Resumen de PF 03. Sward characteristics and winter performance of growing steers on native pasture

Claudio Rinaldi, Pablo Soca, F. Apeztequia, R. Orcasberro

• To study the Influence of some swards characteristics on weight daily gain (GDM) of Holstein steers in winter a trial was carried out between 04.29.91 and 07.22.91. 24 steers with inicial live weight (PIE) of 110 ± 25 kg were randomly asigned to the following forage allowances: 2.5, 5.0, 7.5 and 10.0 kg DM/100kg LW/day, adjusted by put and take method. The rotative grazed was with 7 days ocupation and 35 days rest. The sward measures were forage availability (DM/ha), sward height (ALT) and ungrazed areas at the begining (DISP) and the end (RECH) of each grazing period. Live weight was recorded every 7 days after 12 hours fasted. The GDM g/animal/day) was determinated by regression anlisys. The models that fits better for the animals performance were: GDM= 0.27 + 0.06ALTDISP - 0.006PIE (r2 = 0.70; CMe = 0.001; P < .01) and GDM = 0.212 + 0.007ALTRECH - 0.004PIE (r2 = 0.60; Cme = 0.008; P < .01). It permit to conclude, for the local condition, it is possible for the animals not to loose weight in winter grazing sward height over 3 cm.