Intake, feed conversion efficiency and grazing behaviour of two Holstein cow strains in a pasture-based production system under organic farming in Switzerland

Abstract

Better efficiency of herbage utilisation by dairy cows even under organic condition needs more attention. Therefore, Holstein-Friesian dairy cows of New Zealand (HNZ) and Swiss origin (HCH) were compared in a pasture-based, seasonal calving system on an organic farm. During the 3-year investigation intake on pasture, feed conversion efficiency, grazing behaviour and physical activity of cows were compared. The HNZ were lighter (521 vs. 608 kg, P < 0.001) and showed a higher body condition score (2.9 vs. 2.6, P < 0.001) compared to HCH. Furthermore, the HNZ produced less energy-corrected milk (18.2 vs. 21.3 kg/day/cow, P < 0.001) and had a lower total intake than HCH (14.6 vs. 16.7 kg dry matter (DM)/day/cow, P < 0.001). No differences occurred between strains concerning herbage intake (13.0 vs. 12.8 kg DM/100 kg body weight (BW)0.75/day, P = 0.50) and total intake (13.4 vs. 13.6 kg DM/100 kg BW0.75/day, P = 0.52) relative to the metabolic body weight as well as for the short-term feed conversion efficiency (1.29 vs. 1.34 kg/kg, P = 0.22). Cows of both strains grazed equally long (571 vs. 582 min/day, P = 0.25). The HNZ ruminated longer (507 vs. 474 min day−1, P < 0.001) than HCH. No differences were found between strains regarding the number of rumination boli (577 vs. 556/day, P = 0.34) and of mastications per rumination bolus (60 vs. 59, P = 0.66). Further, no differences occurred concerning physical activity. Pertaining to grazing around dung patches, no differences were observed between strains. Striking differences in grazing behaviour were not observed, except prolonged rumination per day for HNZ, but this had no apparent effect on the feed conversion efficiency.