Genetic and Phenotypic Parameters for Sow Productivity

Abstract

Data from 609 purebred Yorkshire, Hampshire and Duroc litters were utilized to obtain genetic and environmental parameter estimates for litter number and weight traits at birth, 21 d (first creep) and 42 d (weaning) considered as traits of the sow. Differences among paternal half-sib sets of sows were analyzed. Heritability estimates from this study were .26 +/- .12, .28 +/- .12 and .30 +/- .12 for litter size at birth, 21 and 42 d and .54 +/- .13, .17 +/- .11 and .15 +/- .11 for litter weights at those times, respectively. These estimates indicated that the dam's genetic contribution to litter weight was higher for prenatal growth than during nursing. The heritabilities for litter size were encouraging for within breed selection. Genetic correlations among litter sizes and genetic correlations among litter weights at birth, 21 and 42 d were large and positive. Large, positive genetic correlations also were found between litter size and weight at each of the three times. Negative correlations between litter size and average pig weight at both birth and 21 d and between litter size at birth and average pig weight at 21 d indicated that larger litters were associated genetically with smaller pigs. Phenotypic and environmental correlations generally indicated the same associations.

Population parameter estimates for performance and reproductive traits in Polish Large White nucleus herds.

“…Genetic and phenotypic correlations between reproductive traits were large and positive and were in general agreement with most estimates from the literature (Omtvedt et , 1966;Edwards and Omtvedt, 1971; Lam- berson, 1990). The phenotypic correlations between NBA and N21 and between NBA and W21 were much larger than those reported by Young et al (1978), Bereskin (1984), Irvin and Swiger (1984) and Ferguson et al (1985). Much lower estimates for all correlations between the same traits were reported by McCarter et al (1987), but their estimates were based on records adjusted for subsequent parity.…”

Effects of porcine stress syndrome genotype on maternal traits in swine

“…Commercial producers may be more likely to cull females having rebreeding problems. Irvin and Swiger (1984) Landrace field data, respectively. summarized heritability estimates for various maternal performance traits.…”

Pork Production Systems

“…In the process of identification for registration, breeders have long recorded the number of pigs born alive. Following research at Ohio State University (Irvin and Swiger 1984), a Sow Productiv-ity Index was developed to evaluate and compare sows through a function of number born alive (NBA) and the weight of nursed litter at 21 days of age (L W21). Standardization of litter size by cross-fostering is recommended and the recorded L W21 is mathematically adjusted for number after transfer (NAT).…”