Production parameters for Dohne Merino sheep under an accelerated, intensive lambing system

Abstract

Data of lambing records from 1984 to 1989, which comprised 914 ewe lambing years and 1522 lambing opportunities, were used to investigate overall productive performance of Dohne Merino ewes under an accelerated lambing system. Ewes were exposed to three fixed 30-day mating periods per year to lamb during  February/March (first season), June/ July (second season) and October/November (third season). The number of ewes lambed/ewes mated/year (&./EM/ year) was 0,80 and the number of lambs born/ewe mated/year (La/EM/year) was 1,25. Fecundity (La/lambing) was 1,32. The average interlambing period was 11,09 :!: 3,66 months while the number of lambings recorded/lambing opportunity was 0,61 :!: 0,24. Average survival rate from birth to 100 days was 0,83 and was influenced by both year and season of birth. Average weaning mass was 16,73 :!: 2,72 kg at 56,3 :!: 8,6 days on average, and average 100-day mass was 24,99 :!: 5,17 kg. Body mass of lambs at 100 days was significantly (P < 0,001) influenced by year of birth, season of birth, sex of lamb and birth status. Lambs born in winter were 16,2% heavier than those born in spring and 20,9% heavier than those born in  summer/autumn. Management practice should take these effects into account.

Data van larnrekords vanaf 1984 tot 1989, bestaande uit 914 ooijare en 1522  lamgeleenthede, is gebruik om die totale produksie van Dohne Merino-ooie in 'n versnelde paringstelsel te ondersoek. Ooie is vir drie vaste periodes van 30 dae
elk by die ramme geplaas om gedurende Februarie/Maart (eerste seisoen), Junie/Julie (tweede seisoen) en Oktober/ November (derde seisoen) te lam. Aantal ooie gelam/ooi/jaar gepaar (&./EM/jaar) was 0,80 en aantal lammers gebore/ooi/jaar gepaar (Lg/EM/jaar) was 1,25. Die fekunditeit (La/lamming) was 1,32. Die gemiddelde interlamperiode was 11,09 :!: 3,66 maande terwyl die aantallammings per lamgeleentheid aangeteken, 0,61 :!: 0,24 was. Die gemiddelde oorlewingstempo vanaf geboorte tot 100 dae was 0,83 en is deur beide jaar en seisoen van geboorte
beinvloed. Gemiddelde speenmassa was 16,73:!: 2,72 kg op 'n gemiddelde  ouderdom van 56,3 :!: 8,6 dae en die gemiddelde l00-dae-massa was 24,99:!:: 5,17 kg. Lammassa op 100 dae is betekenisvol (P < 0,001) deur jaar van geboorte, seisoen van geboorte, geslag van die lam en geboortestatus beinvloed. Lammers wat in die winter gebore is het op 100 dae 16,2% swaarder as die in die lente en 20,9% swaarder as die in die somer gebore, geweeg. In die toepassing van bestuurspraktyke behoort hierdie effekte in ag geneem te word.