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Mastitis in a flock of milking sheep

1996; Elsevier BV; Volume: 22; Issue: 2 Linguagem: Inglês

10.1016/s0921-4488(96)00881-4

1879-0941

John H. Kirk, John S. Glenn, John Maas,

Genetic and phenotypic traits in livestock

Milk samples were aseptically collected from 62 ewes at lambing from a flock of about 400 machine-milked Dorset and Polypay sheep. Of these, 24 ewes were sampled again at weaning upon entry into the milking group. An additional 18 ewes with clinical mastitis were sampled during lactation. Somatic cell counting was done on the milk from 59 ewes in the milking group. At lambing, milk from 29% of the ewes tested was culture-positive. Unilateral infections predominated. Coagulase-negative staphylococci (CNS) were found in 88% of the samples. Of the ewes sampled at both lambing and weaning, 33% were free of intramammary infections (IMI), 38% developed IMI during this period, 21% had spontaneous cures, and 8% had CNS IMI at lambing but were infected with coagulase-positive staphylococci (CPS) at weaning. Of the milking ewes with clinical mastitis, CPS were isolated in 66% of the milk samples while 22% had no growth. Nearly 90% of the milk samples had somatic cell counts of under 200 000 cells ml−1. The reason for the high incidence of CPS clinical mastitis in the milking group was not determined. Somatic cell counts in this milking flock of sheep were similar in magnitude to those found in non-mastitic dairy cows but lower than those for milking goats. This suggests that somatic cell count standards for cow milk could probably be applied to sheep milk. The somatic cell counts indicated a low level of IMI in this milking flock, reflective of the preventive mastitis measures used.