The relationshipb etweenp re- and post-weaningp erformanceo f lambs on Italian ryegrass

Abstract

The relationship between pre- and post-weaning performance of lambs on Italian ryegrass was investigated by grazing tambsa t differents tockingr ates.A positivec orrelationw asf ound betweenb oth the pre-weanings tockingr ate (P = 0.008)a nd weaningm ass( P = 0.001)a ndt he posGweaninga veraged aily gain, wherep ost-weanings tocking rate was not siSnificantw hen relatedt o animal performanceT. he correlationb etweent he w€aningm assi n early August and the final mass of lambs in Novembeq after 83 days on ryegnss, was highly significant (p = 0.001). Lambs stocked at a low stocking rate (20 ewes with lambVha) prior to weaning gained 13.3 kg, while lambs in the high pre-weanings tockingr ate( 36 ewesw ith lambVha)g ained1 1.9k g duringt hep ost-weaningp eriod.T he smaller lambs,o riginatingf tom pasturesw ith heavys tockingr ates,c ouldn ot catchu p on ryegrassp asturesi,n termso fmass gain, to achievea cceptables laughterm assw ithin a reasonablpee dod of time. The optimum pre-weaning stocking rate for ewes and lamb vhao n ryegrassw ill dependn oi only on the weaningm assd esired,b ut alsoo n the marketins strategyo f the producerf or the lambsafter weaning.

Die verwantskaptu ssenv oor-e n na-speenp restasiev anl ammersw, at Italiaansera aigraste env erskillendev eebeladings gewei het, is ondersoek'.n Positiewek orrelasieis gevindt ussenb eidev oorspeenv eebelading(P = 0.008) en speenmass(aP = 0.001)o p na-speeng emiddelded aagliksem assatoenamme,e t na-speenv eebeladingn ie betekenisvol verwanta and iereplestasinei e.D ie korrelasietu ssens peenmassvar oegi n Augustuse n die finale massav and ie lammersi n Novembern a 83 daeo p raaigrasis hoogsb etekenisvo(lP = 0.001).L ammersi n die yoorsDeenla e veebelading( 20 ooie met lammers/hah) et 13.3k g en die lammersin die hod voorspeenv eebelading(3 6 ooie met lammers/ ha)h et I1.9 kg in massag edurended ie na-speenp eriodet oegeneemD. ie kleinerl ammers,a fkomstigv an hod veebeladingsh,e t nie op die weidingi n termev anm assatoenamoep gevango m 'n aanvaarbarsel agmassbai nner edelike tyd te bereik nie. Die optimum voorspeenv eebeladingv ir ooie en lammers/hao p raaigrass al nie slegsb epaal word deurd ie speenmasswaa t bereikw il word nie,m aaro ok deurd ie bemarkilg strategiev and ie produsenmt et die lammers na speen,

Keywords: ltalian ryegrass, lambs, pre- and post-weaning performance.