Once-a-day milking: possible and profitable?

Once-a-day (OAD) milking offers a major opportunity to improve labour output on New Zealand farms. However few full lactation studies have been undertaken to investigate the effect of this strategy on the productivity of the farm system. A trial was established in 2000 to measure the effect of milking frequency and breed in farm systems where stocking rate was adjusted to equalise per hectare feed demand in different herds. There were four treatments: two herds of 35 Friesian and 42 Jersey cows, at 3.5 and 4.2 cows/hectare respectively, were milked OAD for the entire season. Another two herds of 30 Friesian and 36 Jersey cows, at 3.0 and 3.6 cows/ hectare respectively, were milked twice a day. A higher stocking rate was used for the two OAD herds in an attempt to compensate for the effects of the expected decrease in feed eaten. In the Jersey herd, milking OAD resulted in decreased milksolids (MS) yield per cow and per hectare of 22% and 9% respectively. In the Friesians the corresponding decrease was 31% per cow and 19% per hectare. OAD milking resulted in significantly higher protein and milksolids concentrations, and lower lactose concentration. Mean individual somatic cell count was significantly increased by OAD milking, despite the absence of any differences in levels of bacterial infections between herds. The reduction in MS yield per cow and per hectare was smaller for the Jersey herd than the Friesian herd, indicating that the Jersey cow is perhaps better suited to OAD milking.