Author
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Snowder, Gary |
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Submitted to: FAO Technical Reports
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/5/2000 Publication Date: 1/26/2001 Citation: Snowder, G.D. Characteristics of the American Polypay: A Review. 2001. Animal Genetic Resources Information 29:19-30, Food and Animal Organization, Via delle Terme di Caracalla 1, 00100 Rome, Italy. Interpretive Summary: The objective of this study was to review the scientific literature characterizing the Polypay sheep breed. The Polypay sheep breed was developed at the U.S. Sheep Experiment Station in the late 1970's. The breed has a reproductive capacity markedly superior to that of domestic western range breeds.The Polypay is a four breed composite of Targhee, Rambouillet, Dorset and Finnish Landrace breeds. It is a medium-sized wool sheep with a smooth body and a poll head. Comparative studies with other US domestic breeds have shown the Polypay to have earlier sexual maturity, higher fertility and prolificacy rates. Mature ewes give birth to an average of 2.4 lambs and wean an average total litter weight of 140 pounds per ewe at 120 days post partum. Lamb survival rates to 21 and 120 days are greater than those of other breeds compared. Average individual lamb weaning weight at 120 days (79.5 pounds) exceeded that for Rambouillet and Targhee lambs (75.9 and 74.4 pounds, respectively). Polypay carcasses are similar to those of Rambouillet and Targhee for dressing percentage, body wall thickness, kidney and pelvic fat, and ribeye area. Measures of carcass fat are less in the Polypay when compared to the Rambouillet and Targhee while qualitative leg scores for the Polypay were more favorable. Wool characteristics are defined as a coarse to medium grade. Raw fleece weights are considered light and range from 6 to 10 pounds. Yield of clean wool is approximately 57 percent. Economic evaluations favored the Polypay in all production systems considered with 15 to 36% increase in sales or profits compared to other US domestic breeds. Technical Abstract: The Polypay sheep breed was developed at the U.S. Sheep Experiment Station with a reproductive capacity markedly superior to that of domestic western range breeds. The Polypay is a four breed composite of Targhee, Rambouillet, Dorset and Finnish Landrace breeds. It is a medium-sized wool sheep with a smooth body and a poll head. Comparative studies with other US domestic breeds have shown the Polypay to have earlier sexual maturity, higher fertility and prolificacy rates. Mature ewes give birth to an average of 2.4 lambs and wean an average total litter weight of 63.8 kg per ewe at 120 days post partum. Lamb survival rates to 21 and 120 days are greater than those of other breeds compared. Average individual lamb weaning weight at 120 days (36.1 kg) exceeded that for Rambouillet and Targhee lambs (34.5 and 33.8 kg, respectively). Polypay carcasses are similar to those of Rambouillet and Targhee for dressing percentage, body wall thickness, kidney and pelvic fat, and ribeye area. Measures of carcass fat are less in the Polypay when compared to the Rambouillet and Targhee while qualitative leg scores for the Polypay were more favorable. Wool characteristics are defined as a coarse to medium grade wool with a fiber diameter ranging from 24 to 33 um. Fiber staple length ranges from 7.6 to 12.7 cm with a common mean of approximately 10 cm. Raw fleece weights are considered light and range from 2.7 to 4.5 kg. Yield of clean wool is approximately 57 percent. Economic evaluations favored the Polypay in all production systems considered with 15 to 36% increase in sales or profits compared to other US domestic breeds. |
