Invloed van voedingstremming gedurende die soogfase op groei en woleienskappe by jong Merinoskape

Abstract

Effect of feed restriction in the early life of young Merino sheep on growth  performance and wool characteristics. The effect of feed restriction on the relative performance of young Merino sheep was investigated. Lambs were separated from their mothers between 24 and 48 h postpartum, divided into four random groups and artificially reared. Restriction was brought about by two commercial milk substitutes, viz. a calf (13% fat) and a lamb milk substitute (21% fat), each made available to the lambs at two different levels (ad libitum - 8 kg vs. restricted - 4 kg DM). The lamb and calf milk substitutes contained approximately 18,5% and 13,1% total solids respectively, on a liquid basis. The lambs were weaned on 30 ± 2 days and placed on a diet of commercial lamb creep feed pellets. No treatment effects were tested after weaning and lambs were reared under identical feed and environmental conditions. A significant difference (P < 0,05) in average daily live weight gain (ADO) between treatment groups from birth to weaning was recorded. ADOs of 73 g/d (restricted) and 161 g/d (ad libitum milk) were recorded. The restricted groups reached their original weaning mass within 5,4 days (P < 0,01) after weaning, compared with the 16,6 days of the ad libitum milk groups. Up to 15 kg live mass, lambs in the restricted groups had consumed 16% (P < 0,01) more creep feed than lambs in the ad libitum milk groups. Although the restricted groups produced significantly (P < 0,05) less greasy wool at six months of age, no  difference in greasy wool production was recorded at 18 months of age. Significantly (P < 0,05) higher clean fleece masses were, however, produced by the group which received lamb milk substitute as well as the restricted groups.

Die invloed van vroee voedingstremming (soogfase) op groei en woleienskappe by jong Merinoskape is ondersoek. Lammers is tussen 24 en 48 h postpartum van hul moeders verwyder, in vier ewekansige groepe verdeel en kUrismatig grootgemaak. Stremming is bewerkstellig deur twee kommersiele melksurrogate, n1. 'n kalf- (13% vet) en 'n lammelksurrogaat (21% vet), elk teen twee verskillende peile (strem - 4 kg vs. ad libitum - 8 kg DM), aan lammers beskikbaar te stel. Die lammelk- en kalfmelksurrogaat is sodanig verrneng dat 'n vastestofrnhoud van 18,5% en 13,1% onderskeidelik verkry is. Op 30 ± 2 dae is die lammers van melk gespeen en op 'n dieet van kommersiele lamkruipkorrels geplaas. Geen behandelingseffekte is hierna getoets nie en lammers is onder identiese voedings- en omgewingstoestande grootgemaak. 'n Betekenisvolle verskil (P < 0,05) in die gemiddelde daaglikse liggaamsmassatoename (GDT) het tussen behandelingsgroepe vanaf geboorte tot speen voorgekom. GDT's van 73 g/d (stremming) en 161 g/d (ad libitum - melk) is behaal. Die stremmingsgroepe het in 'n korter tyd (5,4 dae) (P < 0,01) weer hul oorspronklike speenmassa bereik nadat hulle gespeen is, in vergelyking met die ad libitum-melkgroepe (16,6 dae). Om 15 kg lewende massa te bereik, het die stremmingsgroepe gemiddeld 16% meer (P < 0,01) kruipvoer as die ad libitum-melkgroepe ingeneem. Hoewel die stremmingsgroepe betekenisvol (P < 0,05) minder rouwol op ses-maande-ouderdom geproduseer het, het geen verskille in rouwolproduksie, stapellengte, veseldikte en skoonopbrengspersentasie op 18-maande-ouderdom voorgekom nie. Hierteenoor is betekenisvol (P < 0,05) hoer skoonwolmassas by die lammelksurrogaatgroep en stremmingsgroepe aangetref.