By Dave Warburton
Veterinarian, Vet Services HB Ltd

The stud bull sale season is upon us, and coincides with the end of pregnancy testing of the cow herds.

How did the cow herds scan this year you ask? In general we have seen cow herds in great condition and this has seen fewer cows due to calve late in the calving period.

Dry rates are still around our usual 5-10% range. Heifers are in good condition with standard dry rates averaging 10-12%, with the odd but not uncommon disaster in each age group.


When purchasing a bull, it is always reassuring to know that the breeder has produced a product which has been verified at some stage to confirm fertility.

The gold standard for bull fertility testing is to make sure that;
1. The bull is producing good semen – via a semen test
2. The bull is able and interested to breed a cow/heifer – via a serving ability test
3. The bull is free of disease and vaccinated appropriately – via a BVD blood test (negative result) and a BVD vaccination course preferably alongside clostridial and leptospirosis vaccination protection.

Make sure you talk these tests through with your bull supplier.

If the breeder ticks all of these boxes they have done all they can to produce a fertile bull. However, as we know things can change, and the fertility of the bull with these tests is only a guarantee on the day of the test and not a guarantee for the future.

This means it is your responsibility as the new owner of the bull to make sure he is still and remains healthy, in good body condition and also fit and toned up to do the job he was purchased for.

All breeding bulls should be on an exercise programme six weeks out from mating. That means putting them in a paddock of similar contour country to what they are expected to cover during mating (ideal if the trough is at the top of the hill).

Fat bulls are generally lazy bulls and more at risk of breaking down and less willing to seek out females, especially in big paddocks and big country.

A bull's fertility can change if he becomes lame, loses condition, has a big feed change, is heat stressed or is exposed to a new disease.

An annual check up for breeding bull's pre-mating in the spring is a great WOF and provides peace of mind that the bull is capable of doing what he is there for and helps avoid unwanted disasters (not caused by injuries), which are usually found out when it's too late.