Studies in grazing management. III The behaviour of dairy cows grazed under the close-folding and rotational systems of management

Extract

1. Two groups, each of six Ayrshire dairy cows, have been watched in the field for a total of twentytwo 24 hr. periods during the months May to September. No supplementary foods were fed at any time. One group grazed under a system of close-folding and the other in small rotational paddocks.

2. The effect of the different systems of management was small. It was clear, however, that closefolding increased the time spent in grazing and decreased the weight of herbage eaten. The milk yields from both groups were very similar.

3. A very constant pattern of behaviour over the 24 hr. period, similar for both groups, was observed. The most prolonged grazing period always occurred immediately after the cows returned from evening milking.

4. The amount of grazing during the hours of darkness was small at all times of the season but tended to increase as the evenings shortened and the nights lengthened. The cessation of evening grazing was closely linked with the fall of darkness at all times of the year.

5. The activities during the ‘day’ period were less regular but, nevertheless, showed a marked division into three main spells of grazing, of which one occurred immediately after morning milking, separated by two main spells of rest.

6. Stage of lactation, individual milk yield and live weight appeared to have no direct relation to the amount of time spent in grazing. Cows watched in both 1949 and 1950 grazed for very similar times despite differences in their stage of lactation.

7. Increasing defoliation of the paddock resulted in an increased grazing time by the rotationally grazed cows.

8. Close-folded cows grazed for a shorter time on herbage of low moisture content than on herbage of high moisture content, whilst eating virtually the same weight of dry matter.

9. Climatic changes to the extent met with in south-west Scotland had only a limited effect on the general pattern of grazing.

10. The physiological activities of dunging, urinating and drinking showed only small day to day variations.

11. The distance walked during grazing in the 24 hr. by one individual cow from each group showed only a slightly longer track for the rotationally grazed animal, the average distance being about 2000 yards.