5 reasons why your bull may not be up to the job!

Whether you are using your bull as a sweeper on a dairy herd, a group of heifer replacements, or as your primary source of pregnancy in a suckler or dairy herd, the consequences of a male with reduced fertility can be disastrous for your business. Imagine getting to scanning day and finding out half your herd is still empty? Or even worse, none of the cows is pregnant? Now imagine getting to that point and realising there was something you could have done to prevent it. It is commonly said that bulls are 50% of fertility. In reality, they are a lot more than that – if 1 cow is infertile, that cow will not get pregnant. If 1 bull is infertile, you could be looking at 50 empty cows. This post will cover 5 reasons why it is vital to check your bull’s fertility regularly.

5 Reasons To Check Your Bull

1. Over 25% of bulls tested are not fertile

A study of 858 bulls that underwent breeding soundness exams found that 229 were either deferred for a retest as they had an issue that may resolve with time or were unsatisfactory and unlikely to ever reach peak fertility.

Some people rely on numbers – if 25% are infertile, they will run 4 bulls rather than 3 with a group. This will not eradicate the risk – if a bull is keen, yet his semen quality is low, he may be serving cows and keeping the other bulls off without getting any female pregnant. You may not end up with all your cows not pregnant, but you will have fewer pregnancies quickly than if all bulls are fertile.

2. It’s not just old bulls that fail

The results weren’t great for older bulls, with over 30% of bulls over 4 years old failing. But they weren’t much better for younger bulls either, as the chart below shows. You can’t just rely on a young, well-grown bull to be fertile.

Influence of age on pass rate of bull breeding examinations performed

by Westpoint Farm Vets

Almost 1 in 5 bulls at each age group would be a liability to the success of your herd fertility. That is a considerable risk to take.

3. It’s all about the physical!

Almost half of the bulls that failed had issues on a physical exam. That may mean something that we know is associated with reduced fertility, such as a small scrotal circumference, or it may be something that will stop the bull from effectively doing his job. If he has bad front feet that are causing him pain, he will be less keen to mount cows. Your bull should be a performance animal, and a thorough physical exam before going to work will pick out a lot of problems.

You may have suspicions about some of these things – if the bull is only standing on 3 legs, it needs rapid treatment and will be out of action for a while. Others may be subtle changes that only an experienced practitioner will be identified – how often do you look at the end of bulls’ penises?

4. The problems you can’t see!

For every bull that fails on a physical exam, another one fails purely on its semen analysis. That may be a low sperm count or sperm that do not swim very well. Either way, this is where the Dynescan comes in. For the first time, there is a way to quantify and put numbers to the quality of the semen in the field. It is no longer about a pass/fail based on looking down the microscope and scoring from 1 to 5.

5. Can you afford the consequences?

My father once said to me, “only get insurance if you legally have to or you can’t afford the consequences”, and whilst that may work out okay as an approach over a lifetime, can you afford the consequences of an infertile bull? Not many businesses can! So, find out whether your bulls are up to the job before each breeding season. 

So if you are using a bull and choose not to get the bull tested annually, you are effectively taking a 20% risk, with consequences that could be disastrous for your business. When you can’t see half the problems, the only way to ensure success is to get your bulls tested and use Dynescan to ensure a reliable, repeatable assessment of semen quality. 

If you would like to know more, please go to www.dyneval.com/dynescan and ask your vet for the only on-farm automated semen analysis equipment on the market. If they don’t already have a Dynescan, we would be happy to speak to them about it. 

The full study results can be found at westpointfarmvets.co.uk

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