Specific aspects of milk ejection in robotic milking: a review

Milking routines in automatic milking systems (AMS) differ from those in co nventional milking. While milking intervals are constant and teat cups are attached simultaneously in conventional milking, in AMS milking intervals a re variable and attachment of teat cups can be sequentially delayed. Experi ments were performed to test effects of pre-milking teat cleaning, of diffe rent milking intervals in different lactational stages, of delayed teat cup attachment and individual teat cup removal on oxytocin release, milk eject ion and milk removal. Teat cleaning caused oxytocin release and induced mil k ejection. The lag time from start of teat Stimulation until milk ejection occurred increased with decreasing milking interval and was longer in late than in early lactation. In addition, milk fat content increased towards t he end of lactation and was higher after short than after long intervals fr om previous milking. Sequentially delayed attachment of teat cups every 20 s or every 60 s did not reduce oxytocin release. However, total interruptio n of teat stimulation for 2 ruin between pre-stimulation and start of milki ng resulted in transiently decreasing oxytocin concentration and increasing amounts of residual milk. The quarters in which teat cups were last remove d had non-significantly the smallest amounts of stripping and residual milk . The stimulatory effect of single teat cups during sequentially delayed at tachment is sufficient to maintain adequate oxytocin release and maximum mi lk ejection. (C) 2001 Elsevier Science B.V. All rights reserved.