This study was aimed to determine whether the presence of sexually stimulated rams by photoperiodic and melatonin treatments can advance the resumption of post-partum sexual activity in Mediterranean ewes lambing in January and weaned at the end of the breeding season at 41°N, in March. Rams were exposed to two months of long days (16 h light/day) and given three melatonin implants at the end o...

Two experiments were designed to determine the effects of duration of lactation and plane of nutrition on the reproductive performance of Finn x Dorset Horn ewes mated at a hormonally induced oestrus 9 weeks after lambing. In Exp. 1, ewes were mated on 4 December or 19 March and lactation was terminated at 35 or 15 days before mating or 7 or 35 days after mating. The fertility of ewes lactating...

Six experiments were conducted to determine the ability of exogenous estradiol-17/3 to increase numbers of sperm in the oviducts, uteri and cervices of inseminated estrous ewes. In a 2 x 3 factorial experiment, ewes were mated during either early or late estrus; ewes in each group were either not treated or were treated with estradiol by subcutaneous injection once, at 6 hr after mating (30 /ag...

Three-hour milk production measurements determined by machine milking at 3-d intervals throughout a 63-d lactation period were used to describe lactation curves for crossbred ewes lambing at 1 and 2 yr of age and rearing single and twin lambs. Age of ewe, type of rearing, and day of lactation affected (P < 0.05) milk production. Over the 63-d lactation, average daily milk production was 2.56 an...

Effects of number of lambs suckled and supplemental protein source on ewe performance were determined. Lactat ion performance of ewes nursing twin or triplet lambs was compared in Exp. 1 and 2. In Exp. 1, ewes giving birth to and nursing triplets produced 21% (P<.05) more milk/unit metabolic body weight, were 10% more efficient in the conversion o f feed to milk and produced 26% (P<.05) more kg...

Two experiments were conducted utilizing ewes to determine the effects of small diameter IUDs on fertility, lengths of estrous cycles and uterine histology. In both experiments, IUDs were inserted bilaterally at day 3 of the estrous cycle (estrus = day 0). The IUDs were single strands of nylon suture (.3 mm diameter) lying free in the uterine lumen except at a point of attachment near the utero...

Ovulation rate, serum hormone concentrations, follicular fluid (FFL) concentrations of steroids and IGF, IGF binding protein (IGFBP) activity in FFL, and follicular IGF-I and -II mRNA were compared during the follicular phase among five genotypes of ewes: Finn (F), Composite III (C), 1/2 Booroola Merino (B) x 1/2 F (B x F), 1/2 F x 1/2 C (F x C), 1/2 B x 1/2 C (B x C). Composite III ewes were a...

BACKGROUND Nearly 50% of U.S. women of child-bearing age are overweight or obese, conditions linked to offspring obesity and diabetes. METHODS Utilizing the sheep, females were fed a highly palatable diet at two levels of overfeeding designed to induce different levels of maternal body weight increase and adiposity at conception, and from conception to midgestation. Fetal growth and organ dev...

BACKGROUND Low food availability leading to reductions in Body Condition Score (BCS; 0 indicates emaciation and 5 obesity) in sheep often coincides with low temperatures associated with the onset of winter in New Zealand. The ability to adapt to reductions in environmental temperature may be impaired in animals with low BCS, in particular during pregnancy when metabolic demand is higher. Here w...

The primary selection objective in the South African Mutton Merino is meat production, while wool plays a secondary role. The Merino, on the other hand is selected for wool production. Respectively 20 and 23 of each genetic different type of ewes were used in a 15-week indoor study to quantify the influence of nutrient intake on certain production traits when fed at different levels of their re...