Effects of short-term once-a-day milking in early lactation on dairy cow performance when managed in a seasonal-calving pasture based system

Abstract

The availability of labour during a compact calving period, can pose a challenge to dairy farmers. The objective of this study was to investigate, in comparison to twice-a-day (TAD) milking, the effect of short-term once-a-day (OAD) milking for four (OAD4), six (OAD6) or eight (OAD8) weeks directly post-calving on milk production, cow health and welfare. After each treatment finished their respective time on OAD milking cows reverted back to TAD milking for the remainder of lactation. A milk yield reduction of 21% was observed after the first four-weeks of lactation when milking OAD compared to TAD (618 kg/cow). When OAD milking continued until week six or eight of lactation milk yield reduction increased to 24 and 26%, respectively, compared to TAD. Following the 35-week lactation OAD6 (4,913 kg/cow) and OAD8 (4,815 kg/cow) treatments had a lower cumulative milk yield compared to the TAD cows (5,300 kg/cow); OAD4 were similar to all treatments (5,073 kg/cow). Following the first four weeks of the experiment the TAD herd had a higher milk fat, protein and lactose yield (+0.29, +0.17 and 0.28 kg/cow/day, respectively) than the three OAD herds which were not significantly different to each other (1.19, 0.72 and 0.95 kg/cow/day, respectively). Total milk fat, protein and lactose yields for the first six weeks of lactation were similar for all OAD treatments (44, 28 and 38 kg/cow, respectively) compared to the TAD treatment (54, 33,and 47 kg/cow, respectively). Following the first eight-weeks of lactation milk fat, protein and lactose yields were highest for the TAD (72, 45 and 65 kg/cow, respectively); OAD6 and OAD 8 were similar, OAD4 was similar to OAD6 but higher than OAD8. There was no difference in kg fat + kg protein (MSY) between treatments at the end of lactation. During the first four weeks of lactation milking cows OAD increased (+ 0.95 units) somatic cell score (SCS) compared to cows being milked TAD (3.26 units). From week five of lactation onwards there was no difference in SCS between any of the treatments. Milking time was consistently less (up to 35% less) when cows were milked OAD compared to TAD. The likelihood of milk leakage from udders pre-milking was significantly higher with OAD compared to TAD milking. There was no effect of treatment on locomotion score or fertility. The results of this study indicate that OAD milking for a short period of time in early lactation may be a viable option to reduce labour requirements without having a negative impact on cow milk production or welfare indicators.