ABSTRACT


Ignacio Ruiz N.1, Ernesto Jahn B.2, Germán Klee G.3, Marcos Figueroa R.4 y Alejandro Ayres M.5
 
An experiment was carried out during 1969-70 at the Quilamapu Experiment Station, Chillán, to study the influence of 3 rates of winter gain of Holstein steers from 8-12 months of age period (first winter of spring-born claves) on a total beef production system based on a year-round forage program. The treatments and results were: a) High winter gain (0.79 Kg/day) obtained by winter grazing plus a dry sugar beet pulp-rapeseed meal supplement; b) Medium gain (0.38 Kg/day) obtained by grazing plus hay harvested from the forage plan, and c) Maintenance (-0.02 Kg/day) obtained with grazing alone. In the subsequent spring-summer-fall grazing season, the steers at the maintenance level showed the highest daily gain, but by fall they did not reach the live weight of steers from the other treatments; thus at the beginning of the second winter the steers 20 months old were not heavy enough to complete winter fattening within a 2 years-system of production. After the grazing period, the steers of all treatments were fed with a similar winter fattening ration (20-24 months of age). The treatments markedly influenced the carrying capacity and the output per hectare as well as the time to reach market weight (500 Kg).
For the high level of gain the market weight was reached at a relatively early date (august 1° =23 months) and the yield was 1967 Kg/ha of live weight per year. For the medium level, the daily gain was less but, the market weight was also reached in early spring (september 26 = 24½ months) and the output per hectare was 1.245 Kg of ilve weight. Winter feeding based on hay supplemented with 1,2 Kg of rapeseed real plus 1,2 Kg of dry sugar beet pulp also allowed the medium level steers to reach market weight during september. to of At the maintenance level, the steers needed 3 additional months of grazing reach market weight (december 17 = 27½ months) with an output per hectare 934 Kg live weight. The treatments also influenced the ratio land needed for grazingland need for harvesting.
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1Ing. Agr., Ph. D., Estaci6n Experimental Quilamapu, Instituto de Investigaciones Agropecuarias (INIA), Casilla 426, Chillán, Chile.
2Ing. Agr., M. S., Subestación Experimental Humán, Caoilla 767, Los Angeles, Chíle. Actualmente en V. P. I. y S. D., Blacksburg, Virginia.
3Ing. Agr., Subestación Experimental Humán, Casilla 767, Los Angeles.
4Ing. Agr., M. S., Estación Experimental Quilamapu, Chillán.
5Ing. Agr., Estación Experimental Quílamapu. Actualmente funcionario del Servicio Agrícola Ganadero (SAG).