Are physical and feeding activities at pasture impacted by cattle breed and feeding restriction?
Résumé
Recording locomotion and feeding activities coupled with animal performances could contribute to characterize the adaptive responses of animals subjected to disturbances. In this study physical and feeding activities at pasture of 16 suckling cows subjected to a previous indoor feed restriction have been characterized. The experimental design combined 2 breeds (Charolais, CH and Salers, SA) and 2 indoor feeding levels (Control, C: 120% of requirements and Restricted, R: 70% of requirements) from calving to turnout (110 days). Physical activities as standing, walking and lying and feeding activities as eating and ruminating activities were recorded with the Rumiwatch® system over one week immediately after the turning out (Period 1, P1) and 8 weeks later (Period 2, P2). Body weight recovery at pasture was significantly higher in R than in C cows and these changes were greater in CH than in SA cows (40 vs 12 kg in CH-R and CH-C; 25 vs 2 kg in SA-R and SA-C respectively, P<0.001). These differences were related to changes in feeding and physical activities especially during P1. The time spent in an upright position (included either standing or walking) was greater in R than in C cows in both breeds (12.7 vs 11.8 hours, P=0.07). These results are in accordance with the time spent eating which was higher in CH than in SA cows in both feeding levels (in average 7.08 vs 6.22 hours/day, P<0.08). In contrast, the ruminating time was higher in SA than in CH cows especially as they were underfed (11.3 vs 9.8 hours/day). With time (P2), differences in feeding and physical activities between breeds and previous feeding levels disappeared. Physical activity and time spent eating of suckling cows at turnout are significantly increased after an indoor feed restriction in accordance with a higher weight gain. In addition, SA cows were characterized by longer rumination time at pasture than CH cows.