Effects of breed on foraging sites and diets in dairy cows on mountain pasture

摘要

Biodiverse semi-natural pastures are threatened because of sub-optimal grazing. Breed effects on choice of foraging vegetation type, diet and hence pasture management was investigated in dairy cows kept on mountain pastures. Five dairy cows each fromthe traditional Swedish Mountain breed and the commercial Holstein breed were equipped with GPS receivers measuring animal position for 6 h daily grazing time during 6 days. Plant groups in ingested vegetation were recorded visually for 30 min per cow and day. The grazing area, mapped using infra-red aerial photography combined with field work, consisted of ten vegetation types dominated by bilberry forest (33%), mixed forest (28%) and grass and sedge fen (12%). Although grass-dominated pasture comprised only 0.3% of the area, the cows spent, on average, 27% of their time there. Swedish Mountain cows spent less time in grass-dominated pasture than Holsteins (24% vs. 31%, p = 0.035). Swedish Mountains also travelled longer distances (6.3 vs. 5.0 km, p =0.016) and were scattered over longer distances from other cows (419 vs. 259 m, p = 0.011). This limited study revealed a general selection of grass-dominated pasture, but indicated that using traditional breeds can result in better management of othervegetation types.