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Alternative somatic cell count traits exploitable in genetic selection for mastitis resistance in Italian Holsteins.
- Source :
-
Journal of dairy science [J Dairy Sci] 2018 Nov; Vol. 101 (11), pp. 10001-10010. Date of Electronic Publication: 2018 Aug 23. - Publication Year :
- 2018
-
Abstract
- The aim of the present study was to characterize alternative somatic cell count (SCC) traits that could be exploited in genetic selection for mastitis resistance. Data were from 66,407 first-parity Holsteins in 404 herds. Novel SCC traits included average somatic cell score (SCS, log-transformation of SCC) in early lactation (SCS&#95;150), standard deviation of SCS of the entire lactation (SCS&#95;SD), the presence of at least one test-day (TD) SCC >400,000 cells/mL in the lactation, and the ratio of number of TD SCC >400,000 cells/mL to total number of TD in the lactation. Novel traits and lactation-mean SCS (SCS&#95;LM) were analyzed using linear mixed or logistic regression models, including month of calving, year of calving, number of TD, and milk yield as fixed effects, and herd and residual as random terms. A multitrait linear animal model was applied to a random subset of 152 herds (n = 22,695 cows) to assess heritability of and genetic correlations between SCC traits. Alternative SCC traits were affected by the environmental factors included in the model; in particular, results suggested a seasonal effect and a tendency toward an improvement of the udder health status in the last years. Association was also found between novel SCC traits and milk production. Alternative SCC traits exhibited coefficients of additive genetic variation that were similar to or larger than that of traditional SCS&#95;LM. Heritability of novel SCC traits was smaller than heritability of SCS&#95;LM (0.126 ± 0.014), ranging from 0.044 ± 0.008 (SCS&#95;SD) to 0.087 ± 0.010 (SCS&#95;150). Genetic correlations between SCC traits ranged from 0.217 ± 0.096 (SCS&#95;150 and SCS&#95;SD) to 0.969 ± 0.010 (SCS&#95;LM and SCS&#95;150). Alternative SCC traits exhibited additive genetic variation that is potentially exploitable in breeding programs of Italian Holstein population to improve resistance to mastitis.<br /> (Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)
- Subjects :
- Animals
Cell Count veterinary
Disease Resistance
Female
Genetic Variation
Italy
Lactation genetics
Linear Models
Logistic Models
Mammary Glands, Animal
Mastitis, Bovine pathology
Phenotype
Pregnancy
Seasons
Selection, Genetic
Breeding methods
Cattle genetics
Mastitis, Bovine genetics
Milk cytology
Subjects
Details
- Language :
- English
- ISSN :
- 1525-3198
- Volume :
- 101
- Issue :
- 11
- Database :
- MEDLINE
- Journal :
- Journal of dairy science
- Publication Type :
- Academic Journal
- Accession number :
- 30146278
- Full Text :
- https://doi.org/10.3168/jds.2018-14827