6Jensen M B,Pedersen L J,Munksgaard L.The effect of reward duration on demand functions for rest in dairy heifers and lying requirements as measured by demand functions[J].Applied Animal Behaviour Science,2005,90(3):207-217.
7Karakok S G,Uslucan B,Tapki I,et al.The effect of straw bedding usage in loose housing systems on behavior and milk production of holstein dairy cows[J].Journal of Animal and Veterinary Advances,2009,8(9):1 824-1 828.
8Drissler M,Gaworski M,Tucker C B,et al.Freestall maintenance:effects on lying behavior of dairy cattle[J].Journal of Dairy Science,2005,88(7):2 381-2 387.
10Telezhenko E,Lidfors L,Bergsten C.Dairy cow preferences for soft or hard flooring when standing or walking[J].Journal of Dairy Science,2007,90(8):3 716-3 724.
