Effect of supplementary feeding on the gastrointestinal strongylid eggs shedding in grazing pregnant merino ewes

9 pages, 3 figures, 1 table.Sixty Merino ewes during 140 days of pregnancy were naturaliy inf-ected by strongylids a t grazing, but 30 animals were provided a barley supplement furthermore (400 grams per head day-t). Faecal samples were collected every 20 days for analysis and by means of faecal cultures the genera of strongylids present were identified. Body weight and body condition scores were also recorded every 10 days. Results showed that liveweight and body condition scores were higher in supplemented group than unsupplemented one during study. Unsupplemented ewes showed the higher strongylid eggs elimination during early pregnancy and periparturient rise in late pregnancy; and during whole experiment showed higher infection percentages than supplement fed group. However, supplemented ewes showed from 100 days ofpregnancy higher values ofstrongylid eggs output. An increase in parasite establishment resistance of supplemented ewes is suggested and epidemiological implications will be discussed.This work was supported by an European union project (AIR CT92-0646).Peer reviewe

Genetic relationships between the mutations spade and Stemopleural and the wingless gene in Drosophila development

AbstractInDrosophila melanogaster,there are cases in which gene products contributing to the same developmental event may derive from closely adjacent transcription units and may even sharecis-regulatory sequences. Correct recognition of such genomic organization is central to an understanding of developmental mechanisms. The adult phenotypes of combinations between the mutationsspade, Sternopleural,andwinglesssuggest that they are lesions in functionally related genes within the same chromosomal region.winglessmutations fail to complement the recessive mutationspade.Thespademutation, as previously shown, behaves as a lesion in a regulatory site ofwingless,sited 5′ to the transcription unit, and is concerned with particular postembryonic functions ofwingless.While showingwingless-like phenotypes in combination withSternopleural,even lethal alleles ofwinglesscomplement the recessive lethality ofSternopleuralalleles. Mutations inSternopleuralincrease the severity ofwinglessphenotypes in manywingless-dependent processes during postembryonic development, and this interaction can occur when the only functional copies ofSporwgare located in either opposing chromosomes or the same chromosome. This is inconsistent with previous attempts to defineSpas a regulatory allele ofwgand explain the phenotypes that result from combinations ofSpandwgby means of transvection. We have analyzed a new EMS-induced allele ofSternopleuralthat is more severe than the original allele, which also argues forSpbeing a separate, mutable genetic locus rather than a regulatory allele ofwg.Finally, we have a revertant ofSternopleural(SpRv1) that behaves as a genetic null allele ofwg,but causes ventral-to-dorsal transformations in combination withwgP,which is not observed in combinations ofwgnull alleles withwgP.BecausewgPis the result of an inversion and because inversions inhibit transvection, the increased severity observed inSpRv1/wgPin comparison towgnull/SpRv1animals cannot be explained by an absence of transvection. Therefore, the twoSternopleuralmutations most reasonably define an independent gene located 3′ to thewinglessgene and having strong functional synergism with it

Effect of long-term supplementation on animal performance of grazing ewes

Feeding management in grazing systems usually involves supplementary feeding during critical periods to increase the intake and prevent high losses of body reserves (Gunn et al., 1992; Castro et al., 1994). However, in grazing systems the response to additional fed can be erratic or inconsistent at medium or long terms. Therefore it is necessary a better understanding of the effeets of supplementation to define feeding strategies. The present experiment was designed to examine the effect of supplementation of grazing ewes duríng two consecutive production cycles on animal performance.Peer reviewe