Utilization of oat fodder (Avena sativa L., var. Nehuén) by grazing or soiling with Iactating dairy cows

Claudio Wernli K.1, Iván Guitart A.2 y Antonio Hargeaves B.3

Two methods of oats’ utilization as winter forage were studied (grazing vs soiling), between February and October 1980, at La Platina Experiment Station (INIA; Santiago). Productivity, losses and characteristics of the pasture, set on 8 blocks (each including both treatments, at random), were measured through sampling twice a week. Sixteen lactating Holstein cows were distributed to two treatments, on a randomized blocks design, and fed ad libitum a diet comprised by 30% oats and 70% alfalfa hay, plus 2 kg concentrate/animal/day. Oats’ growth was normal, with changes between the beginning and end of its growing period, in D.M. content, height, and DM. availability, from 8.7 to 15.0%, 59.1 to 89 cm, and 3.8 to 9.3 Ton/ha, respectively. Crude protein and ash centents and in vitro D.M. digestibility declined (D.M. basis), from 16.4to 8.5%, 14.1 to 9.0%, and 85.0 to 71.4%, respectively. This wasassociated with an increase in ceil wall and crude fiber contents, from 53.5 to 61.5% and 22.3 to 29.0%, respectively; the acid detergent fiber content and cellulose percentage also increased with time. The nutritional properties of the regrowths from soiling and grazing were similar. Utilization losses increased in time, average total losses being larger with grazing (54.2%) than with soiling (32.2%). The cests per unit of edible D.M., crude pretein, and digestible D.M., were higher with grazing ($8.4, $68.7 and $1 0.7/kg) than with soiling ($7.2; $57.6 and $9.2/kg), for the three stages of growth cons idered. lntake ef oats and of the total ration was slightly higher with seiling than with grazing; milk production, milk quality, and liveweight changes did net differ significantly between metheds ef utilizatien.

1 Estación Experimental La Platina (INIA), Casilla 439, Correo 3, Santiago, Chile.
2 Instituto de Desarrollo Agropecuario (INDAP), Mackenna 674, Osorno, Chile.
3 Estación Experimental Carillanca (INIA), Casilla 58-D, Temuco, Chile.