PRODUCTION PARAMETERS FOR DOHNE MERINO SHEEP UNDER AN ACCELERATED, INTENSIVE LAMBING SYSTEM

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 (E(L)/E(M/ year) was 0,80 and the number of lambs born/ewe mated/year (L(B)/E(M)/year) was 1,25. Fecundity (L(B)/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.