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Inbreeding and crossbreeding parameters for production and fertility traits in Holstein, Montbéliarde, and Normande cows

Author:
Dezetter, C., Leclerc, H., Mattalia, S., Barbat, A., Boichard, D., Ducrocq, V.
Source:
Journal of dairy science 2015 v.98 no.7 pp. 4904-4913
ISSN:
0022-0302
Subject:
Holstein, animal models, backcrossing, breed differences, conception rate, crossbreds, dairy cows, herds, heterosis, inbreeding, inbreeding depression, milk, milk production, purebreds, somatic cells
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.
Agid:
5395787