Variation of Somatic-Cell Counts in Colostrum and Milk of 1St and 2Nd Lactation Cows During 10 Days After Calving

Veterinarni Medicina 39, 1994, 519-532

Samples of mammary gland secretions were collected during the first 10 post partum days from six 1st lactation and six 2nd lactation Holstein-Friesian cows. Mean (+/-SD) somatic cell counts in quarter foremilk samples were 447 (+/-241).10(3)/ml and 620 (+/-246).10(3)/ml in the 1st and 2nd lactation cows, respectively. The difference was significant (P < 0.05). The corresponding values for bucket milk samples were 355 (+/-320).10(3)/ml and 517 (+/-242) 10(3)/ml, respectively. The difference was insignificant (P > 0.05). Mean foremilk somatic cell counts were significantly higher than mean bucket milk counts in both the 1st and the 2nd lactation cows (P < 0.05 and P < 0.01 respectively). A negative correlation between somatic cell counts in both foremilk and bucket milk samples and milk yield was evident in both groups of cows. Somatic cell counts decreased rapidly in bucket milk samples and were lower than 261.10(3)/ml and 192.10(3)/ml in the 1st and the 2nd lactation cows, respectively, on post partum day 10. Values higher than 300.10(3) cells/ml were not found in any of bucket milk samples collected on post partum day 5. Higher counts were found only in foremilk quarter samples collected from 2 glands of 1st lactation and 1 gland of a 2nd lactation cow. None of the mammary glands of any of the cows became infected during the investigation period. Somatic cell counts in non-infected 1st and 2nd lactation cows are apparently time-dependent and cannot be regarded as characteristic features of individual animals

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