Do you ever ask yourself questions like;
- How many bulls should I run?
- Are my bulls sufficiently fertile?
- Should they be vaccinated?
- Could bulls be spreading disease through my herd?
- Will the bulls make it through the season?
If you’re asking yourself any of these questions, maybe it’s time to consider the benefits of a bull breeding soundness examination (BBSE).
Whether they’re the primary method used to get cows in-calf or following AI, bulls play a vital role in your farm’s reproductive performance.
Due to the fact such low numbers of bulls are used for the number of cows, they are a key risk point in your reproduction program.
A recent study conducted by The Vet Group, and validated by other trials, indicates that 20% of bulls will fail a pre-joining check, and 37% do not pass at the end of joining. In other words, 1 in 5 bulls don’t make the grade.
A bull breeding soundness examination involves two main components; firstly a physical examination and secondly an assessment of semen quality.
The physical component involves assessing the ability of a bull to seek out and serve females on heat. This is done by assessing the head, gait, feet and legs of the bull to identify any potential risks to his serving ability.
The reproductive organs of the bull are also examined – the testicles, internal genitalia, penis and prepuce. Any abnormalities in this region are highly likely to be risk factors for infertility.
Semen is then collected and assessed immediately for the level of activity and a sample is sent to the lab for assessment of sperm shape. Both of these factors have been shown to have a strong association with a bull’s fertility.
The pre-joining VBBSE has long been a routine practice performed in the beef industry and has been shown to significantly reduce the risk of a bull team performing poorly.
Whilst the use of bulls in our industry is different, they still have an extremely important job to do. Here, the old adage is definitely true – if you don’t look then you won’t know!
Sperm take about 70 days to develop in the testes, so any infections or inflammation that result in a high testicular temperature during mating have the potential to reduce a bull’s semen quality and therefore his fertility for an extended period of time.
Bulls should be observed daily during the mating period to check for signs of illness, lameness and loss of libido.
Rotation and replacement of bulls is important to reduce fatigue and reduce lameness over the period the bulls are being used. The power of the bull team comes from having an adequate number of bulls available to serve the expected number of cows on heat.
The current recommended ratio of bulls to cows is 3 per 100 cows to be joined (at the start of AI) and 4 per 100 if synchrony is used.
Always have more than one bull in at any one time.
All bulls which are to be used should be vaccinated to prevent vibriosis. Vibriosis is a venereal disease spread by bulls to cows and heifers during joining.
There are no clinical changes in the bulls, but infection of females causes early pregnancy losses.
Vaccinating the whole bull team 2-4 weeks prior to joining every year is an effective prevention method for the whole herd.
Bulls should also be ear-notched to confirm that they are not a carrier of Bovine Viral Diarrhoea Virus (BVDV) infection. BVDV can have a significant effect on fertility and result in abortions and abnormal calves.
A good game plan for your bull team
Pre-Season Training
- Have bulls on farm and grouped 2-3 months before joining – bulls need time to sort out their social hierarchy
- Aim to have them in moderate body condition – not too thin or fat
- Drench & vaccinate (5/7 in 1, Pestigard, Vibriovax)
- Supplements! Additional vitamins and minerals which are specific to your farm or area
- Feet – consider placing blocks on your bulls’ feet prior to joining to prevent lameness – The Vet Group can use the portable tipper crush to do this for you
Pre-Season Fitness Test
- Call The Vet Group to arrange a Bull Breeding Soundness Evaluation 2-4 weeks prior to the bulls going in
During the season
- Pick your team – ensure you have the correct number of bulls
- Manage your roster – rotate your bulls to give them a break
- Watch the game – Observe your bulls daily to assess for injuries and libido
- Use your bench – Sub out any lame or injured bulls
