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Research article2019Peer reviewedOpen access

The effect of 17 beta-estradiol on lactose in plasma and urine in dairy cows in late lactation

Agenas, Sigrid; Lundstrom, Idamaria; Holtenius, Kjell


The aim of this study was to investigate the effect of 17 beta-estradiol on mammary tight junctions in cows in late lactation. The experiment included five non-pregnant cows around day 290 in lactation. The cows received injections of 17 beta-estradiol for six days. The effect of exogenous 17 beta-estradiol on milk yield, milk composition and lactose in plasma and lactose in urine was investigated before, during and after the treatment. Milk yield decreased after 17 beta-estradiol injections and lactose in plasma and urine increased, showing an effect on the integrity of the mammary tight junctions. However, there was a delay between hormone injections and the decrease in milk yield and opening of tight junctions, indicating that other factors are involved. A high correlation between lactose in urine and blood plasma was found. More than 30% of the total lactose production was lost in urine after 17 beta-estradiol treatment.


Blood; milk barrier; lactation; mammary tight junction; pregnancy

Published in

Journal of Dairy Research
2019, Volume: 86, number: 2, article number: PII S0022029919000281Publisher: CAMBRIDGE UNIV PRESS