Effects of lactation length and weaning-to-conception interval on the subsequent litter size of purebred sows were estimated using an animal model. Data on 2,847 Landrace sows with 7,125 litters born between January 1989 and May 1997 and on 1,234 Yorkshire sows with 2,999 litters born between January 1990 and May 1997 were obtained from two Canadian selection herds. Sows having a lactation of l...

A study to evaluate the reproductive performance of Abergelle goat was carried out at Sekota District of Amhara National Regional State. On-farm flocks from two peasant associations were monitored for two years to collect data. Data collected included identification number of doe and kid, birth / kidding date, kid birth weight, sex of kid, post partum doe weight, litter size, parity of doe. Dat...

Examining data describing the sex composition of 1074 Caesarean-delivered litters of house mice, 253 Caesarean-delivered and 265 vaginally delivered litters of Mongolian gerbils, and 854 vaginally delivered litters of golden hamsters, we determined whether segregation of sexes between uterine horns and correlations between litter size and litter sex ratio were present in each of the three roden...

The dependence of activated mammary number on litter size was studied in standard type farmed mink in an attempt to clarify its effects on early kit mortality. The results showed highly positive correlations between litter size and the number of activated teats at 2 days, 4 weeks and 8 weeks of age. Total kit mortality was rather low and independent of litter size. The body weights of the mothe...

Stillbirth in swine ranges from 2 to 9%, resulting in a significant loss of piglets. Previous studies clearly indicate a relationship between prolonged birth intervals and stillbirth, but factors influencing birth intervals are not fully known. To characterize birth intervals and stillbirth, farrowing was recorded during three farrowing seasons. Blood samples were collected on d 110 and d 113 o...

the influence of melatonin receptor 1a gene on litter size was studied in 150 ewes from zel (n=100) and naeini (n=50) sheep breeds. two restriction fragment length polymorphism (rflp) analyses were done to determine all genotypes occurring by variations at mnli and rsai restriction sites. the m and c were the most frequent alleles in both of these breeds. the mm genotype was predominant in zel ...

Genetic parameters from both single-trait and bivariate analyses for prolificacy, weight, and wool traits were estimated using REML with animal models for Targhee sheep from data collected from 1950 to 1998 at the U.S. Sheep Experiment Station, Dubois, ID. Breeding values from both single-trait and seven-trait analyses calculated with the parameters estimated from the single-trait and bivariate...

Reproductive and early life-history traits can be considered aspects of either offspring or maternal phenotype, and their evolution will therefore depend on selection operating through offspring and maternal components of fitness. Furthermore, selection at these levels may be antagonistic, with optimal offspring and maternal fitness occurring at different phenotypic values. We examined selectio...

Porcine parvovirus (PPV) is widespread among swine. Our objective was to determine the prevalence of loosely housed sow herds in Finland with at least one animal with high (infection level) PPV antibodies and to gather basic knowledge about vaccination practices. In addition, selected factors associated with high antibody levels found in sows were examined. Altogether, 247 animals were sampled ...