Abstract

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.

HI, Kamote, CW Holmes, DDS MacKenzie, RJ Holdaway, and BW Wickham

Proceedings of the New Zealand Society of Animal Production, Volume 54, , 285-288, 1994