title: Monitoring changes in the demographic and genealogical structure of the main Spanish local beef breeds.
abstract: Demographic and pedigree analyses describe the structure and dynamics of livestock populations. We studied information recorded in the herdbooks of Asturiana de los Valles (AV; N = 458,806), Avileña-Negra Ibérica (ANI; N = 204,623), Bruna dels Pirineus (BP; N = 62,138), Morucha (Mo; N = 65,350), Pirenaica (Pi; N = 217,428), Retinta (Re; N = 135,300), and Rubia Gallega (RG; N = 235,511) beef breeds from their creation until 2009. All breeds have increased in the number of registered cows in recent years. In all breeds, herds do not behave as isolated entities and a high rate of exchange of breeding males between herds exists. A percentage of herds (12-52%) make some type of selection and sell bulls to other herds. There were large differences in average number of progeny per bull, ranging from 15.6 (AV) to 373.7 animals (RG, with a high incidence of AI). Generation interval estimates ranged from 4.7 (AV) to 7.6 (RG) yr in the sire pathway and from 5.95 (AV) to 7.8 (Mo) yr in the dam pathway. Density of pedigrees varied among breeds, with Pi, ANI, and Re having the more dense pedigrees, with average completeness indexes of more than 96% in the first generation and 80% when 6 generations were considered. A general increase in average inbreeding was observed in all breeds in the years analyzed. For animals born in 2009, average inbreeding coefficients ranged from 0.6 (BP) to 7.2% (Re) when all animals were considered and from 3.6 (Pi) to 17.6% (BP) when only inbred animals were considered. Due to the lack of completeness of pedigrees in most populations, inbreeding coefficients may be considered as a lower bound of the true parameters. The proportion of inbred animals tended to increase in the periods analyzed in all breeds. Differences between inbreeding and coancestry rates (except in RG) suggest the presence of population structure. Effective population size (Ne) based on the inbreeding rate estimated by regression ranged from 43 to 378 for Re and BP, whereas Ne estimates based on coancestry were greater, with a range of 100 for RG to 9,985 for BP. These facts suggest that an adequate mating policy can help to monitor inbreeding so as not to lose genetic variability. Effective number of ancestors in 2009 for 6 of the breeds ranged from 42 (RG) to 220 (AV), with BP having much a greater value, and was lower than was the effective number of founders in all breeds, suggesting the existence of bottlenecks.
authors.affiliation: Grup de Recerca en Remugants, Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193-Bellaterra, Barcelona, Spain.
authors.forename: J J
authors.initials: JJ
authors.lastname: Cañas-Álvarez
authors.affiliation: Departamento de Anatomia, Embriologia y Genética, Universidad de Zaragoza, 50013-Zaragoza, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Gónzalez-Rodríguez
authors.affiliation: Departamento de Mejora Genética Animal, INIA, 28040-Madrid, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Martín-Collado
authors.affiliation: Departamento de Producción Animal, Universidad de Córdoba, 14071-Córdoba, Spain MERAGEM, Universidad de Córdoba, 14071-Córdoba, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Avilés
authors.affiliation: Departamento de Anatomia, Embriologia y Genética, Universidad de Zaragoza, 50013-Zaragoza, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Altarriba
authors.affiliation: Departamento de Ciencias Agroforestales, Universidad de Valladolid, 34004-Palencia, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Baro
authors.affiliation: Departamento de Producción Animal, Universidad de León, 24071-León, Spain.
authors.forename: L F
authors.initials: LF
authors.lastname: De la Fuente
authors.affiliation: Departamento de Mejora Genética Animal, INIA, 28040-Madrid, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Díaz
authors.affiliation: MERAGEM, Universidad de Córdoba, 14071-Córdoba, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Molina
authors.affiliation: Departamento de Anatomia, Embriologia y Genética, Universidad de Zaragoza, 50013-Zaragoza, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Varona
authors.affiliation: Grup de Recerca en Remugants, Departament de Ciència Animal i dels Aliments, Universitat Autònoma de Barcelona, 08193-Bellaterra, Barcelona, Spain jesus.piedrafita@uab.es.
authors.forename: J
authors.initials: J
authors.lastname: Piedrafita
mesh_terms: D000818:Animals; D001947:Breeding / Q000379:methods / Q000706:statistics & numerical data*; D002417:Cattle / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D007178:Inbreeding; D008297:Male; D010375:Pedigree; D011156:Population Density; D013030:Spain
keywords: beef cattle; inbreeding; local breeds; pedigree