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 ovaries of 3 groups of Merino ewes were examined for corpora lutea by laparoscopy every 17 days between 28.3.74 and 16.6.75. During the 1974 breeding season the mean body weight of the ewes was maintained at 37 kg. Between the 1974 and -1975 breeding seasons the nutrition of the ewes was varied to give groups of ewes with mean body weights of 37, 41 and 46 kg; groups of ewes of low, medium ...

The ToxChip, a DNA microarray chip, allows the monitoring of the expression levels of thousands of different genes at a time, thereby condensing months of painstaking laboratory tasks into a day's work. For toxicology researchers in particular, this tool is important because it promises a more effective way to identify environmental hazards and their effects on DNA. The ToxChip, developed by NI...

The effect of level of dietary energy and protein intake on reproductive performance was studied in 110 Finn-cross ewe lambs and in 404 Finn-cross yearling ewes during late gestation. Nitrogen metabolism was studied in 26 ewe lambs and 23 yearling ewes. Increasing digestible energy and crude protein intake for ewe lambs and yearling ewes during late gestation increased (P<.05) ewe average daily...

Pregnancy is characterized by increased plasma adrenocorticotropic hormone (ACTH) and cortisol. Studies suggest that progesterone acts as an antagonist at mineralocorticoid receptors. Therefore, we tested the hypothesis that chronic progesterone, produced by treatment of nonpregnant ewes or during pregnancy, will result in increased plasma ACTH relative to the plasma cortisol concentrations. We...

Two commercially available progestogen products for cattle, melengestrol acetate (MGA) and norgestomet (SMB), were evaluated for their ability to induce synchronized estrus in anovulatory ewes. Seasonally anestrous ewes (n = 232) were randomly assigned to one of seven treatments: 1) control (C); 2) MGA only (OMGA; .3 mg of MGA/d); 3) MGA+zeranol (RMGA; 2.5 mg of zeranol); 4) MGA+PG-600 (PMGA; 4...

During the last trimester of pregnancy single and twin-bearing ewes were fed chopped oat hay ad libitum and supplements (300 g/day) of cottonseed meal (CSM) (T1) or barley grain plus urea and sodium sulfate (Bar+N+S) (T2), or CSM and oat hay restricted to the level consumed by the T2 ewes (T3). T1 ewes consumed 47% more hay and approximately 13% more digestible organic matter than T2 ewes. T1 e...

Thirty-nine multiparous ewes (19 Pelibuey and 20 Romanov × Pelibuey) treated with fluorogestone acetate impregnated intravaginal sponges were used to evaluate the effects of low pregnant mare serum gonadotropin (PMSG) doses and genotype on their reproductive efficiency under heat stress conditions. The sponge treatment lasted for 12 days, and 24 h before sponge removal, ewes of each genotype we...

These studies test the hypothesis that pregnancy alters the feedback effects of cortisol on stimulated ACTH secretion. Ewes were sham-operated (Sham), or adrenalectomized (ADX) at approximately 108 days gestation and replaced with aldosterone (3 microg x kg(-1) x day(-1)) and with cortisol at either of two doses (ADX + 0.6 and ADX + 1 mg x kg(-1) x day(-1)); ewes were studied during pregnancy a...

St. Croix White hair sheep ewes were used to evaluate the effect of supplemental nutrition prior to breeding during the dry and wet seasons on St. Croix. Beginning 21 d prior to breeding ewes were fed supplement in addition to grazing guineagrass pasture (FEED). Other ewes in the flock grazed pasture only (CONTROL). This study was conducted during the dry (June and July) and wet seasons (Octobe...