22 March 1996


Dramatic decreases in somatic cell count can be achieved very quickly, given the determination and a co-ordinated approach. Jessica Buss reports how a dairy farm has reduced the count by two-thirds in a few months

ONE Herts-based dairy farm has reduced its average somatic cell count from 800,000 to 250,000 cells/ml in less than one year.

This was due to effective culling and adherence to the five-point plan for mastitis control, claims farm vet John Fishwick of the Royal Veterinary College, Herts.

Mr Fishwick says that with 1m litres of quota for the 170-cow herd, the high cell count had lost the farm £10,000 a year in milk sales. In addition, clinical cases were high, with about 70 in one year. "The target for clinical cases should be 30 a year," he says.

Mr Fishwick had identified infected quarters of cows in the herd treated them aggressively. All the quarters of all cows in milk were tested initially using the California milk test. Milk samples from quarters showing a positive reaction were tested for bacteria present at the local Vet Investigation Centre. A total of 122 milk samples were taken from 140 cows in milk (see table).

"Blitz therapy by treating infected quarters with antibiotic was tried on 60 cows in all four quarters at two consecutive milkings. "But this failed to decrease bulk cell counts," he said. The treatment only reduced cell counts of cows with S agalactiae infection.

As the quota leasing price was high, the farmer decided to lease out his quota and cull 51 cows. Culling cows that had high cell counts or repeated cases of mastitis proved successful in reducing bulk cell counts, and they have continued to decrease, claims Mr Fishwick.

Taking milk samples during milking also gave Mr Fishwick the chance to examine the milking routine. He discovered that the herdsmans milking routine and identification of clinical mastitis was poor.

"No cow was fore-milked, many were wiped with the same paper towel before it was thrown away, and an udder-cloth that sat in a bucket of disinfectant was used on several of the cows," he says. "He also failed to check in-line mastitis detectors, and the post-milking disinfectant spray was applied badly."

The herdsmans milking routine was difficult to improve without his co-operation and good communication between the farm owner, the herdsman, and the farm vet he claims. &#42

Bacteria tests(samples positive)

&#8226 S agalactiae33

&#8226 S dysgalactiae3

&#8226 S uberis24

&#8226 S aureus26

&#8226 C bovis44

&#8226 E coli1

&#8226 No significant bacteria23

To make a serious impact on somatic cell counts, antibiotics are not enough. Rigorous culling, top-notch equipment, and above all, improved milking routines are vital. Farm owner, herdsman and vet all have a part to play. But it can be done.