Characterisation of productive performance, body reserve dynamics and energy metabolic parameters of Holstein Friesian and Normande dairy cows managed in a low-input pastoral dairy system

Abstract

Context Dairy cows with autumn-calving season in low-input pastoral systems are subjected to challenging conditions as their early lactation falls in autumn and winter when shortages in pasture availability and harsh weather conditions often occur. Aims We aimed to assess the associations between breed (Holstein Friesian (HF) vs Normande (NR)) and stage of lactation on productive and metabolic responses over lactation in a low-input pastoral dairy system. Methods Twenty-seven HF (n = 14) and NR (n = 13) cows were studied. Milk yield was measured fortnightly, and milk composition, milk solid yield, liveweight (LW), body condition score (BCS) and blood plasma energy metabolites were assessed monthly. Key results The greater milk for HF versus NR cows (e.g. 17.4 vs 12.1 ± 1.0 kg/day of milk; P < 0.001) were associated with a lower LW (510 vs 540 ± 10 kg; P = 0.021) and BCS (1.84 vs 2.37 ± 0.10; P = 0.001) at nadir for HF than NR cows. Blood plasma concentrations of non-esterified fatty acids (NEFA) were high for longer in HF versus NR cows (18 vs 8 WRC). Plasma glucose was greater (P = 0.002) and insulin was lower (P = 0.021) for HF versus NR cows at 3 WRC. During mid-lactation, glucose (22 WRC, P = 0.021) and insulin (26 to 34 WRC, P ≤ 0.041) were lower for HF vs. NR cows. Conclusions Because of their lower milk yields, NR cows had a shorter period of body reserves mobilisation, which was associated with an earlier decrease of plasma concentrations of NEFA and greater insulin concentrations at 3 WRC, and then again during mid-lactation when LW and BCS were also greater for NR cows. Implications In constraining pastoral environments, NR cows would redirect fewer nutrients for milk synthesis, leading to lower depletion of body reserves, which could be associated with a better ability to cope with winter challenging conditions. Although HF cows had a greater depletion of body reserves, there was no increase in the incidence of health problems for these cows.