ABSTRACT.
Intensive beef production with Hereford bullocks, fed different winter supplements, under grazing

Enrique Siebaid Sch.1, Carmen Massai C.2 y Mario Matzner K.1
 

Four winter feeding regimes, for intensive systems of meat production using intact Hereford males, were evaluated in the Osorno Central Plain, using a complete randomized design:
I Pasture + 2.7kg of hay (DM..);
II Pasture + 2.0 kgof hay + 1.7kg of oat grain (D.M.);
III Pasture + 1.9 kg of hay +0.8 kg of oat grain + 0.8 kg of potatoes (D.M.);
IV Pasture + 2.0 kg of hay + 1.3 kg of potatoes.
Live weight gains were: 0.44, 0.58, 0.63, and 0.55 kg/head/day, for treatments I, II, III, and IV, respectively, during the supplementation period. Treatment l was statisticaly higher than the others.
After the winter season, the bullocks grazed together the same pastures used during the winter: a mixture of Dactylis glomerata, LoIium sp, Trifolium repens, Holcus lanatus, and other species of less importance. Gain rate was similar for all treatments (about 0.94 kg/animal/day) during the grazing period.
At 15 months of age, bullocks reached a uve weight of 348 to 368 kg. Carcass characteristics did not differ among treatments, reaching en average centesimal yield of about 60%.
From April to January, pasture yleld was about 8.8 ton DM/ha; percents of utilization were 59.9 and 71.3, during winter and spring, respectively; depending on the treatment, output per hectare ranged from 623 to 705 kg of live weight.
Considering an area of 25 ha, the highest profit (19.8%) was given by Treatment I.

Keywords:
1 Estación Experimental Remehue (INIA), Casilla 1110, Osorno, Chile.
2 Actualmente estudiante de Postgrado de la Fac. deCiencias Agrarias, Veterinarias y Forestales, U. de Chile.