Live mass, carcass and wool growth responses to supplementation of a roughage diet with sources of protein and energy in South African Mutton Merino lambs

Abstract

The effect of supplementing a diet of wheat straw plus urea with either 0, 100 or 200 g/d cottonseed oilcake meal .(CSM) in combination with either 0, 100 or 200 g/d  whole maize on wool and carcass growth of SA Mutton Merino lambs was studied. Voluntary intake of wheat straw was increased by CSM and decreased by maize (P < 0,01). Feed conversion ratio was improved by both supplements (P < 0,01). Although growth rate was increased by both supplements (P < 0,01), the response to CSM supplementation was almost double that for maize. The proportion of fat in the carcass was doubled by maize (P < 0,01), but was not affected by CSM. The proportion of fat in viscera was increased by both supplements (P < 0,01). Wool growth rate was increased by 89% and 226% when 100 or 200 g/d CSM were
fed respectively, and by 46% and 96% when corresponding amounts of maize were fed. Wool fibre diameter was increased by 26% with 200 g/d CSM and by 6% with 200 g/d maize. Acetate clearance rate was not significantly increased by maize or CSM (P > 0,05). An interaction between treatment effects for feed conversion ratio suggests that responses to protein supplementation will depend on the level of energy supplied.

Die invloed van katoensaadoliekoekmeel (KOK) teen peile van 0, 100 of 200 g/d in kombinasie met heel mielies teen 0, 100 of 200 g/d as byvoeding tot 'n dieet van koringstrooi plus ureum vir SA Vleismerino-lammers is ondersoek. Vrywillige inname van koringstrooi is verhoog deur KOK, maar verlaag deur mielies (P < 0,01). Voeromsetverhouding is deur albei bronne verbeter (P < 0,01). Alhoewel groeitempo deur albei bronne verhoog is (P < 0,01), was die respons tot KOK bykans dubbel die van mielies. Persentasie vet in die karkas is verdubbel deur mielies (P < 0,01),
maar is me deur KOK bei'nvloed me. Persentasie vet in die ingewande is egter deur albei bronne verhoog (P < 0,01). Wolgroeitempo is met 89% en 226% verhoog met 100 en 200 g/d KOK onderskeidelik en met 46% en 96% deur ooreenstemmende hoeveelhede mielies. Wolveseldikte is met 26% verhoog met 200 g/d KOK en met 6% met 200 g/d mielies. Asetaatverdwyningstempo is nie deur mielies of KOK verhoog me (P > 0,05). 'n Interaksie tussen behandelingseffekte vir voeromsetverhouding dui daarop dat die invloed van protei'enbyvoeding deur die vlak van energiebyvoeding bei'nvloed mag word.