) can only be determined when bulls are on pasture or in paddocks with females in heat. Bulls may have all the qualifications to pass BSE, but if they are not actively breeding cows, producers should find different options. Taking the time to observe reproductive activity allows for an earlier opportunity to catch and correct potential problems, which is much more cost effective than waiting for open cows to calve.

Source: University of Nebraska-Lincoln, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all of its affiliates are not responsible for any content contained in this information asset.