the aim of this study was to determine the effects of ecg, pgf2α and gnrh hormone on improvement of reproduction performance of cidr synchronized zandi ewes in breeding season. 500 ewes with age of 2.5-4 years and same nutritional condition were selected for this study and received cidr for 12 days. then these ewes were assigned to five equal groups. first group received no hormone (control gro...

Cumulative lifetime (five lamb crops) lamb production and wool production of 681 ewes were evaluated in this study. Lamb production and wool production from each ewe at the end of age 2, 3, 4, 5, and 6 yr were added to the previous year's production and analyzed within age of ewe. If a ewe failed to lamb, died, or was culled, it received a zero for that year and subsequent years. Main effects i...

Abrupt weaning, a usual management in sheep productive systems, may provoke behavioural and physiological responses indicative of stress in ewes and lambs. Progesterone (P4) has anxiolytic and sedative effects through the union of its metabolites that contain 3α-hydroxyl group to the γ-aminobutyricacidA receptor. Our first aim was to determine whether P4 administration reduces the behavioural a...

Anestrous ewes respond to the introduction of rams with either an ovulation within 2-3 days that may be followed by luteal phases of normal or short length, with delayed ovulations (5-6 days later), or with the luteinization of follicles. The aim of this work was to study the relationship between the growth status of the largest follicle present when rams are introduced and the type of ovarian ...

The effects of fat supplementation and weaning system on commercial milk yield and milk composition were determined on 129 East Friesian crossbred ewes. Prior to lambing, ewes were randomly assigned to one of two weaning systems. The DY1 system involved weaning of ewes from their lambs within 24 to 36 hr post-partum and then twice-daily machine milking. In the MIX system, ewes had access to the...

The objectives were to determine the effects of short-term feeding of a toxic endophyte (Neotyphodium coenophialum)-infected tall fescue seed (Festuca arundinacea, cultivar 'Kentucky 31') on fecal shedding and intestinal concentrations of Escherichia coli O157:H7 and the concentrations of prolactin, cortisol, and NEFA in experimentally inoculated ewes. Twelve ewes (mean BW = 46 +/- 2 kg) were f...

First cross Booroola Merino x Romney (B x R) ewes born in 1975, 1976, 1978 and 1979 were classified as being heterozygous (F+) or non carriers (++) for the Booroola fecundity gene. Their performance as hoggets (< 1 year of age) I and to six years of age (1975 and 1976 bornonly) was compared with contemporary Romney (R) ewes. As hoggets, the F+ ewes had ovulation rates about 0.5 higher than ++ B...

The effects of exogenous melatonin on reproductive performance of 737 Polypay and Polypay-cross ewes were evaluated during a late March and April breeding period. Different concentrations (2 or 10 mg) routes of administration (fed vs implanted) and durations of administration (20 or 40 d before breeding) were studied. Estrus was synchronized in all ewes using 60 mg medroxyprogesterone acetate (...

Thin ewes or very over-conditioned ewes and ewes carrying multiple pregnanciesare more likely to develop pregnancy toxemia (ketosis). Pregnancy toxemia is a metabolic disorder characterized by hypoglycemia and hyperketonemia resulting from incapacity of the ewes to maintain adequate energy balance (usually in the last 5-6 weeks).Available information about pregnancy toxemia focuses mainly on pa...

the aim of this study was to evaluate the effect of glycogenic diets supplemented with different poly unsaturated fatty acids on reproductive performance of iran black ewes in two different managing programs. ewes were allocated in two different groups; group a (n = 75) and group b (n = 25). ewes from group a were stopped from suckling followed by introducing to the rams on days 80 and 90, resp...