Plant and vegetation preferences for a high and a moderate yielding Norwegian dairy cattle breed grazing semi-natural mountain pastures

Plant and vegetation preferences of two Norwegian cattle breeds grazing semi-natural mountain pastures were studied for two weeks at two farms during one summer. Two rather different grazing sites gave the opportunity to study the two breeds at different pasture qualities, as well as to test if there is any interaction between breeds and study sites. Each of the two herds consisted of the old, moderate yielding Norwegian dairy breed Blacksided Trnder and Nordland Cattle (STN) and the modern, high yielding dairy breed Norwegian Red (NRF). In order to measure the plant preferences of the animals, faeces samples were collected and analysed for plant fragments. In addition, GPS-data showed the terrain chosen by the herds, and vegetation maps were drawn to find the connections between the grazed vegetation and plant preferences. The study shows that on nutrient and especially species rich vegetation growing on base and nutrient rich soil, as at the first study site (Skbu), the plant species, plant genera and plant groups analysed for in the faeces samples indicate that both the STN and NRF breeds graze very much the same vegetation. However, the results from the second study site (Valdres), where the soil is less fertile, the plant species diversity is lower and the plant species distribution less uniform, the moderate yielding NRF breed seems to cover its higher nutritious requirements by grazing in areas with more nutrient rich vegetation compared to the lower yielding breed, STN. grazing preferences / cattle / intensive and extensive breeds / pasture management / seminatural grasslands Rsum -Prfrences en termes de couvert vgtal et d'espces vgtales des races bovines norvgiennes forte production laitire ou modre pturant des prairies d'altitude seminaturelles. Les prfrences alimentaires de deux races bovines norvgiennes pturant des prairies