23 June 1995

Pour-on protection &a move indoors does the trick…

It pays to control summer mastitis, as two Cheshire producers have discovered. Jessica Buss reports

SUMMER mastitis has been eliminated on one Cheshire dairy farm after a change in summer management of in-calf heifers.

Lord Tollemaches 445ha (1100-acre) dairy and arable unit, Peckforton Home Farm, Beeston, Tarporley, rears 70 to 80 Holstein Friesian heifers a year as replacements for its 300-cow dairy herd.

For 20 years the farm has been troubled with summer mastitis in heifers, and occasionally dry cows, during July and August.

Heifer rearer Tony Thexton has tried a number of summer fly control measures. Fly tags, placed in each ear of the animal, needed a large group of heifers to spread the protection to the udder. Knapsack spraying worked well, but had to be done frequently. However, the spray he used is no longer licensed. Painting stockholm tar on udders twice a week reduced incidence but was not totally effective and was labour intensive, he claims.

"Cheshire has many trees, particularly on the Peckforton Hills, and a high concentration of cattle, both of which encourage flies and so there are more carrying the mastitis causing bug," he says.

Three years ago, as many as 10% of the heifers were diagnosed and treated for summer mastitis.

"You felt helpless and frustrated that there was no solution," says farm manager Geoff Vickers.

"When youve reared a £1200 heifer it is a shame to lose a quarter to summer mastitis," he adds.

To safeguard that investment, management of the September to November calving heifers was changed two years ago on the advice of Nantwich-based vet Neil Howie of Wilson McWilliam and Partners.

"Summer mastitis (August Bag), can occur in heifers, dry cows and occasionally steers, and is difficult to treat effectively," says Mr Howie. "Once infected milking animals can achieve only 90% of their potential yield.

"In heifers starting to develop their udders, all the investment has been made. 100% successful treatment is rare so summer mastitis prevention is vital."

Heifers at Peckforton Home Farm are now treated with a pour-on liquid, which costs 70p a dose. It is applied every four weeks from early July. Mr Thexton finds it is necessary to treat twice as often as the makers recommended to offer sufficient cover.

The pour-on repellant is absorbed into the animals skin and sweated out, so protection is said to cover the whole animal.

In mid-July when risk of infection from flies is greatest, the in-calf heifers are taken from their summer grazing into a well ventilated straw yard with an outside concrete area.

This has eliminated summer mastitis completely.

"Even if we save only one heifer from risk, the cost is well justified and you can sleep at night knowing they are safe," says Mr Vickers.

The move indoors means there is no need to apply the pour-on again saving the cost of treatment.

"The other benefit of housing the heifers is that they get used to the concrete yard, which is the best way of reducing lameness after calving," says Mr Howie. With fewer flies about there is less New Forest eye, also a problem in the area.

Early housing also gives better control of the pre-calving diet and heifer condition, he claims.

Last summer the 46 September to November calving heifers were fed grass silage and straw with no concentrates.

Mr Howie warns summer mastitis is difficult to treat and that ideally the infected quarter must be stripped out five or six times a day, and the animal injected with antibiotics and anti-inflammatory drugs," he says.

But left untreated summer mastitis is a killer and heavily pregnant animals may abort, he warns. Animals which loose quarters as heifers or in the dry period may have had summer mastitis, even though symptoms are not diagnosed, adds Mr Howie.