A stock bull is a big investment but, on a lot of farms, pedigree bulls don’t last long enough to recoup their investment.

While some will blame heavy feeding in early life, the reality is that young bulls aren’t looked after well enough, especially in their first season at work.

While some excessive feeding does take place in some herds, it is the purchaser who calls the tune here.

If these overfed bulls were left without buyers, things would change very quickly in terms of getting bulls ready for sales.

Feed management

The management of a newly purchased bull post sale is very much linked to the animal’s diet prior to the sale.

There have been many figures thrown about as to what pedigree bulls are getting in the buildup to a sale, varying from 1% to 2% of live body weight depending on breed.

So, given a 700kg bull, you would be looking at 7kg to 12kg of concentrates per day.

Over-condition will depress fertility

For this reason, purchasers should make themselves aware of the feeding regime of the bull and, secondly, allow adequate time to get that bull to a “fit not fat” condition before breeding commences.

Over-condition will depress fertility. Bulls should be gradually decreased from the show diet over a period of time. Again, this is dependent on when the bull is needed and how long the purchaser has the bull beforehand.

Gradually decreasing the amount of concentrates that make up the diet will also help to reduce the risk of problems in the rumen. Rumen microbial populations need time to evolve to new diets.


They will likely be changing from predominantly starch digesters to forage digesting bacteria.

This process takes time to change. Abruptly changing the diet will lead to a situation where the animal can’t absorb nutrients, leading to excessive weight loss and stress.

It is also advisable to get information from the vendor regarding the constituents of feed the bull was on before the sale as this again will aid in a problem-free transition in the diet.


Many pedigree breeders now look at fertility testing young bulls before sales as common practice, both for their own peace of mind as well as the purchaser’s.

Lameness, stress, fever and even exposure to disease can all lead to temporary infertility in a bull

But buyers should be aware that many different factors can affect semen production and quality after that on-farm test.

Lameness, stress, fever and even exposure to disease can all lead to temporary infertility in a bull. In many cases, these factors can all be avoided with proper management post purchase.

While best efforts may have being taken to acquire a bull from a high health herd, risk still remains.

Having purchased a bull either privately or at a sale, it is best to isolate the animal on arrival for testing and acclimatisation.

Having an animal, especially a young bull in isolation, can lead to aggressive behaviour so it’s best, if possible, to pen with a cull animal already in the herd.

This way, if the bull were to fail any common disease tests, it would only be an animal already destined for slaughter which stands the risk of being infected rather than the entire herd.

What tests should he pass?

Bulls should always be clear of bovine viral diarrhoea (BVD) virus. This is compulsory since the introduction of the BVD Eradication Programme in Ireland in 2013.

In addition, many farmers have tests carried out on newly purchased pedigree bulls to ensure that they are free of disease.

Despite bulls having clear BVD tests in their infancy, some farmers take no chances and test for BVD again, in case bulls were exposed to a persistently infected (PI) animal at any stage.

Other tests for diseases such as Johne’s, infectious bovine rhinotracheitis (IBR) and leptospirosis are also routinely undertaken on pedigree farms, with many of these farms accredited.

The minimum the new purchaser should be testing for relates to what their specific herd is testing for or previous issues the herd may have had.

Vaccination programmes are vital when purchasing a new bull. Where a bull may have tested clear of a disease and a breeder has chosen not to vaccinate, this bull’s exposure to a herd with disease can lead to a period of infertility.

The IBR strategy for the entire herd needs to be consistent to avoid risk

While the bull will likely regain full fertility following this period, it can prove particularly harmful to the herd’s calving pattern.

Where a herd is using the live IBR vaccine, it is essential to vaccinate the bull upon arrival, as a period of stress with exposure to the low levels of inactivated virus in other animals could lead to the onset of IBR in that individual.

The IBR strategy for the entire herd needs to be consistent to avoid risk.

Individual vaccine programmes should be discussed with your vet.


Libido can be affected by social ranking, lameness, back pain and other unknown factors, so all bulls should be observed closely at the start of the mating period to ensure that they are showing normal libido.

Young bulls shouldn’t run with too many cows in their first year.

Fifty cows should be the maximum number for a mature bull

A general rule is one bull can service as many cows as he is months old, eg a 15-month-old bull should service a maximum of 15 cows, a 20-month-old bull should service a maximum of 20 cows, etc.

Fifty cows should be the maximum number for a mature bull.

Breed young bulls for a maximum of 60 days in order to prevent overuse, severe weight loss and reduced libido.