Gillian O’Sullivan: How to safeguard your herd health when buying in a bull

AI bulls have been selected but our own beef stock bull, Jerry, recently took his retirement after four seasons of mopping up. Bull fertility declines from around five years of age, so four mating seasons from any mature bull is about enough.

This also reflects workload, and being a seasonal-calving dairy herd, stock bulls must be on their toes.

Usually, we kept Jerry in a small paddock around the parlour and once breeding began, he would entertain a few cows that were in heat over the first few weeks that were let in with him after milking.

Generally, he was very efficient, his job completed in a timely manner, and the cow was happy to exit after a brief but successful encounter. This allowed us to judge his libido and conception rate in an easy way before the main body of work was to begin.

Once performance was good, Jerry ran with the herd from around week 5-6 of mating with back-up from a young dairy stock bull, and they mop up for 35 days. There was a slight drop in his usual, blink-and-she’s-in-calf routine last year so a new kid on the block had to be sourced for this season.

Over the past 10 years we have built a good relationship with a local Hereford bull breeder and we have been rewarded with fit, robust bulls that perform well on a very hilly farm. The breeder makes a point of rearing hardy bulls that are out-wintered and always look lean and athletic.

When choosing a bull my father has taught me one thing: find one with some length to him. This has generally served us well. We operate an almost closed herd, with a bull purchase being the only exception.

Being a vet, the lectures around biosecurity are ingrained within me, so a significant level of thought goes into reducing infectious disease risk associated with stock purchases.

As a general rule, you should buy as few animals as possible from as few herds as necessary. We only have a single bull purchase once every 4-5 years and we source from a fully closed herd with a high health status and a history of vaccination and anthelmintic treatments.

Our herd are vaccinated against leptospirosis, IBR and salmonella, so matching this status through a planned vaccination protocol on arrival is important.

Other issues of concern are fluke, worms, lice and mange, which might need to be addressed during the isolation period.

Buying a lame animal is a red flag, as the problems associated with digital dermatitis (mortellaro) will remain in the herd for eternity.

TB incidence has been creeping up in the Waterford area over the past two years. Buying from a farm that has a number of years being TB-free is essential, as TB is a slowly developing disease and tuberculin skin testing will pick up only about 80pc of infected animals, .

Transportation is another hurdle. We use our own cattle box rather than a cattle haulier, who might have many animals passing through a box — the best disinfection protocols can’t eliminate the risk.

A minimum four-week quarantine period is necessary but here we found an issue. As this bull had been reared with a group of young bulls for his whole life, the breeder warned us not to leave him on his own. Isolation on a strange farm for a 24-month-old bull would be stressful and could cause unpredictable or dangerous behaviour.

Here my veterinary learnings warred with safe, practical, good advice. The compromise we reached was to put a dry cow due to be culled in April with him on arrival, and it was the right thing to do.

When Bob (as he is now known) arrived on the farm, he had his head suspiciously cocked in the air looking for his friends as he bounced out of the cattle box.

After doing a round or two of the yard I finally managed to coax a 13-year-old cow from her comfortable cubicle to come and join this young buck in the yard. One look from big momma and he instantly calmed down and quietly wandered into a small paddock… if only all problems in life were this simple.

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Gillian O’Sullivan farms with her husband Neil near Dungarvan, Co Waterford