Short and long-term effects on the teat tissue in a Cow Calf Contact system with automatic milking

Abstract: The interest in keeping calves with their lactating dams in dairy production is increasing, among both dairy farmers and consumers. This MSc thesis is a part of an ongoing project at the Swedish University of Agriculture (SLU) where a cow-calf contact system with automatic milking is studied. One of the concerns of integrating calves in dairy production has been that the udder health might be impaired, and that the combination of milking and suckling involves a high strain on the teats. Teat end callosity (TEC) is a long-term effect of wearing of the teat caused by machine milking. The swelling of the teat wall during machine milking is a short-term effect on the teat tissue, also caused by machine milking. Both TEC and increased teat wall thickness (TWT) during machine milking might be risk factors for impaired udder health. The purpose of this thesis was to examine differences in TEC and TWT between nursing dairy cows (treatment) and control cows. The cow-calf project at SLU is divided into several batches. The present study included batch 1 and 2, with a total of 30 treatment cows and 26 control cows housed in a loose house system. Calves had free access to their dams in a contact area and cows were milked in an automatic milking system (DeLaval VMS™ Classic). Calves and cows were separated approximately 16 weeks postpartum. The scoring of TEC was performed according to the scheme developed by Neijenhuis et al. (2000). TEC was scored at four occasions: prior to parturition, about eight weeks postpartum, prior to separation and eight weeks after separation. Any wounds on the teats were noted at each scoring event. TWT was assessed pre- and post-milking by ultrasound about 11 weeks postpartum. 180 images of 90 teats was used for further statistical analysis. Treatment cows had significantly (p < 0.05) lower mean TEC scores post-partum in batch 1 compared to control cows. There were no significant differences in mean TEC score between treatment cows and control cows at the other scoring events. In batch 2 there were no significant differences in mean TEC score between treatment cows and control cows. A total of nine wounds was noted during the whole study period. There was a significant increase (p < 0.001) in TWT during milking in both groups, yet, there were no significant difference in TWT increase between treatment cows and control cows. This study found no evidence that the degree of TEC, the number of wounds, or the TWT were negatively affected by suckling calves in this automatic milking system.