To determine similarities and differences between nonsuperovulated and superovulated ewe models, data collected from several experiments (1989 through 2005) were analyzed. Mature non-pregnant non-superovulated (n = 91) or superovulated (n = 299) Western range-type ewes were used for evaluation of luteal function. To induce superovulation, ewes were injected twice daily with FSH on days 13 to 15...

Range ewes are commonly evaluated for milking ability by producers to determine the ewe's ability to rear lamb(s). The U.S. Sheep Experiment Station has subjectively scored (low, average, high) a ewe's milking ability within 24 h of lambing for many years. The relationship of subjective milk scores with lamb production was investigated using lambing records of Columbia (n = 1,731), Polypay (n =...

St. Croix White and Barbados Blackbelly hair sheep ewes were used to evaluate the effect of supplemental nutrition around lambing on ewe and lamb performance during the wet season on St. Croix. Beginning 14 d prior to expected day of lambing (day 0) and for 21 d postpartum, 11 ewes were fed a pelleted complete ration (17% crude protein) at a level to provide 150% of the nutrient requirements, i...

A new mutation in the bone morphogenetic protein 15 (BMP15) gene (FecX allele) causing increased prolificacy in heterozygous (R+) and sterility in homozygous ewes has been recently described in Rasa Aragonesa, a low-prolificacy Mediterranean breed. The current study determined, first, the effect of this polymorphism on natural and eCG-induced ovulation rate (OR) and the effect of eCG dose on re...

Ewes bearing more than 1 fetus are more susceptible to pregnancy toxemia than those with a single fetus. Crossbreeding programs in Israel increased the occurrences of ewes bearing more than 2 fetuses; therefore, the aim was to assess the exacerbation in the metabolic status of ewes pregnant with several fetuses. Fifty ewes, genetically developed to achieve multiple-fetus pregnancies, were monit...

Selenium is an essential micronutrient in sheep, and deficiency can limit lamb growth and survival. To evaluate how different chemical forms of Se administered to mature ewes at comparative dosages affect ewe and progeny performance, 240 ewes were divided into 8 treatment groups (n = 30 each) and drenched weekly with no Se; at the maximum FDA-allowed concentration with inorganic Na-selenite or ...

Counts were made of the numbers of spermatozoa in the Fallopian tubes of ewes 24 hr after mating or after insemination with either sheep or goat semen. Spermatozoa were recovered from all five mated ewes (10/10 tubes), from all eight ewes inseminated with sheep semen (13/15 tubes) and from four of eight ewes inseminated with goat semen (7/16 tubes). The calculated mean numbers of spermatozoa pe...

The effect of ram percentage on the fertility of maiden ewes joined in autumn was examined on ten properties in New South Wales. On four of these properties a group of maiden ewes was joined to one per cent of rams and another group to three per cent. On another two properties the design was similar, but a third group containing maiden and mature ewes was also joined to one per cent of rams. On...

The efficacy of two doses of progesterone (P4), i.e. 350 and 300mg was evaluated in acycling crossbred ewes (50) during the autumn breeding season. Ewes were treated with intravaginal progesterone sponges with either 350mg or 300mg for 12 days. At standing estrus, ewes were hand mated (three cycles). Progesterone (350mg) gave a better (P<0.05) estrus response (75%), compared to 300mg dose (42%)...

Most North Dakota sheep production scenarios require substantially more resources, such as feed, labor, and facilities during late gestation and lactation. Early identification of pregnancy and pregnancy rate in sheep provides managers several options to increase flock productivity. First, removal of non-pregnant ewes can increase available resources for pregnant ewes. Second, identification of...