Susceptibility to infection from nematode parasites in sheep is most pronounced in young animals and in periparturient ewes. The susceptibility of young animals is a consequence of an inability to develop effective acquired immune responses to nematode parasites. In the periparturient ewe, susceptibility arises from a temporary loss of acquired immunity. Loss of immunity is associated with a ri...

the present study was aimed to improve the reproductive performance of corriedale ewes by nutritional flushing. forty corriedale ewes were divided into four treatment groups (tc, t1, t2 and t3) with 10 ewes in each group (n=10). at the beginning of the breeding season extra feeding (flushing regime) was started for approximately 34 days such that two estrus cycles were covered. first group i.e....

In Exp. 1, 39 ewe lambs (initial BW 29 +/- .1 kg) were used in a 2 x 2 factorial arrangement with two breeds (Polypay and Targhee) and two diets (high-forage and high-grain) to examine the effects of restricting intake of a high-grain diet on onset of puberty and lamb performance. The experimental diets were fed from 13 to 40 wk of age. The high-forage diet was composed of 80% alfalfa cubes and...

Ewes from lines selected for high and low reproductive rate and a control line bred and selected randomly were endoscopically examined 3 to 5 d after breeding to determine ovulation rates in the fall of 1985, 1986 and 1987. Fertility (ewes lambing per ewe exposed), lambing rate (lambs born per ewe exposed) and litter size (lambs born per ewe lambing) were evaluated at lambing in the spring of e...

This study examined the effects of melatonin and level of nutrition on embryo yield during anestrous and breeding season. Adult Rasa Aragonesa ewes were assigned randomly to one of the four treatment groups in two experiments using a 2x2x2 factorial design. Individuals were treated (+MEL) or not treated (-MEL) with a subcutaneous implant of melatonin for 42d (Melovine, CEVA) and fed 1.5 (contro...

The "reproductive ground plan" hypothesis (RGPH) proposes that reproductive division of labour in social insects had its antecedents in the ancient gene regulatory networks that evolved to regulate the foraging and reproductive phases of their solitary ancestors. Thus, queens express traits that are characteristic of the reproductive phase of solitary insects, whereas workers express traits cha...

This study was carried out at the National Sheep Research Station in Elhuda, Sudan to investigate situation of female sheep conditions while gestation and consult some aspects associated pregnancy parameters others on live weight were collected, processed statistically tested addition variability consideration. Thus, changes its relationships for certain reproductive traits Shugor Dubasi subtyp...

Secondary sexual traits displayed by males and females may have evolved as a signal of individual quality. However, both individual quality and investment on producing or maintaining enhanced sexual traits change as individuals age. At the same time, the costs associated to produce sexual traits might be attenuated or increased if environmental conditions are benign or worse respectively. Accor...

The objective of this study was to examine the impact of polymorphisms in the acyl-CoA:diacylglycerol acyltransferase (DGAT1), leptin and growth hormone receptor genes on body energy (body condition score, total body energy content and cumulative effective energy balance) and blood metabolic traits (levels of beta-hydroxybutyrate, glucose and non-esterified fatty acids), measured once before th...