Influence of milking and restricted suckling regimes on milk production and calf growth in temperate and tropical environments

Two experiments were carried out to investigate the effect of restricted su ckling and milking regimes on milk yield, milk composition and calf growth. Experiment 2 was carried out in temperate conditions in the United Kingdom and experiment 2 under tropical conditions in Mexico. In experiment 2 a La tin rectangle (change-over) design with 3-week periods was used with eight Holstein Friesian cows suckling their Simmental-sired calves. Saleable milk yield (SMY), sucked milk (CSM), milk composition and calf performance were studied. The treatments were: once a day milking (a.m.) with suckling imme diately after (1xAM); once a day milking (a.m.) with suckling p.m. (1xPM); twice daily milking with suckling after a.m. milking (2xAM); twice daily mi lking with suckling after each milking (2x2x). The cows were offered maize silage ad libitum and 4.3 kg dry matter (DM) per day of rapeseed meal plus minerals and vitamins. The calves had ad libitum access to concentrates (16 5 g crude protein (CP) per kg DM) and wheat straw. In experiment 2, 11 B. i ndicus x B. taurus cows, suckling their Brahmansired calves were used in an experiment with the same treatments and experimental design. Cows were off ered star grass (Cynodon nlemfuensis) hay ad libitum and 4.0 kg DM per day of concentrate (117 g CP per kg DM). The calves had ad libitum access to co ncentrate (151 g CP/kg DM), star grass hay and Ramon leaves. For 1xAM, 1xPM , 2xAM and 2x2x respectively in experiment 1, the total milk yields (TMY = SMY + CSM) were 17.9, 18.0, 16.7 and 19.5 kg/day (s.e.d. 1.11) and SMY repr esented 0.70, 0.45, 0.77 and 0.53 of TMY. Corresponding results for experim ent 2 were 6.0, 6.2, 7.0 and 7.1 kg/day (s.e.d. 0.32) and 0.69, 0.45, 0.78 and 0.61. Effects of treatment on milk yield and composition were consisten t with the feedback inhibitor of lactation theory. It was concluded that di fferent milking and restricted suckling patterns can be used to manipulate saleable milk production and calf growth. Holstein Friesian dairy cattle in a restricted suckling system without the calf presence at milking, behaved similarly to zebu-crossbred cows by reducing milk let dozen at milking.