Three groups of ewe lambs born in May (experiment 1; n=211) or April (experiment 2; n=174) were used to evaluate the effects of selection line and induction of estrus on pregnancy rate. Experiment 1 was a single factor experiment with induction of estrus as the main effect. In early December, May-born Targhee (n=82) and Rambouillet x Targhee (n=129) ewes were randomly assigned within body weigh...

The reproductive efficiency of the entire sheep flock could be improved if ewe lambs go through puberty early and produce their first lamb at 1 year of age. The onset of puberty is linked to the attainment of critical body mass, and therefore we tested whether it would be influenced by genetic selection for growth rate or for rate of accumulation of muscle or fat. We studied 136 Merino ewe lamb...

introduction one of the animal breeding aims is increasing the economic efficiency. therefore, mating among selected animals in order to enhance economic efficiency should also supply variation in population for next generations’ selection. this study was performed to estimate performance in cross breed lambs resulting from crosses of shal, moghani, afshari and varamini rams with varamini ewes,...

Sheep are highly social domesticated animals that evolved to live in large and structured groups. As other group-living species, individuals differ the level of association they have with others, these associations often result lasting stable bonds. However, there substantial gaps our knowledge temporal dynamics sheep, how their bonds vary relation environmental changes. Here, we aimed assess r...

Total litter weight weaned at 120 d postpartum per ewe lambing is often believed to be a measure of range ewe productivity. Genetic correlations for litter weight weaned at 120 d with prolificacy, growth, and wool traits for Columbia, Polypay, Rambouillet, and Targhee sheep were estimated using REML with animal models. Observations per breed ranged from 5,140 to 7,083 for litter weight weaned, ...

Vaginoscopy allows for diagnostic evaluation and treatment of the vaginal vault. A laparoscopic surgical port device and rigid telescope were utilized for serial vaginoscopy in 8 healthy anesthetized ewes. Vaginoscopy examinations were performed in each ewe at days 1, 14, and 28. This technique was well-tolerated and facilitated carbon dioxide vaginal inflation, complete vaginal examination, id...

the aim of this survey was to evaluate the frequency of pregnant ewes slaughtered in khorram abadabattoir and estimation of their gestational age. over a period of five months in fall and winter, a totalnumber of 3046 uterine tracts were collected. pregnancy was detected in 56.50% of ewes, 52.36% and 4.13% of which carried singleton and twins, respectively. the highest frequency of pregnancy wa...

the aim of this study was identification of important factors and their effects on mortality of lori-bakhtiari lambs from birth to weaning. the data set used for statistical analysis were collected from 4991 lambs born between 1370 and 1384 in flock at lori-bakhtiari sheep breeding station. data was modeled using logistic regression. mortality variable as dependent and ewe weight at mating, ewe...