Abstract

Closed teats have proven more resistant to dry period mastitis than open teats. Natural rate of keratin plug formation within closed and open teats, and consequences of bacterial colonisation of the teat canal, were examined using 67 low somatic cell count cows. Cows were dried off without antibiotic therapy and teats assessed for closure status at 5, 10, 15 and 20 d after drying off. Weight and bacteriological status of the keratin plug was determined by reaming teats with a sterile pre-weighed tapestry needle 7 d prior to drying off and on one occasion post drying off. Initially (d 5), keratin weight for all teats increased by 100% compared to lactating teats (4.89 mg/qtr). Between d 10-20, keratin weight from open teats (29% of teats) was 34-55% less than for closed teats. Subclinical infections in the teat canal significantly reduced likelihood of teats closing after drying off.

SJ, Lacy-Hulbert, JH Williamson, AM Day, and MW Woolford

Proceedings of the New Zealand Society of Animal Production, Volume 59, , 198-200, 1999