Effects of eight grazing systems on carcass mass gains of steers grazing irrigated Cynodon aethiopicus pastures.

Eight grazing systems were compared on irrigated Cynodon aethiopicus pastures which received 650kg N, 36kg P and 200kg dolomitic limestone/ha, annually. There were either one, two, three, six or 18 paddocks in the systems, the single paddock system being continuously grazed. The others were rotational systems with various periods of grazing and of resting. Using the comparative slaughter technique carcass mass gains of crossbred Hereford/Afrikaner steers were calculated. Three-year mean carcass mass gains over stocking rates from 12 to 18 steers/ha ranged from 872 to 997kg/ha. None of the rotational systems were better than continuous grazing. Estimates of amounts of herbage available for grazing in each system showed that there was least in the continuous grazed and most in the multi-paddock systems where there were long periods of rest between successive grazing.Keywords: Beef production; Carcass mass gains; continuous grazing; Cynodon aethiopicus; Grazing management; Grazing systems; herbage; Irrigated pastures; pastures; resting; Rotational grazing systems; Star grass; Steers; stocking rates; zimbabweJournal of the Grassland Society of Southern Africa