A large sheep dataset including ewe and progeny records from 1982 through to 2006 was used in the present study. The data included the variables: sex of lamb, birth rank, weaning weight, year born and dam and sire. The aim was to firstly, determine if the age of the ewe’s dam, or the birth rank of the ewe affected her lifetime performance and secondly, to determine in twin-born lambs if the sex...

BACKGROUND Multiple births occur frequently in some Iranian sheep breeds, while infertility scarcely occurs. Mutation detection in major fecundity genes has been explored in most of Iranian sheep flocks over the last decade. However, previously reported single nucleotide polymorphisms (SNPs) for bone morphogenetic protein receptor-(BMPR)-1B and growth differentiation factor ) GDF9( known to aff...

the fecundity in sheep has been much interested for producers due to its economical importance. growth differentiation factor 9 (gdf9) is an autosomal gene with over dominance effect for twosingle nucleotide polymorphisms(snps), which resulted in sterility in homozygote mutant ewes and additive effect for three snps, without showing sterility event. in the present study, dna was extracted from ...

Effects of Dorset, Finnsheep, Romanov, Texel, and Montadale breeds for performance as sires were estimated in the initial phase of a comprehensive evaluation of these breeds as contributors to sheep crossbreeding systems. Objectives were to evaluate the effects of ram breed, ewe breed, season of mating, and two-way interactions. Rams from the five breeds were single-sire-mated with ewes from tw...

Lamb's birth weight and litter weight were found to be related to ewe weight. Deviations from generally applicable formulae indicated an interaction between the genotype of the lamb and the maternal environment, as suggested in egg transfer experiments. Land's (1977) hypothesis on the spare conceptus capacity, when comparing large and small breeds within a species, with respect to prolificacy, ...

Reproductive traits from 7642 ewes were recorded from 1975 to 1983. The ewes were of five breeds (Dorset (D), Finnsheep (F), Rambouillet (R), Suffolk (S) and Targhee (T)) and two composite lines [C1 (1=2F þ 1=4R þ 1=4D) and C2 (1=2F þ 1=4S þ 1=4T)]. Genetic parameters were estimated for six basic and seven composite traits. The basic traits were conception rate (CR), total number of lamb born (...

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 one of the most important sources of the red meat in iran is the meat produced from sheep. increasing lamb per ewe considered as a strategy for improving the efficiency for sheep production, although reproduction traits have low heritability. several genes associated with reproduction were investigated in the recent years. the bmp 15 gene and its paralog gdf 9 and receptor, bmpr-ib...

Reproductive performance of four, five and six-year old crossbred ewes representing six combinations ofFinnsheep (F), Dorset (D), Rambouillet (R), and White Face Western (WFW) breeding were evaluated when lambing in the winter (February-March, 1977) and in the fall (October-November, 1977). The six breed combinations represented were 3fsF, 5fsWFW; %F, 1f2D, %R; %F, %D, 1f2R; %F, %R; 1f2D, 1f2R;...

A full termed local ewe with the history of continuous straining with labored breathing for last 24 hours was presented. The animal was disinclined to move with tense and round abdomen which developed rapidly during last two weeks. Caesarean section revealed hydrallantois accompanied by multiple fetal congenital abnormalities. The ewe was under observation for four weeks. Metritis developed 12 ...