Concentration of plasma and milk vitamin E and plasma beta-carotene of mastitic and healthy cows.

Variation of vitamin E in blood plasma and milk and beta-carotene in blood plasma of 38 healthy and 38 mastitic cows was studied. Cows were assigned to one of the two treatment groups: control and vitamin E supplemented. Vitamin E supplementation was started when cows were dried-off at the end of lactation and continued until 3 months post partum at the rate of 1000 IU per cow daily and then reduced to 500 IU for the remaining lactation. A cow was considered mastitic when somatic cell count of milk was greater than 500 x 10(3) cells/ml. Milk samples with somatic cell counts below 100 x 10(3) cells/ml were from healthy cows. Data on vitamin E concentration of plasma and milk and beta-carotene in plasma were analyzed by a least squares procedure. The model included the effects of treatment, mastitis status, stage of lactation, and all first order interactions. Mean vitamin E levels in plasma and milk of supplemented cows were significantly higher than of the non-supplemented cows. Plasma and milk levels of vitamin E as well as beta-carotene in plasma were significantly lower in mastitic than healthy cows. When data were analyzed with loge, of somatic cell count in milk as an independent regression variable, results were similar. There was a negative correlation of mastitis status with vitamin E levels in plasma (-0.48), milk (-0.24), and beta-carotene in plasma (-0.38).(ABSTRACT TRUNCATED AT 250 WORDS)