Rates of recovery of milk yield and composition following milking intervals of
varying length
V.C. Farr, K. Stelwagen and S.R. Davis
Dairy Science Group, AgResearch, Ruakura Research Centre,
Hamilton
Proceedings of the New Zealand Society of Animal Production. 1998,
58: 47-48
In order to examine the rate of recovery of milk yield and
composition following an extended milking interval, 20 cows were milked
out with the aid of oxytocin and subjected to single intervals of either
16, 24, 32 or 40h. Cows were then milked frequently with the aid of
oxytocin during the subsequent 26h. Milk secretion rate was depressed to
67 and 56% of pre-treatment (twice-daily milking) rates by the 32 and
40h treatments, and rates of recovery were slow, extending beyond 26h
post-treatment. Milk fat and protein contents did not differ
significantly among treatment groups while lactose content was reduced
by the 32 and 40h intervals, recovering by 26h post-treatment. It was
concluded that the udder is particularly sensitive to milk accumulation
beyond 24h and that this leads to impairment of the ‘synthetic
machinery’ in the udder. The prolonged effect on milk lactose
concentrations with the longer intervals suggests that there was a
sustained change in the integrity of tight junctions between secretory
cells, leading to increased permeability of the mammary gland. Rates of
recovery of yield and composition were relatively slow, taking >24h in
spite of enhanced rates of milk removal.
Keywords: NZSAPAB;
Milking interval, once-daily milking, milk yield, milk lactose
Last Updated 12-09-1998
