Studies of grazing behaviour in relation to grassland management I. Variations in grazing habits of dairy cattle

摘要: 1. A series of grazing behaviour observations on 10 sets lactating identical twins is described. Four fortnights distributed over the main lactation period were covered. In three fortnights, made six 24 hr. periods, while in remaining fortnight cows observed all 14 days. 2. Anoutstanding feature dairy cattle its variability, due to external and internal conditions. 3. Of factors, climate (in a temperate zone) relatively unimportant. 4. The quantity quality herbage offered are importance modifying cattle. Under adverse pasture conditions there is, general, an increase total working time (grazing + ruminating): increases with scarcity mixed quality, ruminating prolonged by poor grass. 5. Ruminating strongly dependent ingested grass, but relationship for various reasons, obscured field trial such as present. 6. adaptation habits new very rapid. 7. Feed requirement milk production most important factor determining variation length time. 8. Inheritance × environment interactions source variations times following factors: ( ) Differences amongst twin lactational persistency, which presumably cause parallel differences feed requirements. b response high low producing varying c Non-analysable idiosyncrasies common members some sets. 9. Twin graze ruminate at characteristic rate.