Will I know if my bulls are working successfully?

Will I know if my bulls are working successfully?
By Fiona Mcleod, Veterinarian & part of the Anexa Bull fertility testing team, Anexa Vets Te Kauwhata

Maybe, but not until it’s too late. If he is lame and not mounting, has low libido or cannot penetrate then it is likely that astute staff will notice that. However, 10% of the bulls we fertility test fail for those reasons that are not outwardly obvious, here are some of those reasons:
  • Bull size: A poorly grown R1 bull that hasn’t reached puberty does not produce mature semen and won’t get cows in calf. This was a problem last year and given the drought, may be this season also. Our bull fertility team are used to looking at good bulls of all different breeds, so they have their eye in on what is a well-grown bull.

  • General health: Scrotums are designed to hang low and keep testicles cool. So any rise in temperature associated with lameness, pink eye or a passing infection can result in temporary sterility. It can take 60 days to produce new sperm and be fertile again!

  • Scrotal size: Size does matter! There is clear and repeatable evidence that bulls with small testicles produce less sperm than those above a set size (adjusted for age and breed).

  • Genital lesions: Corkscrews, genital warts, injuries and scars that keep the penis in its sheath are more common than we think. Our bull fertility team have seen it all!

  • Internal lesions: Our semen exam includes rectal examination of the accessory sex glands. Inflammation of these cause poor fertility, usually without clinical signs. This may also affect your cows as the ejaculate is full of pus and can cause vaginitis after mating.

  • Semen: Many young bulls produce an ejaculate that contains no or few sperm. Many of the bulls we fail produce a good looking sample where the sperm are all dead. Some are subfertile (some live sperm but just not enough), some are swimming in circles due to defects and some just don’t swim. None of this is apparent without a semen exam. Don’t wait until scanning time to find out!
Talk to your Anexa vet about whether bull fertility testing is a good option for your herd and heifers. To undertake a bull exam you need a good head crush and vet race to load the bulls. Therefore, the better option may be to speak to your bull supplier and we test them before they leave their farm. We can also do any disease testing and vaccinations required at this time.

Date Added: Thursday, 3rd September 2020