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 (...

The extent to which species' traits, behavior and habitat synergistically determine their response to extreme weather events (EWE) remains poorly understood. By quantifying bird and vegetation assemblages before and after the 2008 ice storm in China, combined with interspecific interactions and foraging behaviours, we disentangled whether storm influences avian reassembly directly via functiona...

Reproductive performance and body weights of four and five-year old crossbred ewes representing five combinations of Finnsheep (F), Dorset (D) and Rambouillet (R) breeding were evaluated when lambing in the summer Oune-July, 1976). The five breed combinations represented were 1f2D, 1f2R; %D, %R; %F, 1f2D, %R; %F, %D, 1f2Rand %F, 3f4R. Breeding effectiveness of purebred and crossbred rams of Ham...

in this study 71 head of conceiving ewe and their progeny (91 head) from the flock of lori-bakhtiari sheep (360 head), in sholi station were randomly selected to determine the relationship between the immunoglobulin (igg) concentration in the ewe's serum and colostrum, and lamb's serum. ewe blood sample, colostrum of ewe and blood of the lamb was taken 2 weeks before parturition, 1 to 8 hours a...

Developing effective selection programs for improving the performance of livestock requires taking the economical selection indices into account. The present study was performed for comparing four selection indices developed in Kermani sheep through simulated data. The relative importance of traits was determined based on the estimated economic values and consequently, the most beneficial trait...

productive and reproductive traits have great importance in international dairy cattle breeding objectives. production, reproduction (days open and calving interval) and pedigree data of iranian holstein dairy cattles were collected between 2002 and 2012 from 47 herds in isfahan province. the data set consisted of 30179 records from 18837 registered iranianholstein dairy cattles. single trait r...

The objective of this study was to test the hypothesis that a combination of induced estrus (IE) and melatonin (MEL) would increase reproductive performance in breeds characterized by late maturity more than either IE or MEL alone. Spring-born Columbia (C; n = 161; 188 to 222 d range of age at breeding; 49 to 80 kg range of BW at breeding) and Targhee (T; n = 166; 183 to 210 d range of age at b...

The seasonality of reproductive activity in the ewe in temperate latitudes is controlled by photoperiod. Its annual variations control the temporal organization of the sexual cycle by changing the activity of the gonadotrophic axis. Cyclic oestrous behaviour usually appears in the ewe at the end of summer or the beginning of autumn and finishes in winter or at the very beginning of spring. Seas...

Introduction Merino ewes are the backbone of the Australian sheep industry and this is likely to be the case for some time. Stocking rate will remain a key profit driver in Merino enterprises and to maintain or improve profitability producers will need to continually adapt their production systems to deal with even larger changes in feed supply between seasons and years. The reproductive perfor...