Edad y prolificidad al primer parto de corderas Rasa Aragonesa portadoras o no del alelo FecXR
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Date
2017
Authors
Lahoz Crespo, BelénJiménez Hernando, M.J.
Jurado, J.J.
Calvo Lacosta, Jorge Hugo
Galeote, Ana Isabel
Blasco, María Eugenia
Folch Pera, José
Fantova Puyalto, Enrique
Alabart Alvarez, José Luis
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Abstract
Desde el descubrimiento en 2007 en la raza Rasa Aragonesa del polimorfismo prolífico
Fecx" en el gen BMP15 (Jurado y Calvo, 2007; Martinez-Royo et al., 2008) el número de
animales de este genotipo se ha incrementado de manera continua en las ganaderías.
Actualmente el 58% (164/283) de los rebaños que forman parte del programa de selección
por prolificidad de Unión de Productores de Rasa Aragonesa (UPRA-Grupo Pastores) tienen
hembras portadoras heterocigotas (R+), contabilizándose en total 13.024 hembras de este
genotipo. De estos, el 38% (63/164) tienen más de un 10% de ovejas R+ (Jurado y Jiménez,
2016). Esto se debe a los efectos demostrados de este polimorfismo sobre la prolificidad de
las ovejas heterocigotas y su consecuente impacto positivo en la rentabilidad de las
ganaderfas. Las ovejas heterocigotas presentan cambios importantes a nivel de sus follculos
ováricos. En concreto, se ve afectada su sensibilidad a las gonadotropinas de manera que
son capaces de ovular un mayor número de foliculos con un menor diámetro, y en algunas
razas viene acompañado de alteraciones endocrinas relevantes (Fabre et al., 2006). Estos
cambios podrfan afectar la entrada en pubertad de los animales. El objetivo del presente
trabajo consiste en evaluar la edad al primer parto y la prolificidad de las corderas R+ y ++
en las ganaderlas a lo largo de los últimos 12 años.
Since the discovery in 2007 of !he prolific Fecx" polymorphism in !he Rasa Aragonesa sheep breed, !he number of carrier ewes (R+) in farms has significantly increased. These ewes present changes in their ovarían follicles which could lead to endocrine alterations and might affect !he onset of puberty. The objective of !he present work was to evaluate !he age al first lambing (AFL) and !he prolificacy in farm conditions of R+ ewe lambs over !he las! 12 years. AFL was similar in R+ and non-carrier (++) ewes (601 vs_ 600 days), with similar effects of year and month of birth. As expected, prolificacy was higher in R+ comparad to++ ewe lambs (1.47 vs. 1-19; P<0.0001). Over !he studied period AFL significantly decreased and prolificacy significantly increased among years, which demonstrated !he improvements made by sorne farms which perform Al and work with prolific genotypes_ Prolificacy and AFL were related, so that a delay of 365 days in AFL give rise to an increase of 0.21 lambs/lambing ewe lamb, with no interaction with genotype. lt should be taken into account to reach equilibrium between desired age and prolificacy al first lambing.
Since the discovery in 2007 of !he prolific Fecx" polymorphism in !he Rasa Aragonesa sheep breed, !he number of carrier ewes (R+) in farms has significantly increased. These ewes present changes in their ovarían follicles which could lead to endocrine alterations and might affect !he onset of puberty. The objective of !he present work was to evaluate !he age al first lambing (AFL) and !he prolificacy in farm conditions of R+ ewe lambs over !he las! 12 years. AFL was similar in R+ and non-carrier (++) ewes (601 vs_ 600 days), with similar effects of year and month of birth. As expected, prolificacy was higher in R+ comparad to++ ewe lambs (1.47 vs. 1-19; P<0.0001). Over !he studied period AFL significantly decreased and prolificacy significantly increased among years, which demonstrated !he improvements made by sorne farms which perform Al and work with prolific genotypes_ Prolificacy and AFL were related, so that a delay of 365 days in AFL give rise to an increase of 0.21 lambs/lambing ewe lamb, with no interaction with genotype. lt should be taken into account to reach equilibrium between desired age and prolificacy al first lambing.
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Keywords
Raza Rasa aragonesa
Bibliographic citation
XVII Jornadas sobre Producción Animal: Zaragoza, 30 y 31 de mayo de 2017, p. 365-367
AGROVOC subjects
OvinosReproductividad
Madurez sexual
Other field subjects
Producción y sanidad animalSponsorship
Financiado con fondos FEDER a través de POCTEFA (Proyecto
PIRINNOVI EFA103/15) y CDTI (Proyecto IDl-20160426).