Genetic Variation of Mycobacterium avium ssp. paratuberculosis Infection in US Holsteins
| Autor: | Yu-Mei Chang, George E. Shook, Brian W. Kirkpatrick, M. G. Gonda, Michael T. Collins |
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| Rok vydání: | 2006 |
| Předmět: |
Male
Veterinary medicine Cattle Diseases Paratuberculosis Enzyme-Linked Immunosorbent Assay Biology Feces Genetic variation Genetics medicine Animals Genetic Predisposition to Disease Genetic variability Dairy cattle Sire Heritability medicine.disease Antibodies Bacterial Mycobacterium avium subsp. paratuberculosis Immunology Linear Models Herd Cattle Female Animal Science and Zoology Food Science |
| Zdroj: | Journal of Dairy Science. 89:1804-1812 |
| ISSN: | 0022-0302 |
| DOI: | 10.3168/jds.s0022-0302(06)72249-4 |
| Popis: | The objective of this study was to estimate genetic variability of Mycobacterium avium ssp. paratuberculosis infection in US Holsteins. Blood and fecal samples were collected primarily from daughters of 12 bulls in their second or third lactation. Routine disease testing of the sires documented that they were not infected. Herds without a "suspect" or positive ELISA (sample/positive ratio > or = 0.10) or positive fecal culture test were deleted from the data set. The remaining 4,603 cows from 238 herds and 46 sires were used to estimate heritability of M. paratuberculosis infection. Heritability was estimated with 3 Johne's disease diagnostic tests: 1) fecal culture alone, 2) serum antibody ELISA alone, and 3) both tests (combined) with a positive animal defined as all animals with either a positive fecal culture or ELISA test. Four statistical models were used to estimate heritability: 1) linear (ELISA), 2) threshold (fecal culture and combined), 3) ordered threshold (ELISA), and 4) bivariate linear-threshold (ELISA-fecal culture). A sire model and Bayesian approach using Markov chain Monte Carlo methods were used in each case. Heritability of infection based on the fecal culture test was 0.153 [posterior standard deviation (PSD) = 0.115]. Heritability with the ELISA was 0.159 (PSD = 0.090) with a linear model and 0.091 (PSD = 0.053) with an ordered threshold model. Heritability of the combined tests was 0.102 (PSD = 0.066). Heritability estimates of fecal culture and ELISA with the bivariate model varied slightly from estimates obtained with the univariate models (0.125 and 0.183, respectively), with a corresponding increase in precision (PSD = 0.096 and 0.082, respectively). This study demonstrates that exploitable genetic variation exists in dairy cattle for M. paratuberculosis infection susceptibility. |
| Databáze: | OpenAIRE |
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