Bull Testing

Whilst it is important to ensure your cows are in good condition and have plenty of feed, it is also vital to remember the other key player in your mating success - bulls. 

Complete health should be on target and they should not be suffering from any disease or illness. Even a small ailment like a foot abscess can disrupt sperm production for upto 8 weeks. There is one major aspect of a bull’s health that can’t be assessed externally - semen. How do you know if those swimmers are actually going to swim? The annual herd pregnancy scan often comes up an unexpected high dry rate - this could be due to an outbreak of silent diseases such as BVD or Vibro, but often is linked with a bull subfertility issue.

Unfortunately, it is often too late to do anything about the problem if it was only found at scanning time, which can be very costly to your business and the genetic progress of your herd.  Bull testing including semen motility morphology is best done2-6 weeks prior to mating or sales. Prior to mating to be representative of current bull fertility. When a vet comes out to do a breeding soundness exam on your bulls, they will do a physical exam, checking conformation, testicle palpitation and measurement. An internal and external reproductive exam is also performed. The semen is collected and assessed microscopically for motility and morphology.

At the time of bull testing we can award a pass, fail, pending morphology assessment. Anything that raises the body’s temperature, even for a short time, can damage sperm production and subsequent fertility. The lifecycle of a sperm is approximately 60 days, therefore it can take up to two months for a bull to recover to full breeding capacity after disease or injury. It is also important to ensure the herd has been administered their Vibrio vaccine at least 4 weeks before mating.

If you are relying on your bulls to impregnate you need to know they will ‘get the job done’ prior to mating start date. To give your cows every chance to succeed at fertility, contact the clinic to speak to one of our large animal vets to arrange a field visit or if you require more information.