Grazing management practices and their relationship to the behaviour and grazing habits of cattle

Abstract

1. The grazing habits of Aberdeen-Angus and Hereford beef cows, on pasture without supplementary feed, were studied over continuous periods of 24 hr. during the months of July, August and September. The pastures were from 3 to 7 acres in extent and contained a good growth of Kentucky bluegrass and wild white clover, with an average moisture content of 72 %.2. During each 24 hr. period the cows spent from 7 to 8 hr. only in grazing, whatever the length of the herbage. Of this time, only some 5 hr. could be counted as actually employed in gathering herbage, as the remainder was spent in walking short distances and in selecting the area to be grazed. On the average 60 % of the grazing was performed by day, when the average distance travelled was 2 miles, and 40 % by night, when the cows travelled only about half a mile. With a dense sward of from 4 to 5 in. in height, representing about 4500 lb. green herbage to the acre, each cow was able to consume about 150 lb. of green herbage, or 32 lb. of dry matter, daily. As the amount of green herbage decreased through grazing to 2200 and 1100 lb. respectively, the daily intake was correspondingly reduced to 90 lb. (20 lb. dry matter) and 45 lb. (10 lb. dry matter). On a pasture containing about 5000 lb. green herbage of about 10 in. in height, the average daily intake was only 70 lb. (20 lb. dry matter).3. Records were made also (the average figure for the 24 hr. period being given in parentheses) of time spent in lying down (12 hr.); time spent in cudding (7 hr.); frequency of defaecation (12); amount of manure (46 lb., covering an area of 8 sq. ft.); frequency of urination (9); frequency of drinking (once only, usually in late afternoon); and frequency of suckling calf (3, each for about 15 min. at 8 hr. intervals).4. The application of the results to pasture management is discussed.