Effects of once daily milking in late lactation on cows with either
low or high initial somatic cell counts.
H.I. Kamote, C.W. Holmes, D.D.S. Mackenzie, R.J. Holdaway, B.W.
Wickham.
Department of Animal Science, Massey University, Palmerston North,
New Zealand.
Proceedings of the New Zealand Society of Animal Production 1994,
54: 285-288
The present study was carried out in order to measure the effects of
once daily milking on somatic cell count (SCC) of cows which had either low
SCS
or high SCC at the start of the experiment in late lactation. Thirty six cows
were used, 18 with low SCC and 18 with higher SCC. Nine cows from each
group were randomly allocated to once or twice daily milking for the four week
experimental period in March. The yields of milk, fat, protein and lactose were
significantly reduced by once daily milking (P<0.01) in both groups. However,
the effects of once daily milking on yields was larger for high SCC cows
(interaction P<0.01). Once daily milking significantly increased the
concentration of protein (P<0.001) in both groups and fat (P<0.01) in only the
low SCC group. Once daily milking significantly reduced the concentration of
lactose, the effect being larger in the high SCC group (interaction P<0.001).
SCC (per ml) was increased by once daily milking, but the effect was
significant only in the high SCC group (interaction P<0.10). The total number
of cells produced per day were not affected by once daily milking.
These results show that SCC can be used with confidence to identify
subclinically infected cows in later lactation milked once or twice a day. The
results also show that cows with a low incidence of subclinical mastitis can be
milked once daily in later lactation, with much less effect on yield of milk and
its constituents than would be expected in cows with a higher incidence of
infection.
Keywords: NZSAPAB;
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Last Updated 25-01-1997
