title: Inbreeding and crossbreeding parameters for production and fertility traits in Holstein, Montbéliarde, and Normande cows.
abstract: Breed differences and nonadditive genetic effects for milk production traits, somatic cell score (SCS), conception rate (CR), and days to first service (DFS) were estimated for Holstein × Montbéliarde and Holstein × Normande crossbreds, using an animal model adapted from the French genetic evaluation and extended to across-breed analysis. Inbreeding and breed differences were estimated from all purebred recorded cows. Only records from 1,137 herds with Holstein × Montbéliarde crossbred cows and from 1,033 herds with Holstein × Normande crossbred cows were used to estimate crossbreeding parameters. In these herds, crossbred cows represented about 13% of the total number of recorded animals compared with <1% when all herds were considered. Compared with the Montbéliarde and Normande breeds, the Holstein breed was genetically superior for production [+951kg and +2,444kg for 305-d mature-equivalent (305ME) milk, +40kg and +102kg for 305ME fat, +17kg and +54kg for 305ME protein, respectively] and inferior for fertility traits (-12 and -9% for CR, respectively). Inbreeding depression caused loss of yield for production traits (from -32 to -41kg of 305ME milk, -1.4 to -1.7kg of 305ME fat, and -1.1 to -1.3kg of 305ME protein per inbreeding percentage), a small increase in SCS (+0.001 to 0.006) and DFS (+0.12d), and a decrease in CR (-0.27 to -0.44%). Favorable heterosis effects were found for all traits (+494 to 524kg of 305ME milk, +21 to 22kg of 305ME fat, +15 to 16kg of 305ME protein, -0.05 to -0.04 SCS, +2 to 3% for CR, and -3 to 6d of DFS), to such a point that F1 crossbreds could compete with Holstein cows for milk production while having a better fertility. However, recombination losses suggested that some F1 heterosis was lost for backcross cows.
authors.affiliation: PASS'SAS, 4 rue des Epicéas, 25640 Roulans, France; L'Université Nantes Angers Le Mans (LUMAN), Oniris, UMR Biology, Epidemiology and Risk Analysis (BioEpAR), La Chantrerie, 44307 Nantes, France; Département de Productions Animales, Unité de Recherche Systèmes d'Élevage, École Supérieure d'Agriculture d'Angers ESA(2), 49007 Angers, France. Electronic address: c.dezetter@groupe-esa.com.
authors.forename: C
authors.initials: C
authors.lastname: Dezetter
authors.affiliation: Institut de l'Elevage, 149 rue de Bercy, 75595 Paris, France.
authors.forename: H
authors.initials: H
authors.lastname: Leclerc
authors.affiliation: Institut de l'Elevage, 149 rue de Bercy, 75595 Paris, France.
authors.forename: S
authors.initials: S
authors.lastname: Mattalia
authors.affiliation: Institut National de la Recherche Agronomique (INRA), UMR1313 Génétique Animale et Biologie Intégrative (GABI), 78352 Jouy-en-Josas, France.
authors.forename: A
authors.initials: A
authors.lastname: Barbat
authors.affiliation: Institut National de la Recherche Agronomique (INRA), UMR1313 Génétique Animale et Biologie Intégrative (GABI), 78352 Jouy-en-Josas, France.
authors.forename: D
authors.initials: D
authors.lastname: Boichard
authors.affiliation: Institut National de la Recherche Agronomique (INRA), UMR1313 Génétique Animale et Biologie Intégrative (GABI), 78352 Jouy-en-Josas, France.
authors.forename: V
authors.initials: V
authors.lastname: Ducrocq
mesh_terms: D000818:Animals; D002417:Cattle / Q000235:genetics / Q000502:physiology*; D005260:Female; D005298:Fertility; D005602:France; D006823:Hybrid Vigor; D006824:Hybridization, Genetic; D007178:Inbreeding; D007774:Lactation; D008892:Milk / Q000737:chemistry* / Q000378:metabolism*; D011995:Recombination, Genetic
keywords: dairy crossbreeding; functional trait; nonadditive effect; production trait