In order to determine the efficacy of melatonin implants in initiating the lambing season and improving reproductive efficiency in sheep, ewes (n= 1932) from three breeds (Rasa Aragonesa, Assaf and Merino) received melatonin implants (Group M) every 45 days from the winter solstice (1 January and 15 February—winter; 1 April and 15 May—spring) on 12 commercial farms. The other group of ewes (n= ...

Breeding ewes to lamb at 1 yr of age can improve profitability for some production systems. The first objective of this study was to evaluate the effect of age and weight at breeding and total postweaning weight gain on reproductive performance of ewe lambs. The second objective was to compare the effects of weight and age variables in four major sheep breeds (Columbia, Polypay, Rambouillet, an...

The objective of the research was to evaluate effects increasing dietary Zn sulfate concentration for primiparous gestating ewes on subsequent milk SCC, intramammary microbial identifications, and fatty acid composition. Commercial white-face (WF; n = 27) black-face (BF; 24) (age ≈18 mo; BW 87.48 ± 8.37 kg) were sorted into breed-type groups within ranked by BW, then, they randomly divided 3 su...

Sheep production systems need to become more carbon efficient meet growing public demands on climate change. Some of the ways postulated achieve this is implement new technologies and management strategies such as precision livestock farming (PLF), increased use high genetic merit animals with estimated breeding values through artificial insemination (AI) where practical, prolific breeds. Howev...

BACKGROUND Housing sheep in insulated, warm buildings, which is common in Norway, involves high buildings costs, but has not been reported to improve health and performance. Few studies have dealt with the association between housing and management and reproductive performance.Data on housing and management during the indoor period from a questionnaire were merged with herd level data from the ...

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...

Rams with strong libido and desirable semen characteristics can provide more insemination doses per ejaculate and produce more progeny, improving population genetic linkage to improve the accuracy of EBV. The objective of this study was to determine if teasing rams, either by sight and smell alone (Exp. 1), or physical contact (Exp. 2), could improve libido and semen quality of rams. In Exp. 1,...

involved in choosing appropriate criteria and procedures for problem~ ses of breed and mating system evaluation experiments in sheep are. nom lC ana iiterature is rev1ewed of expenments 1n Wh1Ch blOlog1cal or econom1C scn bed . has been investigated. The .range in relative economic merit from the lCl ency the best group in an expenment tYP1cally 1S from 100 to 120, w1th rest to 140 not uncommon...

A study was undertaken to compare the longevity and lifetime lamb output of purebred Scottish Blackface (BF) ewes with a range of crossbred genotypes from Scottish BF dams. For up to five successive breeding seasons, 1143 Scottish BF, Swaledale × BF (SW × BF), North Country Cheviot × BF (CH × BF), Lleyn × BF (LL × BF) and Texel × BF (T × BF) ewes were mated to a range of sire breeds on six hill...

The objective of this study was to investigate the influence meteorological and other factors on quality quantity milk Spanish Churra sheep breed, based an analysis 359,808 controls from 9,904 ewes 15 farms in 8 years. Daily yield (DMY), fat, protein, lactose (%), somatic cell count (SCC) data were obtained monthly alternating controls. Mean, maximum, minimum temperatures (T) (°C), mean relati...