Genetic Basis and Risk Factors for Infectious and Noninfectious Diseases in US Holsteins. I. Estimation of Genetic Parameters for Single Diseases and General Health

Abstract

Health data collected from 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, available infectious conditions were used to identify animals that are superior in their general immunity (including innate 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 using a threshold model that included herd, calving year, season of calving, and parity as cross-classified fixed factors; and sire and cow within sires as random effects. Days at risk and days in milk at the beginning of a record were included 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 zero when combining multiple conditions. The study supports combining infectious diseases into categories of interest but we do not recommend the same approach for noninfectious disorders.

Genetic parameters for producer-recorded health data in Canadian Holstein cattle

“…Therefore, the incidence in the first week of lactation is very low; it increases sharply after 70 DIM, a time when producers realise that the animal did not cycle again since calving. Although not confirmed in our results, COD is one of the diseases showing the largest positive effect of DAR on a risk of disease (Abdel-Azim et al, 2005). There is a higher risk of COD in a longer lactation, but this estimate may be biased by the fact that collecting COD data is rarely done at the beginning of lactation.…”

“…If animals were grouped according to health status (Table 3), there would be a difference in the average of DAR between sick and healthy animals of 5.4 days for LDA (42.4 days v. 47.8 days). Abdel-Azim et al (2005), using the whole length of lactation for all diseases, found a slightly positive value for the regression coefficients on DAR for LDA using a linear model. Similar result was also obtained in this study, when using threshold models.…”

“…The effect of the length of the period at risk has been accounted for in previous analyses of health data (e.g. de Haas et al, 2002;Abdel-Azim et al, 2005).…”

Incidence Rates of Clinical Mastitis among Canadian Holsteins Classified as High, Average, or Low Immune Responders

“…Although an antagonistic relationship exists between these responses (9,10), an optimal balance is required for broad-based disease resistance (11). Adaptive immune response traits are heritable (9), and their inclusion in breeding indices has been suggested to improve inherent disease resistance in dairy cattle (12,13).…”

Antibodies and longevity of dairy cattle : genetic analysis

“…An currently practised approach to breed for improved disease resistance is to select animals with an enhanced specific immune response (Wilkie and Mallard, 1999;Abdel-Azim et al 2005;Mallard et al 2011). In dairy cattle specific cellmediated and antibody mediated immune responses have been used as indicator of immune response Cartwright et al, 2011;Hine et al, 2011;Thompson-Crispi et al 2012).…”