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, o n milk production and nutritional status of 50 Holstein cows (15 primiparou s) was studied. Primiparous cows were divided into two groups: a control gr oup (Pc) continuously milked twice daily and an experimental group (P3) mil ked 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) cont inuously milked twice daily, an experimental group milked once a day for th e first three weeks of lactation and then twice daily (group M3), and anoth er experimental group milked once a day for the first six weeks after calvi ng and then twice daily (group M6). The trial ended when the cows were turn ed out to pasture. Cows milked once daily did not seem to suffer from disco mfort. Once-daily milking decreased the milk yield by 2.7 kg.d(-1) (P < 0.1 0) 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 di fferent 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 significan tly different between the groups. Cows milked once a day lost less body con dition and live weight in early lactation than control cows, and their ener gy balance was less negative or more positive (the difference was significa nt for the M6 group). The blood profile (glucose, non-esterified fatty acid s, beta-hydroxybutyrate contents in plasma) attested for a better energy ba lance in cows milked once a day in early lactation. This trial suggests tha t high producing cows tolerate to be milked once a day during early lactati on and that, through this management, it could be envisaged to feed high pr oducing cows with diets poorer in concentrates than what is currently given today, without impairing health. ((C) Elsevier / Inra).