This study investigated follicular development during and after postweaning altrenogest treatment of primiparous sows in relation to subsequent reproductive performance. Primiparous sows (n = 259) were randomly assigned at weaning (d 0) to 1 of 4 groups: control (no altrenogest, n = 71), RU4 (20 mg of altrenogest from d -1 to 2, n = 62), RU8 (20 mg of altrenogest from d -1 to 6, n = 65), or RU1...

The reproductive performance of 255 Rambouillet (R), Dorset (D), Finnsheep (F) and F1 ewes born in 1978-1979 (group I) and 1979-1980 (group II) and managed in a semiconfinement fall/winter lambing system was evaluated through 4 yr of age of all ewes and through 5 yr for a portion of group I ewes. Ewes were with rams from approximately May 1 to late September each year, with a 2-wk break late in...

At the last Pig Genetics Workshop two papers described aspects of the lost potential in pig production at the commercial level. Black (2000) estimated that slower growth, reduced efficiency of feed use and fatter carcases decreased the profitability of pig enterprises by as much as 25%. Walters (2000) estimated that successful progress had been achieved in backfat reduction but that there were ...

1 Key Laboratory of Farm Animal Genetic Resources and Utilization of the Ministry of Agriculture, Institute of Animal Science, Chinese Academy of Agricultural Sciences, 100193 Beijing, China 2 College of Animal Science and Technology, Anhui Agricultural University, 230036 Hefei, China 3 College of Animal Science and Technology, Hebei Agricultural University, 071000 Baoding, China 4 State Key La...

Direct selection for ovulation rate, uterine capacity, litter size and embryo survival and selection for indexes of ovulation rate with each of the remaining traits were simulated for a swine population. The relationships among these traits were determined from a simulation model that assumed that litter size was always less than or equal to both ovulation rate and uterine capacity. Heritabilit...

a selection program is being implemented to improve meat production in makooei sheep. increasing litter size per ewe is the main objective, but possible repercussions on weight traits of lambs should be considered. the aim of this study was to estimate heritability along with genetic and phenotypic correlations between ewe's reproductive vs. weight traits in makooei ewes. data were comprised of...

In this study, we investigated the relationship between the genetic polymorphism of growth differentiation factor 9 (GDF9) genes and the litter size in 384 individuals of five breeds of black goats. Four pairs of primers were designed to detect single nucleotide polymorphism of GDF9 gene in goats by PCR-SSCP. The least square was used to analyze the relation between different genotypes and the ...

The effects of postnatal litter size on preand postweaning growth, daughter 's litter size and rebreeding performance of the dam were examined in rats that had undergone 14 generations of selection for rate (LG) or efficiency (LE) of postweaning protein gain followed by relaxed selection, and in a randomly selected control line (C). Data came from generations 23 to 24 (standardized litters) and...

The present study was carried out to estimate (co)variance components and genetic parameters for some productivity traits of Baluchi ewes. The data were collected during a 31 year period (1984-2014) at the experimental breeding station of Baluchi sheep, which is located in north-east of Mashhad, Iran. The analysis was based on 14030 records of lambs and 4371 records of ewes. Investigated traits...

background: rfamide-related peptide-3 (rfrp-3) inhibits gonadotropin releasing hormone (gnrh) and luteinizing hormone (lh) secretion in rats. this study evaluates the effects of litter size and suckling intensity on rfrp mrna expression in the dorsomedial hypothalamic nucleus (dmh) of rats. materials and methods: a total of 32 pregnant and 4 non-lactating ovariectomized (control group) sprague-...