Bull selection
The right bull selection will have a major effect on herd fertility.
Bulls contribute 50% of the genetics of offspring and are an essential and expensive part of the breeding herd. Bulls drive the market for offspring and the genetic future of the herd.
There are many important things to consider when selecting and purchasing a bull. Purchase bulls with a veterinary certificate of soundness. Also consider health status, vaccinations and the area of origin.
Many smallholders don’t keep a bull of their own and it is common to loan a bull from a larger enterprise or neighbour. Ask the owner about the bull’s soundness as outlined below. Ideally view the bull before agreeing on the loan arrangements. If you don't have safe restraint facilities on your property, consider asking to have the bull vet checked and disease tested on the owner's property before you loan him.
It is imperative to consider biosecuritywhen loaning a bull– complacency can lead to failures in pregnancy and could have long lasting implications.
Assessing bulls for joining
What to look for when selecting bulls for breeding:
Conformation and feet
Inspect knees, hips and feet—very straight or very angular conformation can result in early joint damage and arthritis. Watch the bull walk around—stringhalt (locking of the kneecap) is sometimes seen in bulls with Bos indicus content. Look for bulls that stumble on uneven ground as it usually indicates some musculoskeletal problem. Check the feet carefully. Fibromas (foot warts) are common in many bulls. Unevenly grown claws usually indicate uneven weight bearing and may indicate joint pain. Corkscrew claws and scissor claws also appear to be heritable and should be avoided. Avoid inspection in muddy yards as it will be difficult get a good look at the feet.
Reproductive organs
Watch for sheaths that hang low and close to the ground as they can be easily injured. Testicles should be free of lumps or swellings and equal in size.
Bulls with a high scrotal circumference have greater fertility and have daughters who are more fertile. Aim for 29 cm at 2 years of age in Brahmans and 27 cm at 15–18 months of age for British and European breeds.
Age
Young bulls (18 months to two years) are quite fertile, but inexperienced. By using bulls earlier, you can increase the working life and uptake of the new genetics and save money, but they are also prone to more injuries because they mount more often than older bulls.
Diet
Be careful about grain-fed bulls. They may not do as well on an all pasture diet and need time to adapt before joining. Bulls should not be more than condition score 3.
Serving
If it is possible, observe the bull trying to serve. Spiral deviation and persistent frenulum are two common penis problems that can only be detected with the penis extended. Spiral deviation is seen most commonly in polled breeds (up to 20%) and can increase with age.
Temperament
Bulls can be very dangerous, so selection on temperament is important. Bulls will also influence the temperament of their offspring.
Bull soundness and genetics checks
Unsound bulls can set a breeding program back a long way. There are a range of tools and health checks to assist.
Bull Breeding Soundness Evaluation
Breeding soundness examinations ensure your bulls meet the minimum standards for fertility and reproductive health. The Bull Breeding Soundness Evaluation (BBSE) is a uniform method of assessing a bull's likelihood of accomplishing pregnancy in an appropriate number of open, healthy, cycling cows or heifers during a defined breeding season.
The BBSE includes a semen exam to evaluate sperm motility and morphology as well as a physical exam. The bull is evaluated for overall structural soundness, reproductive development, testicular size and health, and the physical characteristics of the bull including mobility and athleticism in the pasture.
Estimated Breeding Values
Estimated Breeding Values EBVs provide estimates of the likely performance of the bull’s progeny for a variety of genetic traits. These include growth, feed intake, milk, fertility, carcase, temperament and soundness. They are based on performance records for the individual bull or their relatives (parents / progeny).
EBVs are calculated by using BREEDPLAN, an advanced genetic evaluation system which uses computer analysis of pedigree and performance information. EBVs separate the influence of environmental factors such as nutrition, as well as age and sex, which allows comparisons between different localities. They are available for many bull sales and are listed next to the number on the catalogue
Veterinary certificates
When buying bulls, always ask for a veterinary certificate. The veterinarian soundness certificate addresses the following:
- conformation and mobility
- examination of reproductive organs — testes, penis, seminal vesicles and scrotal circumference
- semen quality assessment — sperm count, mobility and shape
- serving ability — serving capacity tests.
Health considerations
Bulls are a valuable investment, so it is worth being vigilant for the following diseases and seasonal health management.
- Purchase bulls that are tested free for pestivirus and with a reduced risk of bovine Johne’s disease.
- Vaccinate for vibriosis, seven-in-one, three day sickness, botulism and pestivirus.
- Worming – quarantine drench on arrival and hold in yards for several days before putting in paddock. After calves and weaners, bulls are the most susceptible cattle on farm to worms.
- Ticks – treat on arrival to farm to reduce the chance of introducing cattle tick.
- Buffalo fly – bulls generally carry more flies than cows and should be treated as needed.
Better bull buying webinars
Watch or listen to our informative online webinars.
- Bull selection decisions for Heifer matings
- Southern Multi Breed Project Update
- Managing Bulls to Ensure the Genetics Work