Effects of habituation to the milking parlour on the milk production and reproductive performance of first calving HolsteinFriesian and Norwegian dairy herd replacements

Twenty-nine Holstein-Friesian and 20 Norwegian dairy herd replacements were used to investigate the effect of habituating heifers to the milking parlour environment prior to calving on subsequent lactational performance. The heifers commenced the study at 3 weeks prior to calving when they were allocated on the basis of breed, genetic merit and live weight to either a habituation or no habituation (control) treatment. Heifers were housed together in cubicle accommodation with grass silage offered ad libitum along with 1 kg of concentrates per head per day offered in the feeding passage (control treatment) or in the food managers in the milking parlour (habituation treatment). Animals in the habituation treatment were exposed to the full milking parlour routine once daily (afternoon milking) in a 20-point rotary herringbone parlour. Holstein-Friesian heifers averaged 2·6 kg/day more milk than the Norwegian replacements. Holstein-Friesian heifers also had higher fat and protein yields than Norwegian heifers, however they also lost more body condition during the first 3 months of lactation. Habituated heifers yielded on average 1·3 kg/day more milk (P < 0·001) than the control group of heifers over the first 100 days of lactation (26·7 v. 25·4 (s.e.d. 0·38) kg/day), with the difference being greatest in the first 2 to 3 weeks of lactation. In early lactation, animals on the habituation treatment lost more live weight (0·16 v. 0·02 (s.e.d. 0·061) kg/day) (P < 0·05) and body condition than those on the control treatment. Duration of milking was longer (P < 0·001) (378·4 v. 340·5 (s.e.d. 6·53) s) and milk flow rate slower (P < 0·001) (2·20 v. 2·46 (s.e.d. 0·041) kg/min) respectively for the habituation compared with control group. Somatic cell counts (SCC) were lower (P < 0·001) for habituation group (1·66 v. 1·79 (s.e.d. 0·037) log10 SCC per ml), but there was no significant treatment effect on locomotion scores. Reproductive performance was lower for habituated heifers, with increased intervals to conception (P < 0·05) (102 v. 83 (s.e.d. 9·22) days). Habituating heifers to the milking parlour environment prior to calving increased milk production but appeared to have some detrimental effects on reproductive performance.