Effect of suckling ('restricted suckling') on dairy cows' udder health and milk let-down and their calves' weight gain, feed intake and behaviour

The aim of this study was to evaluate the effects of restricted suckling (RS) in Holstein cattle on the weight gain, health and behaviour of calves and on udder health and milk let-down in cows compared to artificial rearing (AR). The study was conducted in Mexico. The 27 cows with calves were assigned to one of the two treatments and studied until weaning 8 weeks postpartum. Cows were milked three times daily. RS calves were allowed to suckle for 30 min 2 h after morning and afternoon milking, whereas AR calves were fed milk from buckets through a floating nipple at the same time. During suckling/milk feeding, the AR calves performed more oral behaviours such as 'cross-suck' and 'lick object' than RS calves. The RS calves spent a longer time suckling on the front teats than the rear teats. During observations of general behaviour when calves were not milk fed, AR calves displayed more often 'cross-suck', 'lick object', 'eat concentrate', 'eat hay' and 'ruminate' than RS calves. Milk consumption (286 kg) over 8 weeks in both groups and live weight gain (LWG) were similar in RS (26.2 +/- 3.9 kg) and AR calves (26.1 +/- 1.4 kg), but the individual variation in LWG was higher in RS calves. The milk suckled by RS calves contained more fat and metabolisable energy (ME) per kg than the parlour milk fed to AR calves (6.1% vs. 4.2% and 3.5 MJ/kg vs. 2.9 MJ/kg) whereas AR calves ingested more than fourfold as much concentrate as RS calves (21.6 kg vs. 4.8 kg), which resulted in similar total ME intake in treatments. The California Mastitis Test scores revealed a tendency to improved udder health in RS cows compared to AR cows. The average time to milk let-down was similar in treatments. In conclusion, the RS system with the Holstein dairy cattle reduced 'cross-sucking' and 'licking objects' in the calves and tended to improve udder health in the cows, compared to the AR system. (c) 2007 Elsevier B.V. All rights reserved.