Two, 8-month-old Rambouillet half-sister ewes with signs of visual loss and decreased mentation were examined. Ewe No. 1 was necropsied at 10 months of age, and after being held under observation for a further 6 months, ewe No. 2 was necropsied at 16 months of age. At that time, the ewe was blind and severely depressed. Both ewes had deposition of an autofluorescent lipopigment, identified as c...

The incidence of positive CMT, indicative of subclinical mastitis, was studied in a flock of purebred Targhee ewes from four selection lines. The incidence of positive CMT was found to be random at lambing with respect to age and line of ewe, number of lambs born and weaned and sex of lambs, but at docking (3 to 7 weeks after lambing) increased with increasing age of ewe and number of lambs bor...

Forty-eight crossbred ewes were subjected to heat stress of short or long duration during the last third of gestation in a completely randomized design to determine the effects of maternal heat stress on lamb birth weight, lamb conformation and subsequent preweaning growth rate. Ewe treatments were spring range pasture, confinement on slotted floors in a heated room maintained between 28 to 38 ...

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 ...

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...

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, ...