22 March 1996

HOW TO KEEP A CLEAN TEAT

By Jessica Buss

TEAT damage is a sign that teat cup liners, milking machines or teat dipping practices are failing.

This was the message of Ian Ohnstad of ADAS Starcross at a MAFF Milking Machines and Animal Welfare meeting.

When several cases of a specific type of damage are seen on teats after milking, the cause should be investigated.

Mr Ohnstad claimed that poor teat cup liner action could reduce the effectiveness of the teat orifice as a barrier to mastitis. It was vital, therefore, to use the correct type of liners and claw pieces for cows and that vacuum and pulsation levels are correct.

One type of damage is hyperkeratosis. This is caused when dead keratin cells collect at the teat end. These should be flushed away at the next milking but a build-up increases the risk of mastitis.

Tissue congestion at the top of the teat towards the end of milking is a sign that liners are slipping too much or that the cluster is too light, claimed Mr Ohnstad.

Teats that are stiff and cold at the end of milking may indicate that the pulsation is not set correctly. The cow will often knock the cluster off, he added.

Black spot is not directly a milking machine related problem, he said, but will be seen when cows have hyperkeratosis and are then housed in dirty environments.

Chapped teats also allow bugs to hold onto the teats and poor liners can wash these bugs around the teat. Teat chapping is also more common on low level parlours as the units can pull back so the action of the liner is not true and this causes cracking.

He stressed that teat sprays and dips help to cure chapping only when they contain sufficient emollient such as glycerin and lanolin.

"Emollient levels are often better in ready-to-use products but more emollient can be added to concentrates providing it is mixed on a daily basis," he said. "Correct use can then improve teat condition in two weeks."

He believed that the only way to ensure every teat is thoroughly disinfected is to dip, for it is critical to cover the teat end and condition the skin of the whole teat.

He recommends dynamic testing of machines during milking and advises producers have machines tested as well as serviced as recommended by the manufacturer.

Liner choice

Liners must be chosen to match teat length and make of claw piece.

"Makes should not be mixed and matched and when the effective length of liner means it cannot collapse cows get no relief from the vacuum," said Mr Ohnstad.

One example is tapered liners which are designed to creep up the teat so a heavier claw is needed. And, when liners slip the bore may not be wide enough.

He recommended shielded liners to reduce the impact of vacuum on the teat in preference to check-ball type liners, except for herds with long teats. &#42


&#8226 Vacuum regulator.

&#8226 Vacuum gauge.

&#8226 Rubbers and claw piece.

&#8226 Cluster air bleeds.

&#8226 Pulsators.


DAILY MACHINE CHECKS

Check cows teats for signs of damage and chapping after milking.