nan Subandriyo

Productivity of Sumateran Composite dan Barbados Cross sheep breed in the field condition

Two years field study has been carried out in the Purwakarta district , West Java, to evaluate sheep productivity of Sumateran Composite (K) and Barbados cross (BC) breeds introduced to the farmers, compared with locally thin tail sheep breed (L) that were maintained by the farmers. Genotype compositions of K sheep were Barbados Blackbelly 25%, St. Croix 25%, and Sumateran sheep 50%; and for BC were Barbados Blackbelly 50% and Sumateran sheep 50%. Sheep those were introduced was new breed from breeding improvement of Indonesian Research Institute for Animal Production. Litter size of K, BC, and L ewes was 1.3; 1.4; and 1.5 respectively. Pre-weaning mortality rate were 5.0; 5.0 and 8.0% respectively for K, BC, and L lambs. Ewe Reproduction Rate (LRI = number of lamb at weaning/ewe/year) of L (2.14) was higher than BC (2.0) and K (1.85). The ewe productivity (PI = kg lambs/ewe/year) is the average of weaning weight timed LRI. Because the weaning weight of L (7.0 kg) were significantly lowest than BC (10.5 kg) and K (9.25 kg) will affect on PI. PI of L (14.98) ewe were significantly (P<00.5) lowest than BC (21) and K (17.11). Body weight of crossbred (K X L and BCxL) under the same physiologic status were similarly with BC and K. According to the result of productivity evaluation of introduced sheep breed in the field condition, can be sumarize that productivity of K and BC sheep were significantly better than locally thin tail sheep. Key Words : Sumatera Composite, Barbados Blackbelly, Thin Tail Sheep, Productivity, Traditional Rearing

Performances of composite genotype resulting from crossingbetween local sumatera and hair sheep under confinement condition

Under semi-intensive conditions, the composite genotype (K) (25% Barbados Blackbelly; BB, 25% St. Croix; SC, 50% Sumatra Thin Tail; DETS) showed relatively have similar weaning weight as compared to other contemporary crossbred, therefore under intensive conditions (confined), they are expected to have better performances. The objective of the study are to find performances of the second generation composite genotype lambs and the first generation performances of the ewes, as well as several genetics parameters under intensive conditions, and compared to the Barbados Blackbelly Cross (BC) as contemporary crossbred. The growth of pre- and post-weaning of BB crossbred (BC) and the second generation of composite genotype (K-F2) are relatively the same. Growth curve using Von Bertalanffy model with the equation of Wt (t) = A*(1-B*e**(- K*t)), show that the equation for BC is Wt (t) = 26.8(1-0.92e**(-0.01t) and for K-F2 is Wt(t) = 26.1(1-0.92e**(-0.01t). This equation indicate that the growth of BC and K-F2 is not significantly different. The BC and K-F2 genotype reach maturity at the weight of 26.8 and 26.1 kg, respectively, and both with rate of reaching maturity of 0.01. Mating weight and weight at lambing of those two genotypes are around 29 - 30 kg dan 31 kg, respectively. The mean of litter size of BC and K-F1 are 1.52 and 1.48, respectively or around 1.5. The average litter size at weaning are 1.39 and 1.34, respectively for BC and K-F1. This means that pre-weaning mortality are around 5.37 and 9.76%, respectively for BC and K-F1. The lambing interval of BC and K-F1 are 211 and 223 days, or 0.58 and 0.61 year, respectively. Therefore the reproductive rate (RR) of the respective genotype are 1.39/0.58 = 2.39 and 1.34/0.61 = 2.19, respectively. The average of litter weight at weaning (LWW) of BC x BC, SC crossbred (HC) x BC and K-F1 x K-F1 are 11.62, 12.60 and 11.83 kg, respectively. Therefore based on the ewe genotype the LWW of BC and K-F1 are 11.74 and 11.83 kg, respectively. Flock productivity (FP) for those two genotypes per year are 20.24 and 19.39 kg, respectively for BC and K-F1. Dam productivity index (DPI) that calculated as /ewe weight for those two genotypes are 0.67 and 0.66, respectively for BC and K-F1. Meanwhile, the flock efficiency index (FEI) that calculated as FEI = FP/ewe weight0.75 for the respective genotypes are 1.57 and 1.54 for BC and K-F1. The estimates of repeatability of litter weight at weaning show relatively low value (0,092), therefore the estimate of MPPA (Most Probable Producing Ability) for predicting the future productivity is relatively the same. The estimate of MPPA for litter weight at weaning (LWW) for the respective genotype are 11.79 and 11.81 kg, respectively for BC and K-F1. Results of the study show that performances of composite genotypes (F) and the contemporary crossbred (BC) are relatively similar in the traits of growth, dam productivity and the estimate of MPPA. Key words : Composite sheep, performance of production and reproduction, intensif condition