Performance of beef steers on Smuts finger grass and Nile grass pasture in northern Natal 1. Effect of overwintering level and summer stocking rate

Abstract

In eacho f threec onsecutivey ears( 1987/88t o 1989/90),1 08w eaners teers( averageli ve mass= 192.5a nd standardd eviation = | .9 kg) were divided into threeg roupso f 36 steersa ndf ed to achieveg rowthr ateso f 0, 0.3 and 0.6 kg/steer/dayd uring winter. During the subsequenst ummer,t he steersf rom each wintering level were subdividedi nto six groups of six steers each, which grazed either Smuts finger grass (Digitaria eriantha spp eriantha) or Nile grass (Acroceras macrum) pasturese. acha t one of threes tockingr ates( 6, 8 and 10 steers/ha)R. otationalg razingw as applied.O n averages, teerss ubjectedt o winteringl evelso f 0,0.3 and 0.6 kg/days ubsequentlgya ined4 7.1 t 1.1,38.2t 2.1 and 34.9+ 2.2 kg/steero n Smuts finger grass and 63.5 t 2.2,55.7 + 2.3 and 42.8 t2.7 kg/steer on Nile grass pasture over a 90-day grazing period. Steerss ubjectedto stockingr ateso f 6, 8 and l0 steers/hgaa ined4 5.1t 2.0,39.2+ 1.8a nd3 5,8t 2.4kglsteero n Smutsf inger grassa nd 6l .8 x.2.1,5 8.7+ 2.2 and4 1.6x .2.8 kg/steeor n Nile grass.P redictione quationsfo r summerl ive massg ain and trnal live massw ere calculatedF. or all treatmentss, teersh adb etterl ive massg ainsw hen grazingN ile grasst han when grazingS mutsf ingerg rass[ 54.0+ 1.5a nd4 0.0t 1.2k g (P < 0.01),r espectivelyI]t. wasn ot clearw hethert he highers ummer growth-rateo n both pasturesin animalsw intereda t maintenancew asd uet o compensatoryg rowth or to relativelym ore grass/kgl ive weight beinga vailablet o the lighter animals. 

Speenosse(d rie groepev an 36 ossee lk; gemiddeldele wendem assa= 192.5e n standaardafwykin=g 1.9k g) is oor'n periode van drie opeenvolgendjea re (1987/88t ot 1989/90)g evoero m groeitempo'sv an 0,0.3 and 0.6 kg/dag gedurended ie winter te behaal.G edurended ie daaropvolgendseo meri s die osse,a fkomstigv an elkeenv an die oorwinteringspeilev, erdeel in sesg roepev an seso ssee lk en het hulle 6f Smutsvingergra(sD igitaria eriantha sppe riantha)6 f Nylgras( Acroceras macrurn)b ewei,e lkeent eene env an drie veebelading(s6 , 8 en l0 osse/ha)W. isselweidingis toegepasO. or die jare het osse met wintergroeitempovsa n 0, 0.3 en 0.6 kg/dag,m assatoenamevsa n 47.1 t 1.1,38.2 + 2.1 en 34.9 + 2.2kg/os op Smutsvingergrase-n 63.5 + 2.2, 55.1t 2.3 en 42.8 x.2.7 kgloso p Nylgrasweidingo or 'n weiperiodev an 90 daeb ehaal. Ossew at aanv eebeladingvsa n6 , 8 en 10o sse/hao nderwerpw as,h et massatoenamveasn 45.1+ 2.0,39.2 + 1.8e n 35.8+ 2.4kg/os op Smutsvingergraesn 61.8+ 2.1,58.7+ 2.2 en 41.6x .2.8 kg op Nylgrasg ehad.V oorspellingsvergelykinigss berekenv ir iewendemassa-toenamooer die somerperiode n vir finalem assaO. or alle behandelingsh et osseg roterl ewendemassa- toenamoeps Nylgrasweidinga s op Smutsvingergrasweidignegt oon[ 54.0 t 1.5 en 40.0 + l.2kg (P < 0.01), onderskeidelikl. Dit was onduidelik of die diere, wat teen onderhoud oorwinter is, se hoer somergroei op albei weidings toegeskryfk on word aank ompensatoriesger oei of dat dit die gevolgv an relatiefm eerg rasb eskikbaara and ie ligter diere was.

Keywords: Live mass gain, stocking rate, subtropical pastures.