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 experiments were conducted to determine: (1) the direction of uterine contractions in Days 32 and 52 postpartum ewes (Experiment 1); (2) the effect of PGF(2alpha) on direction of uterine contractions (Experiment 2); and (3) the effect of PGF(2alpha) on fertility rates in Day 32 postpartum ewes (Experiment 3). In Experiment 1, non-lambing (>90 days postpartum) and lambing ewes (day of lamb...

In two experiments, 64 crossbred ewes that had lambed in September or January and had their lambs removed within 24 h after birth were assigned to four groups and given the following treatments: group 1 (16 ewes)-1 ml saline, im or iv on d 10 postpartum; group 2 (24 ewes)-150 microgram/gonadotropin releasing hormone (GnRH) in 1 ml saline, im or iv on d 10 postpartum; group 3 (16 ewes)-150 micro...

Twenty Polypay-sired ewes (Group P) and 14 Suffolk ewes (Group S) were bled at 48-h intervals for 10 d beginning on April 6, 1989, and the serum was assayed for progesterone to determine which ewes were anestrous; 9/20 Group P ewes were anestrous, compared with 14/14 Group S ewes (P less than .001). Catheters were placed into the jugular vein of anestrous ewes from both breed groups (eight of G...

Three experiments were conducted with ewes to determine the effects of pregnancy and(or) supplemental protein source on amino acid absorption and digestive criteria. In Exp. 1, four mated and five nonmated ewes fitted with abomasal and ileal cannulas were offered 272 g of cracked corn/d and ad libitum alfalfa hay (22% CP). Mated ewes absorbed greater quantities (P less than .10) and percentages...

A total of 399 crossbred ewes born in 2 yr were maintained either on irrigated or dryland hill pastures. The ewes were sired by North Country Cheviot, Dorset, Finnsheep or Romney rams mated to Suffolk or Columbia-type ewes. The crossbred ewes were mated to Hampshire rams throughout the study and had the opportunity for either 4 or 5 yr of production. Annual feed cost was calculated based upon e...

The present study evaluated the hypothesis that the effects of hypoxia on sheep pregnancies at high altitude (HA) are mediated by oxidative stress and that antioxidant vitamins may prevent these effects. Both HA native and newcomer ewes were maintained at an altitude of 3,589 m during mating and pregnancy. Control low altitude (LA) native ewes were maintained at sea level. Half of each group re...

The thyroid structural changes in pregnant ewes and their fetuses were investigated. Out of 100 pairs of thyroid glands collected from ewes and their fetuses at the local municipal abattoir in Ahvaz city of Khuzestan province, multiple lesions were seen in 59% and 21% of the thyroid glands of ewes and fetuses, respectively. Histologically, ninety nine lesions in the ewes and twenty two lesions...

Two experiments were conducted to examine effects of d-á-tocopherol (vitamin E) on colostrum immunoglobulin G (IgG) titers and preweaning lamb performance. Trial 1 consisted of 86 Suffolk ewes receiving either no vitamin E (control) or 1500 IU vitamin E on d-28 prepartum. From the 86 ewes, a subset of 25 ewes was randomly chosen for an intensive analysis of ewe serum and colostrum IgG and lamb ...

The objective of this experiment was to compare vaccination schedules for ewes and their lambs to raise antibody concentrations to epsilon-toxin of Clostridium perfringens, the causative agent of enterotoxemia. Half of 200 Finnsheep x Dorset ewes were vaccinated with C. perfringens type D toxoid vaccine 3 wk before lambing. Serum samples were obtained from 20 ewes that were to be vaccinated and...