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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #166161
Title: GENETIC BASIS AND RISK FACTORS OF INFECTIOUS AND NONINFECTIOUS DISEASES IN US HOLSTEINS. I. ESTIMATION OF GENETIC PARAMETERS FOR SINGLE DISEASES AND GENERAL HEALTH

Author
item ABDEL-AZIM, GAMAL - IOWA STATE UNIVERSITY
item FREEMAN, ALBERT - IOWA STATE UNIVERSITY
item Kehrli Jr, Marcus
item KLEM, S - UNIVERSITY OF WISCONSIN
item BURTON, J - MICHIGAN STATE UNIVERSITY
item KUCK, A - COOPERATIVE RESOURCES INT
item SCHNELL, S - COOPERATIVE RESOURCES INT

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2004
Publication Date: 3/1/2005
Citation: Abdel-Azim, G.A., Freeman, A.E., Kehrli, Jr., M.E., Klem, S.C., Burton, J.L., Kuck, A.L., Schnell, S. 2005. Genetic basis and risk factors of infectious and noninfectious diseases in US holsteins. I. Estimation of genetic parameters for single diseases and general health. Journal of Dairy Science. 88(3):1199-1207.

Interpretive Summary: Mastitis, metritis and ketosis diseases are infectious and metabolic diseases that affect more than two-thirds of the dairy cows on over 95% of all dairy farms. On average, U.S. dairy farmers will lose more than $200 per cow annually due to these disease occurrences. This is a legitimate concern to consumers because of potential antibiotic residues as a result of treating cows for mastitis or metritis. The main benefit of the work reported here was the development of a genetic analysis method that can be used with tests of a bull's immune system capacity to resist stress. Bulls with immune systems more resistant to stress will likely be genetically superior for producing offspring who are more resistant to diseases such as mastitis, diarrhea and pneumonia. This technique will be especially useful because we only need to evaluate the immune system of a few bulls. A potential benefit of this research would be less use of antibiotics in cows to treat mastitis through selection of genetically superior breeding stock.

Technical Abstract: Health data collected over a period of four years, 1996 to 1999, from 177 herds in Minnesota and Wisconsin were analyzed to establish genetic basis for infectious and noninfectious diseases. Three types of health traits were targeted, first, selected infectious conditions were fit together in a statistical model to identify animals that are superior in their general immunity for infectious diseases. Generalized immunity may be thought of as a combination of immune responses to a variety of immune system challenges. Second, single infectious and noninfectious diseases were analyzed separately. Third, infectious reproductive diseases as one category of related conditions and cystic ovary disease as one category of 3 related noninfectious ovary disorders were studied. Data were analyzed by a threshold model that included herd, year, season of calving, parity, sire, and cow as cross-classified factors. Days at risk and days in milk at the start of the trial were adjusted for by fitting the days as continuous covariates in the model. A heritability value of 0.202 +/- 0.083 was estimated for generalized immunity. Heritability values of 0.141 and 0.161 were estimated for uterine infection and mastitis, respectively. Heritability of single noninfectious disorders ranged from 0.087 to 0.349. The amount of additive genetic variance recovered in the underlying scale of noninfectious disorders tended to 0 when combining together multiple conditions. Therefore, although the study is in favor of combining infectious diseases into categories of interest, we do not recommend the same approach for noninfectious disorders because of the different mechanisms controlling them.