Efficiency of feed conversiond uring food restriction and realimentation

Abstract

Sixty Merino lambs weighing 25 kg were randomly allotted to six different feeding levels as follows: ad libitum, S0%,71%, 65%,55% and 45% ad libitum. Individual intakes and live masses were determined weekly. From 25-33 kg live mass the lambs received restricted feeding except for the control groups on ad /lb intakes. At 33 kg live mass, half of each group was slaughtered and the remainder received ad libitum feed to 45 kg live mass. The 55% and 45%a d libitum groups were put on ad libitum feed at 31 and 28 kg live mass because the ad libitum groups had already reached 45 kg live mass and had been slaughtered. During the restriction phase, efficiency of feed conversion decreased as restriction increased. For the first week of the realimentationp hase,e fficiencyo f feed conversioni ncreased as restriction increased. From the second week of the realimentationp hase,e fficiencyo f feed conversionw as the same for the ad libitum, 50%,71%on d 65%a d libitum groups (79,4 MJ DE/kg LWG) while the efficiency of feed conversion for the 55% and 45% a d tibitum groups decreasedt o 86,1a nd 94,1 MJ DE/kg LWG, respectively.

Sestig Merinolammersv an 25 kg elk is ewekansiga an ses verskillendev oedingspeilet oegekens oos volg: ad libitum, 50%, 71%,6 5%, 55%a nd 45% ad libitum. Individuelev oerinnames en massasi s weekl iksi ngesamelV. anaf2 5-33 kg lewende massa het die lammers beperkte voeding ontvang behalwe die ad libitum groep wat die kontrole groep was. Op 33 kg lewende massa is die helfte van elke groep geslag en is die res op ad 83 libitum geplaas tot op 45 kg lewende massa. Die 55% en 45% ad libitum groepei s op onderskeidelik3 1 en 28 kg lewende massa op ad libitum geplaas omdat die ad libitum groep 45 kg lewende massa bereik het en geslag is. Gedurended ie beperkingsfaseh et doeltreffendheidv an voeromset afgeneem soos die beperking toegneem het. Vir die eerstew eek van die realimentasiefa se het doeltreffendheid van voeromset toegeneem soos wat die beperking toegeneem het "V anafd ie tweedew eek van die real imentasiefa se was die doeltreffendheidv an voeromsetv an die ad libitum,80%,71% en 65% ad libitum groepe dieselfde nl.79,4 MJ VE/kg lewendige massa toenamet erwyl die doeltreffendheidv an voeromset van die 55% en 45%a d libitum groepe verswak het na onderskeidelik 86,1 en 94,1 MJ VE/kg lewendige massa toename.

Keywords: Efficiency,feed conversion,restriction,realimentation, sheep