Reproductive performance of three fat-tailed breeds of sheep mated to native,Corriedale and Targhee rams

Summary Reproduction and lamb production of three fat-tailed, carpet-wool Iranian breeds of sheep; Karakul (130 ewes), Mehraban (103) and Baluchi (119) were studied. The ewes were mated either as purebreds or with Corriedale or Targhee rams. The overall least-squares means for ewes mated (showed oestrus) or ewes exposed, ewes lambed or ewes mated, lambs born of ewes lambing (prolificacy), lambs born alive of total lambs born, lambs weaned of live lambs born, lambs weaned (75 days of age) of ewes mated, kg lamb weaned per ewe mated and kg lamb weaned per 100 kg ewe mated were 98.3%, 93.5%, 103.1%, 94.9%, 97.8%, 90.0%, 18.2 kg and 38.4 kg respectively. The native breeds were not different for any of the traits studied except for prolificacy which was higher in Mehraban than in Karakul. Purebred matings did not differ from the crossbred matings for any of the traits concerning the number of lambs but crossbreeding improved kg lamb weaned per ewe mated (9.2%, P=0.08) and kg lamb weaned per 100 kg ewe mated (10.0%, P<0.05). Among the three native breeds Karakul showed the largest improvement when crossed with the exotic rams for the traits concerning kg lambs weaned. Corriedale and Targhee rams had similar effects on all the traits studied. A lower percentage of virgin ewes showed oestrus, had a lower twinning rate and productivity compared with the mature ones. Sex was not a significant source of variation in lamb livability.

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Desempeño Reproductivo De Tres Razas Cola Gruesa De Ovejas Apareadas Con Moruecos Nativos, Corridale Y Targhee

Resumen Se estudiaron la reproducción y producción de corderos iraníes de tres razas fat-tailed (Cola gruesa o grasosa) productores de lana para carpetas: Karakul (130 ovejas), Mehraban (103) y Baluchi (119). Las ovejas fueron apareadas como puras, o con moruecos Corridale o Targhee. Las medias mínimas cuadradas para ovejas apareadas (que mostraron estro) de ovejas expuestas, ovejas paridas de ovejas apareadas, corderos nacidos de ovejas paridas (prolificidad), corderos nacidos vivos del total de corderos nacidos, corderos destetados de corderos nacidos vivos, corderos destetados (75 días de edad) de ovejas apareadas, kg de cordero destetado por oveja apareada y kg de cordero destetado por 100 kg de oveja apareada, fueron: 98.3%, 93.5%, 103.1%, 94.9%, 97.8%, 90.0%, 18.2 kg y 38.4 kg respectivamente. Las razas nativas no fueron diferentes en ninguna de las características estudiadas, excepto por le prolificidad la cual fue mayor en Mehraban, que en Karakul. El apareamiento de razas puras, no difirió de los apareamientos cruzados para cualquiera de las características estudiadas concernientes con el número de corderos, pero el cruzamiento mejoró los kg. de cordero destetado por oveja apareada (9.2%,p<0.08) y kg de cordero destetado por 100 kg de oveja apareada (10.0%,P<0.05). De las tres razas nativas, la Karakul fue superior cuando se cruzó con las razas exóticas en lo concerniente a las características kg de cordero destetado. Las razas Corriedale y Targhee tuvieron efectos similares en todas las características estudiadas. Un bajo porcentaje de ovejas vírgenes ciclaron regularmente, tuvieron un porcentaje bajo de mellizos y productividad en general, comparada con las ovejas maduras. El sexo no fue una fuente significativa de variabilidad, en la supervivencia de los corderos.

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Performances De Reproduction De Trois Races De Moutons À Queue Grasse Accouplées À Des Locales, Corriedale Et Targhee

