| Autor: |
Bereskin, B., Frobish, L. T. |
| Zdroj: |
Journal of Animal Science; September 1981, Vol. 53 Issue: 3 p601-610, 10p |
| Abstrakt: |
The effects of various genetic and environmental factors on sow productivity traits were examined in 483 first-parity litter records of Duroc and Yorkshire sows in 7 year-seasons at the Beltsville Agricultural Research Center. Traits examined included litter size and weight at birth and at 21 days of age, sow weight gain during gestation, sow weight change during lactation, and length of gestation period. Age of sow, quadratic effects of sow weight at breeding and quadratic effects of sow weight gain during gestation did not significantly affect basic litter traits. Weight of sow at breeding affected only litter weight at birth. Sow weight gain during gestation had a positive association with litter size and weight at birth and with litter weight at 21 days. A sow productivity index expressed as a contemporary deviation had a heritability of 21 ± 9%, based on the regression of daughters on comparable midparental values. Milk yield significantly influenced lactation weight change by the sow. Little variation in gestation length was noted, but larger litter size had a slight negative association with that trait. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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