Metabolic profile and productivity of dairy Holstein cows milked by a pasture-based automatic milking system during early lactation: Effects of cow temperament and parity.

This study aimed to evaluate the influence of temperament and parity on milk production and metabolic responses of Holstein cows in a pasture-based automatic milking system. Thirty-five primiparous and 58 multiparous cows were classified as 'calm', 'intermediate' or 'reactive' in each of the temperament tests conducted: milking reactivity (MR), race time (RT), flight speed, and flight distance. The milk yield and milk composition, as well as the blood biochemistry, were measured during the first 10 weeks of lactation. Primiparous cows produced less milk than multiparous cows (24.0 ± 0.8 vs. 34.2 ± 0.6 L/d, respectively, P ˂ 0.0001), while the serum beta-hydroxybutyrate concentration differences according to parity were not detected. Multiparous cows that were classified as 'reactive' on MR and RT tests produced 3 kg/d more milk and had greater concentrations of milk components than 'calm' cows (P ≤ 0.05). There was no such relation in primiparous cows. Also, cows scored 'reactive' on RT showed greater milking frequency (2.50 ± 0.05 vs. 2.35 ± 0.04 milking/d; P = 0.01) and blood beta-hydroxybutyrate concentrations (1.28 ± 0.09 vs. 0.92 ± 0.10 mmol/L; P = 0.04) than RT 'calm' cows. In conclusion, the cows' temperament was associated with milk production and metabolism, which depended on parity and the temperament tests used. Although productive performance was different between parities, lipomobilization was not.