- Influence of pelleting and the roughage : concentrate ratios of fattening rations for old merino sheep
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INFLUENCE OF PELLETING AND THE ROUGHAGE: CONCENTRATE RATIO OF FATTENING RATIONS FOR OLD MERINO SHEEP
J. G. CLOETE and J. W. ROSSOUW, Agricultural Research Institute for the Karoo Region, Middelburg, Cape Province.
Fattening rations, which consisted of either 67 and 33 percent lucerne meal and mealie meal or 59 and respectively, were given ad lib. to four groups of old Merino sheep in poor condition (± 31.8 kg body weight) for a period of 56 days. Rations were presented in the meal and pelleted forms. Sheep which received the pelleted rations gained in weight faster (P < 0.01), consumed 24 percent more feed (P < 0.01) and yielded heavier (P < 0.05), and superior carcasses than their meal-fed counterparts. When the concentrate component of the ration was increased from 33 to 41 percent sheep gained faster (P < 0.05) in body weight, yielded heavier (P < 0.05) carcasses of a higher grade than those on the low energy rations. Contrary to previous reports it was found that an increase in the concentrate component increased estimated net energy intakes by 9 percent. Only small differences were found in the mean efficiency of feed conversion between meal and pelleted rations in respect of live weight gain. However, increase in the concentrate component increased the mean efficiency of feed conversion by 19 percent in respect of carcass gain.
Pelleting had a negligible influence on the apparent digestibility of dry matter and on nitrogen retention. However, an increase in the concentrate component from 33 to 41 percent increased apparent dry matter digestibility from 64.7 to 71.7 percent and increased (P < 0.01) nitrogen retention by 74 percent compared with the low energy rations. Notwithstanding superior live weight and carcass weight gains it was found that the pelleting of fattening rations for sheep is advantageous only under certain conditions.
Agroanimalia 2 (4)