ABSTRACT


Germán Klee G.1 e Ignacio Ruiz N.2
 
During 2 years (1971-73) an experiment was carried out to develop a beef production system based on 7 month old European X American Holstein autumn-born calves. A ladino white clover-perennial ryegrass mixture, mainly for grazing, and red clover alone, mainly for hay, were utilized. Likewise, some stilbestrol treatments were imposed to the steers during the different grazing periods.Stilbestrol used during the first grazing period (7-13 months old) did not increase considerably the daily gain of steers. However, a significant increment was obtained when stilbestrol was used in the fattening period (17½-24 months old). The feasibility to obtain a market weight (500 Kg) steer at 24 months old with a feeding regime based mainly on grazing and hay from pastures, was shown. For 6 month old calves, such a goal requires to reach minimum liveweights of 150-160, 270- 280, 330-340 and 500 Kg or more at 6-13-18 and 24 months old, respectively. This means that the daily gains should be around 0.60 to 0.65, 0.35 to 0.40 and 0.90 to1.00 Kg during the first grazing, second winter and second grazing period, respectively. The average output per hectare reached a value of about 807 Kg liveweight. Of the total grassland required for the system, 88% should be for grazing (white clover-grasses) and the other 12% should be for hay harvesting (red clover).
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1Ing. Agr., Programa Producción de Carne Bovina, Subestación Experimental Humán, Instituto de Investigaciones Agropecuarias (INIA), Casilla 767, Los Angeles, Chile.
2Ing. Agr., M. S., Ph. D., Programa Producción de Carne Bovina, Estación Experimental Quilamapu, INIA, Casilla 426, Chillán, Chile.