Peripartum Changes of Plasma and Milk Vitamin A and β-Carotene among Dairy Cows with or without Mastitis

Abstract

Over 12 mo we studied the relationship between peripartum concentrations of vitamin A and β-carotene in blood plasma and milk of 93 Holsteins with or without subsequent mastitis. Blood was sampled daily from 7 days prepartum through 7 days postpartum and on alternate weeks through wk 10 of lactation. Milk samples were collected daily for 7 days postpartum and then biweekly for 10 wk. Somatic cell counts were on biweekly milk samples. Vitamin A and β-carotene of blood plasma decreased rapidly prepartum to reach minimum concentrations at calving (vitamin A) or on day 4 to 6 postpartum (β-carotene). Thereafter, both vitamin A and β-carotene increased rapidly through 10 wk postpartum. Concentrations of vitamin A and β-carotene in colostrum were higher than concentrations in milk. Cows with mastitis (somatic cells >5 00,000 cells/ml milk) had lower vitamin A in blood plasma during days 0 to 7 and wk 2 and 4 postpartum than cows without mastitis. When data were analyzed with loge of somatic cell count as an independent regression variable, results were similar. In contrast to vitamin A, peripartum β-carotene in blood plasma was higher among mastitic cows and was related to higher loge of somatic cell count. No significant difference was observed between mastitic and non-mastitic cows for vitamin A and β-carotene in milk. Lower concentrations of plasma vitamin A and higher concentrations of β-carotene during the immediate postpartum period were associated with higher milk somatic cell counts among dairy cows during lactation. © 1984, American Dairy Science Association. All rights reserved.