Effect of superimposed pregnancy on milk composition and progesterone level

ABSTRACT

Milk composition and progesterone level were studied in 18 cows at various stages of lactation. Progesterone was below 2 ng/ml in non-pregnant cows, rose steadily to 20 ng/ml on 17th day after insemination which was maintained during pregnancy. In non fertilized cows this level dropped rapidly to basal level. The fats and protein contents were also increased gradually during lactation showing relationship with the milk progesterone level. Lactose level was found constant throughout lactation