s:1635:"%T Productivity of Sumatran sheep in a system integrated with rubber plantation 
%A Iniguez L 
%A Sanchez M J 
%A Ginting S 
%X Productivity of Sumatran sheep, in a project integrating sheep and rubber plantations, was analyzed from 1985 to 1988. Ewes that had more than three lambings and managed under continuous exposure to rams had a nonseasonal distribution of lambings. Ewe weights averaged 22 kg at lambing and weaning, and were influenced (P < 0.01) by parity, nutrition and litter size. Repeatability of ewe weight at birth and weaning was 0.73 and 0.70, respectively. Lamb birth weights (1.8 kg) and weaning weights (9.3 kg), were heavier in male offspring (P < 0.01) and in small litters (P < 0.01). Litter size averaged 1.54 and its repeatability 0.32. Survival of singles (92%) and multiples (74%) were different by years (P < 0.01). Litter size and survival of multiples were affected by nutrition and ewe weight (P < 0.01). Weights of lambs born (2.74 kg) and weaned (11.45 kg) were significantly related to litter size and ewe weight. Weaned lamb output by ewes raising singles was 34–61% of those raising multiples. Repeatability of weights of lambs born and weaned was 0.38 and 0.36, respectively. Lambing interval averaged 201 days and repeatability 0.06. Parity, season, year and treatment had significant effects on lambing intervals. With a production rate of 1.82 lambings and some ewes weaning 3.6 lambs weighing 31.9 kg per 22 kg ewe per production year, Sumatran sheep have exceptional potential for accelerated lambing in integrated sheep and rubber plantation systems and humid tropical conditions. 
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