Résumé La reproduction et la production d'agneaux de 3 races iranienes à queue grasse élevées pour la production de laine à tapis: karakul (130 brebis), Mehraban (103) et Baluchi (119) furent étudiées; Les brebis furent accouplées soit en race pure soit avec des béliers Corriedale ou Targhee; Les moyennes estimées par la méthode des moindres carrés de l'ensemble des brebis accouplées (oestrus visible) par rapport aux brebis exposées; des brebis agnelant par rapport aux brebis accouplées, des agneaux nés par rapport aux brebis agnelant (prolificité); des agneaux nés vivants sur les nés totaux, des agneaux sevrés sur les nés vivants, des agneaux sevrés par brebis accouplée, et du kg d'agneau sevré par 100 kg de brebis accouplées étaient 98,3%; 93,5%, 103,1%, 94,9%, 97,8%, 90,0%, 18; 2 kg et 38,4 kg respectivement. Les races natives n'étaient pas différentes pour les autres caractères étudiés excepté pour la prolificité qui était plus élevée en Mehraban qu'en Karakul. Les accouplements en race pure ne différaient pas des croisements pour tous les caractères concernant le nombre d'agneaux mais le croisement améliorait les kg d'agneaux sevrés par 100 kg de brebis accouplée (9,2%P=0,08) et les kg sevrés par 100 kg de brebis accouplée (10,0%P<0,05). Parmi les 3 races natives, la Karakul montrait l'amélioration la plus grande lorsque croisée avec les béliers exotiques pour les caractères concernant les kg d'agneaux sevrés. Les béliers Corriedale et Targhee avaient des effets similaires sur tous les caractères étudiés. Un plus faible pourcentage de brebis vierges à oestrus visible, avait un plus faible taux de jumeaux et de productivité comparé aux brebis matures. Le sexe n'était pas une source significative de variation dans la viabilité des agneaux.

     

Comparative infectivity for axenic and specific-pathogen-free chickens of O2 Escherichia coli strains with or without virulence factors

Adhesion to epithelial respiratory cells, iron acquisition, and production of K1 polysaccharide capsules have been proposed as potential virulence factors of avian Escherichia coli. These factors were studied by inoculating groups of axenic or specific-pathogen-free (SPF) chickens intratracheally with O2 E. coli strains after previous challenge with a wild strain of infectious bronchitis virus (IBV). In all experiments, the association between IBV and an E. coli strain endowed with the three virulence factors previously mentioned resulted in the most severe pathological effects, as measured by mortality, weight gains, lesions, and reisolation of E. coli from internal organs. An E. coli strain devoid of virulence factors was able only to induce mild pathological effects restricted to the respiratory tract when combined with IBV. Both E. coli strains were more invasive in axenic chickens than in SPF chickens. These results confirm the probable involvement of the three factors studied in the pathogenic properties of avian E. coli. This model can be used to assess the role of virulence factors, by comparing pairs of positive and negative isogenic strains.     

Soil mixing in the East Anglian fens

Abstract. Experiments were started in 1967 to investigate the effects of soil mixing on fen peat soil. Peaty topsoil was mixed with mineral subsoil to a maximum depth of 80 cm at two sites, one with a clay subsoil, the other sand. Mixing was done on a commercial scale with a range of implements. After initial increases, yields of arable crops on both mixed soils were subsequently similar to those on unmixed soil. Residual herbicide activity was enhanced on mixed soils, and evidence of peat conservation was obtained at one site. The practice has not been taken up commercially because of the high capital cost of mixing and lack of serious problems which had been predicted following peat wastage.     

Distribution of Cytochrome P450-side Chain Cleavage in the Theca Interna Layers of Bovine Small Antral and Cystic Follicles

Cystic follicle is anovulatory follicular structure that is caused by an endocrine imbalance. The activity of cytochrome P450‐side chain cleavage (P450scc) is essential for the initiation of steroidogenesis in the follicle. The present study was designed to compare the frequency of cells containing P450scc between healthy and atretic small antral follicles, and among several types (I, II and III, classified based on the presence of granulosa layer) of cystic follicles. Paraffin sections of healthy (2–5 mm in diameter), atretic (2–5 mm) and cystic follicles (>25 mm) were immunohistochemically stained with rabbit polyclonal antibody to bovine P450scc. The P450scc‐positive cells were counted in four different regions of the follicles from the apical to the basal side. In small antral follicles and cystic follicles, P450scc‐positive cells were localized in the theca interna layers but not granulosa layers. The P450scc‐positive cell populations decreased in the late atretic follicles compared with the early and advanced atretic follicles at all the regions of follicle. Type III cystic follicles showed significantly lower frequencies of P450scc‐positive cells than those in the types I and II cystic follicles. These results suggest that in both small and cystic follicles in cows, total loss of granulosa cells may be associated with the reduction of frequency of P450scc‐positive cells in theca interna layer.