Climatic Characteristics of the Resting for Grazing Cattle in a Hilly Pasture during Summer Season

To clarify the relationships of air temperature and wind velocity to the resting site for grazing cattle in a hilly pasture, a raising-cattle herd consisting of 37-39 Herefords and Holsteins was rotatively grazed on three paddocks, and the resting sites for this herd were observed for 18 days during the summer season (July-Sep.). An observer recorded resting sites on a topographic map when more than 80% of the herd were resting around 14 : 00,22 : 00,2 : 00 and 10 : 00 h. Each paddock was classified into 5 or 6 blocks according to vegetation type and topographic elements. Wind velocity and air temperature were measured at a fixed point in each block, and the climatic characteristics of the resting sites were analyzed. The following results were obtained : 1) Wind velocity in each block at each measuring varied from 0.01 to 5.25 m/s, and the mean value through observations was 0.94 m/s. The air temperature in each block at each measuring varied from 12.9 to 31.5℃, and the mean value through observations was 21.4℃. 2) Differences in wind velocity among the blocks at each observation day ranged from 0.6-1.2 m/s in the paddock where the slope was only south or southeast-facing, which were smaller than in the other two paddocks where the aspect of the slope were various (P<0.05). Differences in air temperature among the blocks at each observation day ranged from 1-3℃ in all paddocks, and there was no significant difference in these values among the paddocks. 3) In the two paddocks where the elevation difference was about 60 m, the distribution of wind velocity and air temperature were more constant than that of the other paddock where the elevation difference was 40 m. 4) In the daytime (14 : 00 and 10 : 00 h), cattle frequently rested around the watering place (9 times in 34 observations except for the rain = 36%). In the residual observations, the daytime resting-site was frequently the site where the wind velocity was the highest among blocks (22 times in residual 25 observations = 88%, P<0.001). The climatic characteristics of nighttime resting-site were different between 22 : 00 and 2 : 00 h. In only one observation at night (22 : 00 h), cattle rested around the watering place. In the residual observations, resting-site (22 : 00 h) was frequently the site where the air temperature was the lowest among blocks (13 times in residual 15 observations = 85%, P<0.001). However, the resting site was not different between 22 : 00 and 2 : 00 h, and the nighttime resting-site (2 : 00h) had no particular climatic characteristics. Jpn.J.Livest.Management, 34(3) : 77-85,1999 Received March 16,1998 Accepted November 26,1998