Keep your eye on gutworm levels

Gutworm challenge could be compromising your herd’s performance, according to Welsh dairy producer Maurice Jones, who has three dairy units milking about 1000 cows in Welshpool.

“It’s paramount to keep animals in peak health if you are to achieve best yields. Our herd averages more than 10,000 litres on twice-a-day milking, and to get them to do that, everything has to be running smoothly,” he says.

However, three years ago, Mr Jones identified some health problems in his cows – including coughing – and consequently conducted a MOO test to help investigate any possible contribution from gutworms.

MOO tests were implemented across the UK throughout 2009 by Merial Animal Health. These tests were carried out on bulk milk samples from 464 farms and were used to identify the level of gutworm challenge facing each herd by measuring milk antibody levels.

For Mr Jones, results showed the farm had an issue with gutworm. As a result he decided to treat all cattle in the autumn.


“The cattle responded to treatment with an overall improvement in productivity. The health problems were resolved and treating with a pour-on has now become part of our routine,” he says.

“We treat the cows about a fortnight after they are housed for winter and have noticed cows are fitter and their coats are nicer. Also milk production has been better. Based on our experience, I would certainly recommend routine annual worming.”

National gutworm levels

Last year Merial Animal Health released national results for the MOO test and identified that 93% of farms sampled were affected by a high level of gutworm challenge. A further 5% faced a medium level of challenge.

Past research has proven gutworm challenge can significantly reduce milk yield by up to two litres a cow a day. Scaled up across the UK national herd, this would equate to £281m a year of recoverable milk losses.

Since addressing gutworm problems, Mr Jones is not only achieving high yields, but he also notes they have many cows now achieving seven or eight lactations. “My own belief is the ones that last are the cows that pay the bills. It is worth the trouble to get those cows in calf, because it costs a lot less to keep them than to rear a heifer.”

Merial vet adviser, Fiona MacGillivray, says many dairy farmers don’t believe gutworm burdens are a problem, as they cause no obvious clinical effects in the adult cow. “However, there is an abundance of independent research which clearly shows worming cows with eprinomectin improves both milk production and fertility.”

The benefits of treatment

“Any dairy farmer who really believes he has one of the few herds which is not facing a significant gutworm challenge and would not benefit from worming his herd should consider trying the MOO test for themselves. They may have a very real and easy opportunity to increase productivity and profitability.”

Ms MacGillivray also believes worming dairy cows and heifers when calving down, while at grass, can be beneficial, as well as during housing. “Most farmers recognise the housing period provides an ideal opportunity to administer a number of treatments, but parasite control is just as important while animals are at grass.”

Maximising feed intake in newly-calved cows is essential to try to minimise the impact of the “energy gap” which occurs as a result of the increased energy demands for milk production for a number of weeks following calving.

By increasing the dry matter intake at this critical time, the energy gap can be effectively managed so body condition changes are minimised, thus improving fertility and increasing milk production throughout that entire lactation.

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