GRAZING HABIT OF HOLSTEIN COWS DURING THE RAINY-SEASON WITH DIFFERENTPADDOCKS OF FERTILIZED STAR GRASS (CYNODON-NLEMFUENSIS)

A study was carried out in the rainy season with fertilized star grass to study the behaviour of Holstein cows and some direct effects of cl imate. Sixty six cows were used in a completely randomized design and decided in three homogeneous groups in the following treatments: A)8 p addocks, B) 4 paddocks and C) paddocks. The stocking rate was 3.6 cows /ha. Grazing time was at 7 a.m. to 10 a.m. and from 3 p.m. to 5 a.m. T heir behaviour during the first 15 days of September did not show diff erences between 8, 4 and 2 paddocks in grazing or standing time in the morning, but it was longer with 2 paddocks during grazing time in the afternoon and in the morning + afternoon with no differences between 8 and Resting time was longer with 8 paddocks 4 paddocks. compared wit h 2. The reverse occurred with waling time which was of fewer hours wi th 8 paddocks. No differences between 8 and 4 paddocks were encountere d. The behaviour was similar with the three grazing methods 25 days la ter. Grazing was mainly during daylight, specially early in the mornin g and late in the afternoon. Night grazing was 37% of the total grazin g hours. During the afternoon the cows were maintained under intensive grazing, depsite the adverse climatic conditions. The values of recta l temperature and respiratory frequency did not show differences betwe en treatments with average values of 39.05 degrees C and 51 rpm. The h ematocrits and erythrocytes in blood were below the normal values. It is concluded that under the 2 paddock system, Holstein cows employed m ore time searching for feed and that the rectal temperature and the re spiratory frequency confirm that the rainy season is not adequate for this type of cows. Thus, it is suggested that the afternoon-night graz ing of Holstein cows should be limited during the rainy season regardl ess the number of paddocks, at least if no shading facilities are avai lable.