Raising healthy bulls key to reproducing power

Dr. Colin Palmer is the Associate Director of the University of Saskatchewan, Livestock and Forage Centre of Excellence in Saskatoon. He and his family also own and operate their own herd of Red Angus cattle near Dundurn, Sask. Dr. Palmer is a theriogenologist (specialist in animal reproduction) practicing in western Canada for many years.

“No producer wants to buy a fat bull but just try to sell him a skinny one.”

The investment in a herd sire is often a large purchase for any cow-calf operation. To ensure this investment will remain in the herd, breeding bulls must be properly maintained during and between breeding seasons. Whether you are a commercial cattle producer looking to purchase a new herd sire or are a purebred operator who is developing bulls for sale, over-feeding is one of the biggest issues when it comes to young bull management, says Dr. Colin Palmer. Pushing young bulls for large daily gains can lead to issues such as joint effusion (swelling), laminitis, acidosis, inflammation of the seminal vesicles, and over conditioning or simply becoming too fat.

Overly conditioning bulls can have a direct impact on their performance as a herd sire. Fat deposits in the neck of the scrotum can harm the cooling mechanism of the testes which can impair temperature regulation (both warm and cool). Palmer says this can lead to a reduction in testosterone and potential loss of sperm production in the testes.

Palmer says poor performance can also be a result of underfeeding bulls, particularly in mature bulls. “A balanced diet including salt and minerals is important for preparing mature bulls for the next breeding season. Feed testing is vital to ensure the proper nutrition is being met.”

Breeding Soundness Evaluation Bulls that fail a breeding soundness evaluation may be re-tested a few to several weeks later. Palmer says any bull that is not fertile at the beginning of the breeding season, regardless of the cause, is a liability for the cow-calf producer. Palmer also notes that although a bull may fail a Breeding Soundess Evaluation (BSE), this does not necessarily mean the bull will never pass the test in the future.

Stressors such as lameness, sudden temperature changes, and illness can negatively impact a bull’s ability to pass the BSE. He suggests testing bulls that failed the BSE initially to re-test a few to several week later depending upon the types of sperm defects present.

Bulls believed to be capable of passing the BSE in the near future may be given a “decision deferred” or “questionable” classifications. Decision deferred is preferred for young bulls intended for a bull sale but just need more time to mature.

Some causes of poor fertility may be genetic or due to a severe injury to the reproductive organs. Unfortunately, in many cases these occurrences may result in very long lasting or permanent poor fertility and these bulls are classified as unsatisfactory. Poor semen quality of course is only part of the picture – a satisfactory bull must also be able to mount and complete service. Palmer says producers may want to consider buying the ‘full meal deal’ when it comes to purchasing bull insurance, which includes the full fertility coverage.

Bull Housing, Health/Biosecurity Palmer says adequate bedding is necessary to prevent frostbite on the testes which can negatively impact a BSE. He suggests easing bulls together into a new environment at the same time is helpful when establishing social dominance.