Elsevier

Journal of Dairy Science

Volume 77, Issue 2, February 1994, Pages 426-432
Journal of Dairy Science

Article
Mammary Epithelial Cell Tight Junction Integrity and Mammary Blood Flow During an Extended Milking Interval in Goats

https://doi.org/10.3168/jds.S0022-0302(94)76969-1Get rights and content
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Abstract

The timing and relation of changes in mammary epithelial cell tight junction integrity and mammary blood flow during a 36-h milking interval were studied in six lactating Saanen goats. An increase in lactose concentration in plasma, a decrease in transepithelial potential difference, and changes in ionic milk composition were used to indicate tight junction patency. After 36 h of milk accumulation, mammary tight junctions had become disrupted. Further analyses indicated that this disruption began after 21 h of milk accumulation and that mammary blood flow also started to decline after 21 h. The time when both events occurred was not significantly different from the time when milk secretion began to decline (19 h). Moreover, positive but nonsignificant correlations existed between these events. Mammary tight junctions became disrupted when milk secretion declined, suggesting that impairment of mammary tight junction integrity is associated with decreased milk secretion during an extended milking interval. The decline in mammary blood flow may be the result of a negative feedback response to a reduced demand for metabolites, which is due to a reduced rate of milk secretion.

Key words

goat
milking interval
tight junction
mammary gland

Abbreviation key

FMGC
functional mammary gland capacity
MBF
mammary blood

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