A bit early in the year yet for abortions, I thought, as one of our most progressive dairy farmers called to collect the first dose of salmonella vaccine for his heifers.

This farmer has been expanding his dairy herd for the last 10 years and had an outbreak of salmonella abortions six years ago.

A herd vaccination programme, consisting of annual vaccination in September, seemed to have sorted the problem with only a small setback to the expansion plan.

I then remembered that last year he had forgotten to vaccinate his heifers until one aborted in late September.

Salmonella was quickly identified as the cause but two more heifers had aborted by the time the full vaccination programme had been administered.

A costly oversight, which shows the importance of a herd health plan or at least a vaccination calendar.

The peak time for salmonella abortions is around time of drying off, so it is important to vaccinate prior to the risk period to give maximum herd protection.

Heifers need two doses of vaccine separated by an interval of 21 days, so, in high risk herds or those with a previous history of salmonella abortion, the first dose is due now.

Previously-vaccinated cows need an annual booster, which, in herds with a history of abortion, should be given in September. This farmer had learned the hard way and was not going to make the same mistake twice.

We have seen an increase in salmonella incidence in recent years, particularly in our larger and expanding herds.

In some herds we see abortions, others have sick cows and some have disease in calves. In all infected herds, we use vaccination as a tool to increase herd immunity and reduce shedding of salmonella by infected animals.

Many of the animals remain carriers of the infection, so annual boosters are necessary. The timing of vaccination depends on the type of disease seen on the farm. Of course, the vaccination programme must be combined with other measures, including isolation of sick animals and good on-farm hygiene practices.

With the spotlight on reducing antibiotic usage in future, well-designed vaccination programmes will play a vital role in controlling disease at farm level.

As preventative medicines are now becoming a significant cost on many farms, consulting your vet to decide the optimum programme for your farm would be time well spent.

* Michael O’Meara works at Gortlandroe Vet Clinic, St Conlon’s Rd, Nenagh, Co Tipperary. Gorltandroe Vet Clinic is part of XLVets. XLVets is a group of progressive practices who are working together to achieve a better future for agriculture and veterinary in Ireland. See www.xlvets.ie