Rendimiento del MOET aplicado al programa de selección de la Rasa Aragonesa de UPRA-Grupo Pastores

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Preliminary results of mastitis control program in meat sheep herds of rasa aragonesa breed

5 páginas, 3 figuras.-- Trabajo presentado al XXXVII Congreso de la Sociedad Española de Ovinotecnia y Caprinotecnia (Ciudad Real, España, 19 al 21 de septiembre del 2012).[EN] From previously established data regarding the prevalence (44%) and economic importance (12-42€/affected sheep) of mastitis in Rasa Aragonesa sheep, this study shows the results of a program for the control of mastitis applied in 64 flocks of this breed specialized meat production. This program is based on the application of preventive measures in the general management of the flock (control of orphan lambs, treatment of acute mastitis, improvement of hygiene in the milking and weaning ewes, prevention of diseases, and any predisposing factor, which could affect the mammary gland) and specific management over the weaning period (mammary gland palpation and culling of those sheep showing irreversible chronic lesions, application of treatments and dried-off procedure). The results from this program are showed based on the evolution of the intramammary infections and the analysis of the economic repercussions according to the rates of lamb mortality and average daily gain until weaning (45 days). This results show the costeffectiveness of the measures established under this program.[ES]Establecidas previamente la prevalencia (44%) y repercusiones económicas de las mamitis en ovejas Rasa aragonesa (12-24€/ovejas con infección intramamaria) en este trabajo se presentan los resultados de un programa de control de mamitis en 64 rebaños de ovino de carne de esta raza. El programa de control de mamitis propuesto, se basa en la implantación de prácticas preventivas relacionadas con el manejo general (control de corderos robadores, pautas a seguir ante las mamitis agudas, mejora de la higiene de los lotes de lactación y destete, prevención de enfermedades y causas predisponentes que lesionan la mama) y prácticas de secado/destete (palpación mamaria y eliminación de ovejas con lesiones crónicas irreversibles, manejo del secado y aplicación del tratamiento). Se exponen los resultados del Programa, basados en la evolución de la infección intramamaria y el estudio de repercusiones económicas con los indicadores de la evolución de la mortalidad de los corderos y de la ganancia media diaria de los mismos desde su nacimiento hasta el destete a los 45 días, que ponen de manifiesto la eficacia y rentabilidad de las medidas integradas en el mismo.Peer reviewe

La raza ovina ansotana: historia y situación actual

Resumen de la comunicación presentada al III Congreso Ibérico sobre Recursos Genéticos Animale

Effect of the FecXR polymorphism in the bone morphogenetic protein 15 gene on natural or equine chorionic gonadotropin-induced ovulation rate and litter size in Rasa Aragonesa ewes and implications for on-farm application

A new mutation in the bone morphogenetic protein 15 (BMP15) gene (FecX R allele) causing increased prolificacy in heterozygous (R+) and sterility in homozygous ewes has been recently described in Rasa Aragonesa, a low-prolificacy Mediterranean breed. The current study determined, first, the effect of this polymorphism on natural and eCG-induced ovulation rate (OR) and the effect of eCG dose on reproductive performance; and second, its effect on prolificacy and its interaction with progestagen + eCG treatment on farms, which have not been reported to date. The FecX R allele increased OR by 0.44 and 0.63 ovulations in young (n = 91) and adult (n = 84) R+ ewes, respectively (both, P < 0.01), increments less than reported in prolific breeds carrying other mutations in BMP15. When the standard dose of eCG used on farms (480 IU) was applied to R+ ewes (n = 36), an extremely high OR (3.95) was recorded, which was accompanied by greater partial failure of multiple ovulations (PFMO). On the contrary, OR using 240 IU in R+ ewes (2.90; n = 35) was similar to 480 IU in wildtype (++) ewes (2.82; n = 48; both P < 0.01 when compared with 480 IU in R+ ewes). No differences were found in the birth weight of the offspring between R+ and ++ eCGstimulated ewes within the same litter size. To validate the genealogy identification on farms, PCR genotyping was carried out in 1,667 ewes from 4 elite flocks, resulting in a negligible misclassification of R+ ewes, which demonstrated that identification by genealogy is a reliable tool to identify FecX R ewes within the breeding program. In recorded farms, the natural litter size of ++ ewes (1.34, n = 599,160 lambing records) was increased due to the FecX R allele by 0.35 lambs (P < 0.0001, n = 6,593 lambing records). A similar increase (0.30) was observed when comparing ++ and R+ ewes treated with 480 IU of eCG (P < 0.0001, n = 62,055 and n = 866, respectively). When applying 480 IU of eCG to R+ ewes, the increase in prolificacy was only due to increased percentages of triplets (P < 0.001) and quadruplets (P < 0.0001), but not of twin births. In conclusion, the favorable reproductive performance of R+ ewes, with 0.63 extra ovulations and 0.35 extra lambs per lambing ewe, is responsible for the increased interest in the use of this polymorphism. Nevertheless, care must be taken in the application of eCG to R+ ewes, with the current results showing that the standard dose increases prolificacy by only increasing triple and higher-order births. © 2011 American Society of Animal Science