ABSTRACT


G. F. Cubillos1, R. F. Barnes2, C. H. Noller3, D. Cerviño4 y F. Ortiz5
 
Perennial ryegrass, Lolium perenne L., was sampled biweekly on the same day at two locations in southern Chile for eight sampling dates. The two locations, Temucoand Osorno, are in the humid zone. The crude protein, crude fiber, ether extract, invitro dry matter digestibility ( IVDMD) a nd mineral composition were determined.Crude protein decreased at the rate of 0.52% per day during the first three harvestsand 0.08% per day thereafter reaching a low of 3.9% at the final harvest. Crude fiberincreased from 23.7 to 41.9% with advance in age and ether extract decreased from4.0 to 1.2%. The IVDMD without added urea declined on average of 0.4570 per dayduring the harvesting sequence and 0.32% with added urea. The average IVDMD was60.2% without added urea and 65.770 with added urea.Changes in mineral composition of the forages with advancing plant age were similarat both locations. Phosphorus decreased from 0.42 to 0.10%, magnesium from 0.18to 0.10%, and potassium from 2.42 to 1.07%. Copper averaged 8.5 mg/Kg at Osornoand 11.7 at Temuco. The significance of the changes in forage composition on animalproduction is discussed.
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1Ing Agr. Ph. D. Coordinador de Investigación en Producción Animal, Instituto de Investigaciones Agropecuarias,Casilla 5427, Santiago de Chile.
2Agrónomo Investigador, USDA, Servicio de Investigación Agrícola y Profesor Asociado de Agronomía, Purdue University, Lafayette, Indiana.
3Profesor de Zootecnia, purdue University, Lafayette, Indiana.
4Ing. Agr. Estación Experimental Barro Blanco, Osorno, Chile.
5Ing. Agr. M S. Proyecto Praderas Húmedas y ProducciónAnimal, Estación Exoerimental Carillanca, Temuco, Chile.