GUTWORM is said to cost UK dairy farmers more than £314m a year in reduced milk yields. Merial Animal Health has based its claim on five years of bulk milk tests – known as MOO tests - from 2009 to 2013 involving 790 herds across the UK. The test measures the level of antibodies to gutworm in the milk – to assess the level of challenge to the cows. A “high” result indicates the herd should be treated to remove gutworm.

Victoria Hudson, brand manager for Merial, said: “With margins ever tighter, a drop in milk yield and subsequent reduction in income is a serious threat to dairy farmers.

Numerous studies have shown that gutworm has a damaging effect on milk production.

Treating cows which have been infected with gutworm can increase milk yields by up to 2.6 litres per cow per day – over a 305 day lactation period that really adds up.”

Analysis of the latest figures indicates that on average 88.86 per cent of the UK’s dairy herd are subject to a high gutworm challenge, putting over 1.6m cows at risk from under-performance and costing farmers over £314m in lost profit based on an average farmgate price of 30p per litre.

Wales, Scotland and Northern Ireland fare even worse, with 93.92 per cent of Welsh herds subject to a high challenge and missing out on an additional £41.2m of profit, Scottish herds 96.55 per cent (£34.4m) and Northern Ireland’s herds 100 per cent (£55.9m). In England the figure was slightly lower, with an average of 86.43 per cent of herds affected, with English dairy farmers losing out on an additional £189m.

Ms Hudson said: “Gutworm infection does not usually result in clinical signs such as scouring – so it can be difficult for farmers to know whether cows are infected. MOO tests give an indication of gutworm challenge at a herd level, so farmers can make an informed decision on treatment.

Treating cows with Eprinex (eprinomectin) at housing is an ideal time. The product is fast acting with 88 per cent of cows free from worm eggs three days after treatment.

“Removing gutworm when cows come off pasture means they make the most of expensive winter feed and farmers will reap the rewards of additional milk yield”.