22 October 1999

Dry cow cares crucial

MANAGING mastitis infection in dry cows is not just about tubing.

In fact, dry cow tubes are of limited value for controlling environmental mastitis, which requires high quality housing to keep bugs at bay.

Larry Smith of Ohio State University, USA, told delegates that correct dry cow management was critical to mastitis control.

"Many infections present in early lactation and much clinical mastitis occurring at calving and in the first 90-120 days of lactation are due to infections introduced during the dry period. High cell counts during early lactation are also often due to dry period infections."

Prof Smith believes that because problems only become apparent in lactation it is easy to overlook the importance of the dry period in mastitis control programmes.

He advised abrupt drying off, complete milking out at the last milking and cleaning teat ends with cotton swabs soaked in alcohol. Dry cow therapy is also a must.

"Dry cow therapy reduces the reservoir of contagious mastitis bacteria in herds, helping to reduce infection." Prof Smith recommends only partially inserting tubes to avoid damaging teat canals.

Housing dry cows in clean, dry and well-ventilated accommodation, rather than in sub-standard, dirty areas is essential to minimise exposure to environmental mastitis bugs in dung, said Prof Smith. Washed sand is the ideal bedding material, as it does not support bacterial growth, he added.

Poor dry cow nutrition can also make cows more susceptible to disease. "Poor quality forages, low in vitamin E are often fed to dry cows. Vitamin E and selenium are necessary for good immunity.

"Dry cows should receive 1000 iu of vitamin E supplementation a day and about 6-7mg of selenium a day. But cows on high quality pasture or fed fresh, green forages are unlikely to benefit from vitamin E supplementation." &#42