The effect of rearing conditions during the milk-fed period on milk yield, growth, and maze behaviour of dairy cows during their first lactation.

The objective was to find whether cow growth, milk performance, and behaviour are affected by (1) rearing conditions until weaning after a milk-fed period of 84 d and (2) the sire lineage. Thirty-five Holstein heifers were assigned to one of three treatments: SM, , pen with mother to 21st day, then group pen (they received a maximum of 6 kg of milk daily); SN, , after 3 d with own mother in pen with nursing cow (they received a maximum of 6 kg of milk daily); H, , in hutch from the 2nd to 56th day (6 kg of milk replacer daily), then loose housing pen to weaning (6 kg of milk replacer daily). After weaning at the 84th day, all heifers were kept in pens with the same ration as during calving. During lactation, live body weight (LBW) was measured each month and milk yield each day. Maze learning was evaluated in the fifth month of lactation. The data were analysed using a general linear model ANOVA. At the 30th day, the LBW tended to be the highest in SN (SM 528.2   11.4 kg, SN 571.7   15.3 kg, H 533.2   12.3 kg). When lactation ended, the highest LBW was in SN and the lowest in H (SM 612.6   12.2 kg, SN 623.1   16.4 kg, H 569.8   13.2 kg; ). The SN tended to have the highest production of milk (SM 7143.9   241.5 kg, SN 7345.1   319.0 kg, H 7146.7   234 kg), and the H for FCM (SM 6290.3   203.2 kg, SN 6307.6   268.4 kg, H 6399.3   197.1 kg) for 305 d lactation. Group SN crossed the maze fastest (SM 1141.4   120.5 s, SN 810.3   160.5 s, H 1120.8   118.6 s). The vocalization number differed significantly (SM 32.3   5.7, SN 20.8   4.4, H 9.9   2.6; ). The results indicated that the rearing method up to weaning may have an impact on dairy cows' performance and behaviour.