Scrapie is one of several transmissible spongiform encephalopathies of livestock. Disease susceptibility is linked to polymorphisms in the normal prion protein gene that encodes the mammalian prion precursor. Codon 171 of this gene is a major determinant of scrapie susceptibility. Selection for arginine (R) at codon 171 is encouraged by the USDA to decrease the incidence of scrapie. Objectives ...

OBJECTIVE Different studies have shown an association of TLR4 polymorphisms with susceptibility/resistance to malaria disease. In the current immunogenetic study, we assessed the TLR4 genotypes formed by the two common single nucleotide polymorphisms (SNPs) (Asp299Gly and Thr399Ile) in the co-segregate state in Baluchi Plasmodium falciparum infected and healthy populations from malaria hypoende...

in this study, the number of 1802 longevity records of ewes collected during 1989 to 2010 in breeding station of lori-bakhtiari sheep flocks were used to estimate of genetic, environmental and phenotypic trends for economic lifetime. the breeding values of a ewe’s lifetime were estimated by restricted maximum likelihood procedure under an animal model of univariate analysis. the best linear unb...

Ewe productivity is synonymous with annual litter-weight weaned (LWW) per ewe exposed to rams for breeding, and LWW is largely a function of number of lambs born (NLB) and weaned (NLW). Selecting for LWW should increase litter size and numbers of ewe-ram co-twins. Thus, we used historical records to determine whether sex of co-twin affected lifetime productivity of twinborn ewes. United States ...

Factors affecting ewe prolificacy (number of lambs born per ewe lambing) were evaluated using records on 9705 Targhee, 12,721 Suffolk, and 7231 Polypay lambings from flocks participating in the US National Sheep Improvement Program. Factors considered were ewe age and season of lambing. Prolificacy was affected by age of the ewe (P<0.001) and was highest for ewes lambing between 4 and either 7 ...

A resource population of ewes derived from Dorset and Romanov grandparents was generated over 5 yr to provide genotypic and phenotypic data to estimate effects of each callipyge genotype on component traits of reproduction. Effects on ovulation rate were estimated from data recorded by examination of ovaries from serially slaughtered ewe lambs (n = 174) born in 1994 and 1995. Productivity and l...

introduction the mating of related individuals produces an inbred offspring and leads to an increased homozygosity in the progeny, genetic variance decrease within families and increase between families. the ration of homozygosity for individuals was calculated by inbreeding coefficient. inbred individuals may carry two alleles at a locus that are replicated from one gene in the previous genera...

A new mutation in the bone morphogenetic protein 15 (BMP15) gene (FecX allele) causing increased prolificacy in heterozygous (R+) and sterility in homozygous ewes has been recently described in Rasa Aragonesa, a low-prolificacy Mediterranean breed. The current study determined, first, the effect of this polymorphism on natural and eCG-induced ovulation rate (OR) and the effect of eCG dose on re...