ChileanJAR

This study was done at the La Platina Research Station (INIA). Santiago, Chile. The irrigated pasture (Trifolium pratense) was in a wheat rotation system; one half was first season and the other second season. Wheat was sown at the end of the second season. Two systems of beef production vvere studied: S1. Grazing from the end of September until April, without forage conservation; stocking rates were 5.0, 5.5, and 5.2 steers/ha, the first three seasons and 5.5 buliocks, the fourth season. 12 month-old animals, with 152-190 kg of L.W., were used. S2. The pasture was harvested for silage and hay up to November; grazing started in December; the first two years, 14.7 month-old steers were used; the last two years, 9 month-old bullocks vvere kept in a barn and fed silage and hay in winter; grazing started in September; stocking rates were 5.0 an./ha, the first season and 5.5 thereafter. In S1, L.W. gains/an./day, during the grazing periods (198 days, average) ranged from 0.75-0.94 kg. Liveweight/ha was over 1,000 kg in the first two seasons and 816 kg, in the following two, when utilization of the pasture was only until the 26 February. Animals were slaughtered with 18-21 months of age, a L.W. from 341-384 kg, and a carcass yield betvveen 54-570 /0. In S2, L.W. gains/an./day were 0.6, 0.8, 0.8, and 1.1 kg, during grazing periods of 167, 137,69, and 102 days, for seasons 1, 2, 3, and 4, respectively. In the barn gains ranged between 0.5-0.7 kg/day, with a conversion efficiency of 10.5 to 11.3. Meat production/ha was 896 kg, average for the first two years, and 628 kg, average of the last two years, utilizing the pasture until 10 February. Animals were finished at 21.1 months, with an average L. W. of 366 kg, in the first two years, and at 16.1 months, with 376 kg, in the last two. Carcass yields were 56, 59, and 57%, for the first three years.