Invasive Species Compendium

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Abstract

Productivity of grazing Angus steers of different structural size.

Abstract

64 Aberdeen-Angus steers, 200 days of age and with a small or medium frame (average frame score, 1.6 and 2.9 respectively), were reared on pasture (predominantly Festuca) at the Balcarce Experimental Station in Argentina, at a stocking rate of 1.8, 2.3, 2.8 or 3.3 steers/hectare, from 25 April to 22 December 1994. Steers were weighed every 14 days and backfat thickness between the 12th and 13th ribs was recorded at the end of the experiment. There were no differences between types in average daily gain. Small steers tended to be earlier maturing, showing higher backfat thickness (4.39 and 3.97 mm; P = 0.11) compared with medium-sized steers. Average daily gain was higher at lower stocking rates (0.612, 0.529, 0.414 and 0.375 kg/day for 1.8, 2.3, 2.8 and 3.3 steers/hectare respectively). Individual daily gain of the medium-sized steers was more variable across the seasons than that of small steers. Despite the difference in frame score between types, it was not possible to associate this with consistent differences in the response variables. Medium-sized steers did not have a greater productivity per surface unit than small steers.