Intrauterine growth restriction (IUGR) is a major health problem worldwide that currently lacks an effective therapeutic solution. This study was conducted with an ovine IUGR model to test the hypothesis that parenteral administration of l-arginine (Arg) is effective in enhancing fetal growth. Beginning on d 28 of gestation, ewes were fed a diet providing 100% (control-fed) or 50% (underfed) of...

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 ...

Two-hundred-fifty-six crossbred and Targhee ewes which lambed in February and March were randomly assigned to a 38or 73-day postpartum weaning group and within weaning group to a control, an 8or a 16-day progestogen treatment. Treatment was an intravaginal progestogen pessary for 7 days after weaning or for 15 days beginning 8 days before weaning with a 10 mg injection of progesterone on the da...

In Préalpes de Sud ewes after an autumn lambing, the mean post-partum interval to first LH surge was 10 +/- 1 days and 17 +/- 1 days for non-suckling and suckling ewes, respectively. Post-partum interval to first luteal phase, estimated from plasma progesterone concentrations, was similar in non-suckling and suckling ewes (27 +/- 1 days and 28 +/- 5 days, respectively). Interval to first oestru...

In sheep industry, pregnancy rate after artificial insemination (AI) declines due to the complex anatomy of the cervix in ewes, such that it might prevent effective intrauterine insemination. At estrus, cervical relaxation occurs to some degree in ewes, which is regulated by the changes in the levels of reproductive hormones. This study aimed to evaluate the effects of estradiol and intravenous...

Thirty 6-yr-old Targhee ewes were randomly allotted to one of five supplemental treatments to evaluate supplementation effects on liver and fecal Zn and Cu concentrations and serum alkaline phosphatase activity: 1) control, 2) Zn complex, 3) Zn and Cu (ZnCu) complex, 4) Zn sulfate, and 5) ZnCu sulfates. Supplements were administered daily in gelatin capsules for 56 d. Liver biopsies and serum s...

The objectives of this study were to evaluate intestinal cellularity and vascularity in mature ewes in response to dietary restriction and pregnancy status and to quantify the response of these variables to increased nutrient demand of fetal growth. In Exp. 1, 28 mature Dorset x crossbred white-faced ewes (61.6+/-1.8 kg initial BW) were fed a pelleted, forage-based diet. Treatments were arrange...

We conducted field and laboratory experiments to evaluate whether treating pregnant bighorn ewes with a combination of an experimental Pasteurella trehalosi and Mannheimia haemolytica (formerly P. haemolytica) vaccine and a commercially-available bovine P. multocida and M. haemolytica vaccine would increase lamb survival following a pneumonia epidemic. Three free-ranging bighorn herds affected ...

During pregnancy, plasma ACTH and cortisol are chronically increased; this appears to occur through a reset of hypothalamo-pituitary-adrenal (HPA) activity. We have hypothesized that differences in mineralocorticoid receptor activity in pregnancy may alter feedback inhibition of the HPA axis. We tested the effect of MR antagonism in pregnant and nonpregnant ewes infused for 4 h with saline or t...