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Friday 20 January 2017

Critical elements to consider before selecting new bull

Beef

Peadar O Scanaill

Published 01/11/2011 | 05:00

The beef bull is well finished his covering season and will be housed quietly away to one side for the winter months. On some farms, with the price of beef at an all-time high, there is a strong temptation to change an older bull with a view to buying a younger model.

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We would be well to check out a few items before bringing a new bull onto the farm:

•First and foremost, we should source a bull that does exactly that which we need on the farm. Often we see a seriously oversized bull and may judge him to be bigger and better than the rest. But just because he's a big fella doesn't always mean that he will produce good calves.

We must also bear in mind how big an off-spring we are trying to produce. Is the bull to cover mature cows only, or will he be used on replacement heifers as well? Difficult calvings and caesarean sections are not the order of the day and should be avoided at all costs. Easy calvings must be high on the agenda.

•We should look on a new bull as a potential Trojan horse. I use this term as I refer to the disease status of the new bull.

Although he himself may look healthy, he could be coming from a herd that carries Johnes, BVD or some such disease. The Trojan horse description comes into play if an outwardly healthy bull is mixed in with all the breeding females on the farm and slowly or quickly passes on IBR or BVD into the very centre of the herd.

To avoid this we should check a few things before purchase. The new bull should be sourced from a Johnes-free herd that has an ongoing Johnes monitoring programme in place. The bull should be blood tested for IBR and BVD. He should be virus-free and PI negative on a blood test in the case of BVD.

Before the bull enters the farm he should be fully vaccinated including BVD and IBR, and leptospirosis as a starter.

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He should be treated for fluke, rumen fluke, worms, lice and mange before he comes in contact with animals on his new farm. A footbath to treat mortellaro or other foot infections should be used for the first few days on farm.

•And we should also remember that this guy is going to need a couple of weeks to settle into a new routine upon arrival. He should be kept to one side on the farm and allowed to mix with one female who will not bully him.

This is especially true in the case of a young bull. All too often, a new bull is purchased just at the beginning of the breeding season, and is not given time to acclimatise.

Dominant

If he is young, he may meet a particularly dominant female and fail to assert his dominance in the new group. He'll fail to thrive and won't cover some of the bulling females. Fertility in the herd will suffer and the whole process becomes a failed experience.

•Feeding on arrival is also important as some of these animals are on a very high plane of nutrition.

Therefore we should feed concentrates in the first few weeks and slowly bring him from his previous food intake to what his intended intake will be when running with the main herd.

•A bull's fertility is of paramount importance, and sometimes we can run a few checks before purchase. If a mature bull is being purchased, he is likely to have covered cows in the past. Pregnancy rates and live calves born to the bull can give a quick guide to fertility. With younger bulls, this information is not available, so if required, a fertility test can be carried out.

This involves your vet doing a full clinical examination of the animal, with special emphasis on the external genitalia. The vet checks the testicles, the scrotum and the glands along the penis for any signs of abnormality. A semen sample can be obtained if the new bull is mature enough. In years gone by, this was a difficult experience, and involved the use of bulling cows and an artificial vagina. It was difficult and dangerous, and therefore rarely done.

Nowadays, a semen sample can be obtained by the vet on the farm or at the clinic with the use of electro-ejaculation.

The resultant sample is quickly assessed by the vet using a microscope and some laboratory equipment, giving a very accurate read on the bull's fertility. If all of that seems too difficult to organise, then one can only rely on retrospective information.

Your new bull should be able to cover about 50 females over a three-month period, getting up to 60pc in calf in the first three weeks, with up to 90pc in calf over the full three months. The trouble with the information obtained is that the bull is well established on farm by this time, and an infertile or sub-fertile bull has just wasted your breeding window.

To finish, please remember that a new bull is something that should be planned and introduced carefully. Any new animal coming on to farms should be quarantined before entry and checked for diseases before mixing with the herd.

The bull should be returned if the checks don't come up with the right answers. The fastest way to introduce a nasty disease on to our farms is to buy in an animal carrying such a disease.

Sin an méid anois!

Peadar Ó Scanaill is in mixed practice in Ashbourne Co Meath and is a member of the Food Animal Group of Veterinary Ireland. Email: HQ@vetireland.ie Tel: (01) 457 7976

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