Experiments were designed to localize the central sites of action of melatonin involved in the control of seasonal reproduction. Ewes were exposed to long days and received microimplants of melatonin in the preoptic area (n = 9), anterior hypothalamus (n = 4), dorsolateral hypothalamus (n = 4), or mediobasal hypothalamus (n = 12). The effects of implants were determined by comparison with contr...

Newborn lambs depend on their dams for passive transfer of immunoglobulins, primarily IgG, for protection from harmful pathogens until their own immunological defenses have developed. Previous studies have suggested that supplementation with Se results in a modest increase in IgG concentration in serum of newborn calves and lambs. To evaluate the effect of the Se source and supplementation rate...

Milk production and lamb growth were characterized in 118 multiparous, 3- to 7-yr-old Rambouillet, Columbia, Polypay, and Suffolk ewes under spring sage range and high mountain meadow grazing from 28 to 98 d postpartum. Daily milk yield as measured by the lamb suckling weight differential technique did not differ (P greater than .05) among breeds, although milk production of Suffolk ewes tended...

The aim of this trial was to evaluate the effectiveness (fertility and lambing) of priming with a single injection of progesterone plus PMSG in anovulatory lactating Sarda ewes subjected to the ram effect (RE) in spring. Thirty ewes (P4 group) were i.m. injected with 30 mg progesterone and 500 IU PMSG 36 h before ram introduction (d 0). This treatment was compared to a 12-day treatment with flu...

Our objective for this study was to determine the pattern of nutrient flux across the portal-drained viscera (PDV) and liver in ewes with varying numbers of fetuses. Catheters were placed in the hepatic portal vein, a branch of the hepatic vein, a mesenteric vein, and the abdominal aorta of ewes. Blood flow and net nutrient release across the PDV and liver were determined before exposure to ram...

The studies were conducted on thirty ewes of two genotypes. For each genotype the ewes were divided into two groups: stabling and pasture. The objective of the investigation was to determine the influence of maintenance system on chosen morphological and biochemical blood indicators as well as the parameters of reproduction traits of sheep. In the first year of the studies the ewes of both grou...

In pregnant sheep, maternal:fetal exchange occurs across placentomes composed of placental cotyledonary and uterine caruncular tissues. Recently, we reported that fetal weights of obese (OB) ewes [fed a diet of 150% of National Research Council (NRC) recommendations] were approximately 30% greater than those of control (C) ewes (fed a diet 100% of NRC recommendations) at midgestation (MG), but ...

Two accelerated lambing systems, Morlam using Morlam sheep (USDA, Beltsville 1966 to 1975) and Camal using Dorset ewes (Cornell 1978 to 1981), were evaluated for first lambing ages, interlambing intervals and conception probabilities. Morlam ewes were continuously exposed to rams over the year, while Camal Dorset ewes were exposed every other month. Morlam lambs were mated as early as 367 d of ...

I . The use of deuterium oxide dilution to obtain an indirect estimate of body water in pregnant ewes was examined and the value of such an estimate in predicting body fat was investigated. 2. Deuterium oxide was infused intravenously into fourteen twin-bearing Blackface ewes and blood samples were taken 6-7 h later. The animals were subsequently slaughtered. 3. Deuterium oxide concentration wa...

Lamb production was measured over an 18 month period from 30 Javanese thintail (JTT) and 30 Border Leicester x Merino (BLM) ewes run continually with rams of several breeds. The study was carried out in West Java, Indonesia. One hundred and forty-eight lambs were born to JTT and BLM ewes respectively, the difference being associated with both a larger number of lambings and a higher incidence o...