Effect of temporary once-daily milking in early lactation on milk production and nutritional status of dairy cows

The effect of temporary once-daily milking, starting right after calving, on milk production and nutritional status of 50 Holstein cows (15 primiparous) was studied. Primiparous cows were divided into two groups: a control group (Pc) continuously milked twice daily and an experimental group (P3) milked once a day for the first three weeks of lactation and then twice daily. Multiparous cows were divided into three groups: a control group (Mc) continuously milked twice daily, an experimental group milked once a day for the first three weeks of lactation and then twice daily (group M3), and another experimental group milked once a day for the first six weeks after calving and then twice daily (group M6). The trial ended when the cows were turned out to pasture. Cows milked once daily did not seem to suffer from discomfort. Once-daily milking decreased the milk yield by 2.7 kg.d(-1) (P < 0.10) in week 1 of lactation, by 8.4 kg.d(-1) (P < 0.01) in week 3 and by 14.5 kg.d(-1) (P < 0.01) in week 6. The effect of once-daily milking was not different between primiparous and multiparous cows. During the first week of twice-daily milking, the milk yield of experimental groups increased by 6.8 kg.d(-1) (a non significant difference between P3, M3 and M6 groups). From week 7 onwards, the milk yield of the P3 and M3 groups was lower than the milk yield of the Pc and Mc groups by 2.4 kg.d(-1) (P < 0.10), and the milk yield of the M6 group was lower than the milk yield of the Mc group by 5.4 kg.d(-1)(P < 0.01). The protein content of milk was higher in experimental groups than in control groups by 2.4 g.kg(-1) during both experimental and post-experimental periods. Somatic cell counts in milk were not significantly different between the groups. Cows milked once a day lost less body condition and live weight in early lactation than control cows, and their energy balance was less negative or more positive (the difference was significant for the M6 group). The blood profile (glucose, non-esterified fatty acids, beta-hydroxybutyrate contents in plasma) attested for a better energy balance in cows milked once a day in early lactation. This trial suggests that high producing cows tolerate to be milked once a day during early lactation and that, through this management, it could be envisaged to feed high producing cows with diets poorer in concentrates than what is currently given today, without impairing health. ((C) Elsevier / Inra).