Bull Vasectomies- a cost effective way to improve fertility figures?
We are all striving for better fertility figures during a time when there seems to be a
continual decline in reproductive performance. The major factors influencing reproductive
efficiency are heat detection rates (hence submission rates) and conception rates.
Reproductive efficiency= Heat detection rate x Conception rate.
It is difficult to influence conception rates easily with the National average being in the
region of 35-37%.
Where we can make a significant difference is the improvement on Heat Detection Rates.
The National average for heat detection rate remains at about 55% and has done for the
past 15-20 years. It has become more difficult to spot cows bulling due to time constraints,
larger herd sizes and due to breed/yield cows display signs of oestrus for a much shorter
period.
There are many aids to heat detection. These include the use of heat mount detectors, tail
paint, pedometers, closed circuit television, vaginal probes to assess electrical resistance,
and milk progesterone assays. While they are all effective, their uptake is not universal due
to problems associated with their use.
One comment that has been made to me on at least two occasions over the last three
months is that when the bull has been turned out with the cows that they appear to come
bulling more strongly. With this in mind I have read several articles where young bulls have
been vasectomised to help with heat detection and they also appear to “stir” the cows up a
bit. I have performed bull vasectomies in the last practice I worked in. There were a number
of small holdings and the farmers had another job to supplement income so couldn’t spend
enough time during the day to watch the cows for signs of oestrus.
The use of a vasectomised bull offers the advantage of improved heat detection while
maintaining control over breeding.
Bull Selection
Due to size and relative ease of handling it has been suggested that an Angus or Hereford
cross makes a good candidate for vasectomy.
The bulls would be vasectomised at around the age of puberty (9-10months) and they
would be put to use once of a reasonable stature.
The bulls would be fitted with a chin-ball marker which needs to be topped up with paint on
a regular basis (usually weekly).
The following guidelines have been suggested re the number of bulls required and the
length of time that they should be run for...
Herd size Calving pattern Bull use
Up to 200 cows All year round Single bull, intermittent use.
4 weeks on 2 weeks off
Up to 200 cows Block calving Single bull use from 6 weeks into the
breeding season
More than 200 cows All year round Two bulls, swap over every 2 weeks
More than 200 cows Block calving Single bull use from 6 weeks into the
breeding season
I would always be tempted to have at least two bulls vasectomised just to have a back-up
plan for unforeseen illness and lameness issues or low libido.
So Is It Cost Effective?
In one study, written up for the M.D.C. by Mr Paddy Gordon of the Shepton Veterinary
Group, Somerset, proved that the use of a vasectomised bull proved to be very cost
effective. Vasectomised bulls were used on 6 farms in that area and different parameters
were used to measure the degree of success.
1. Submission rates
The most significant improvement was seen in the increase in submission rates which
overall improved by 10% (from 64% to 74%). On many of the farms this increase was as high
as 15% but the overall figure was compromised by a bull which had a very low libido.
2. Calving to 1st serve interval
The presence of the bull resulted in a reduction of calving to 1st service interval but this
varied depending whether the herds were seasonal calving or all year round (in the latter
case the reduction was 5.4days).
3. Conception rates
There was no significant difference in conception rates during this trial.
In conclusion the data from this trial was compared to the National Averages
Parameter U.K. average Vasectomised Bull Vasectomised bull
value Figure effect
Calving – 1st service Minus 5.4 days
Submission rates 55% 65% Plus 10%
Conception rates 38% 38% None
Reproductive 20.9 24.7 Plus 3.8
efficiency
The overall conclusion from the trial work done was that there was a definite cost benefit.
Once all the figures were entered with respect to cost of vasectomy, feeding cost,
equipment costs (chin ball marker and paint) and that was then balanced with the financial
gains such as a reduction in calving interval, reduction in culling for fertility and final sales
cost of bull there was a 500% return on the initial investment.
If you have any questions re the use of Vasectomised Bulls please phone the surgery and
speak to one of the farm team.
Ian Patton
