Short communication: Heritability of susceptibility to infection by Mycobacterium avium ssp. paratuberculosis in Holstein cattle

Abstract

Johne's disease in cattle is the result of infection of the small intestine by Mycobacterium avium ssp. paratuberculosis (MAP), leading to an incurable inflammatory bowel disease (Johne's disease or paratuberculosis). The disease is a concern both for its direct cost to dairy producers and for its zoonotic potential. The objective of this study was to estimate the heritability for susceptibility to infection of cattle by MAP using Johne's testing records (ELISA test for presence of antibodies to MAP in milk or blood) from US Holstein cattle from 2009 to 2016. Data sets were edited to include records from herds with 100 or more total records and sires with 50 or more daughters. Data sets were further edited to include (1) only herds with at least 1 positive test, (2) herds with at least 2.5% positive test results, and (3) herds with at least 5% positive test results to examine the effect of data from herds with higher proportions of positive tests, and presumably higher pathogen exposure, on heritability estimates. Two models were used in this study, a linear sire model and a binary threshold-probit sire model. Both were mixed models considering fixed effects of herd and age at test, the latter as a covariate accounting for linear and quadratic effects; random effects included sire and residual. Analyses were conducted using a restricted maximum likelihood method. Heritability estimates (±standard error) from the linear model were 0.041 ± 0.004, 0.050 ± 0.004, and 0.062 ± 0.007 for data from herds with at least 1 positive test, ≥2.5% positive tests, and ≥5% positive tests, respectively. Heritability estimates from the threshold model were 0.157 ± 0.014, 0.174 ± 0.016, and 0.186 ± 0.021 for data from herds with at least 1 positive test, ≥2.5% positive tests, and ≥5% positive tests, respectively. Heritability estimates from the linear model were affected by population incidence for positive tests, in contrast to estimates from the threshold model, likely accounting for the difference in magnitude of heritability estimates between models and suggesting that the threshold model analysis is the better choice. Heritability estimates increased as data were restricted to herds with presumed higher MAP exposure for both linear model and threshold model analyses. These estimates are similar to previous estimates in other dairy cattle populations and suggest the potential for selection to lessen susceptibility to MAP infection.

Candidate genes associated with the heritable humoral response to Mycobacterium avium ssp. paratuberculosis in dairy cows have factors in common with gastrointestinal diseases in humans

“…The heritability estimate for the humoral response to MAP infection using a sire model and the 33,818 cows in herds with at least 5 positive cows and at least 1 of those cows yielding a positive ELISA to MAP in the present study was of a similar magnitude as that reported by Kirkpatrick and Lett (2018). The range reported by Kirkpatrick and Lett (2018) using sire models and dichotomized humoral (or milk) antibody response to MAP was 0.041 (SE = 0.004) to 0.062 (SE = 0.007). The upper and lower limits of this range were based on cohorts of herds with at least 1 positive test (n = 999 sires represented by 222,872 daughter ELISA records) and ≥5% positive tests (n = 475 sires represented by 65,289 daughter ELISA records), respectively.…”

“…The upper and lower limits of this range were based on cohorts of herds with at least 1 positive test (n = 999 sires represented by 222,872 daughter ELISA records) and ≥5% positive tests (n = 475 sires represented by 65,289 daughter ELISA records), respectively. Perhaps, as suggested by Kirkpatrick and Lett (2018), a sire threshold model analysis is a better analysis to conduct to gain an accurate estimate of the true heritability value for antibody responses to MAP infection. This approach may ameliorate the effects of the prevalence of MAP on a per-cohort basis on the estimates of heritability for dichotomized humoral response to MAP Journal of Dairy Science Vol.…”

Genome-wide association analysis for susceptibility to infection by Mycobacterium avium ssp. paratuberculosis in US Holsteins

“…The first consisted of the US commercial dairy cattle population from 2010 to 2016 based on records for MAP infection recorded in databases of farm records maintained by the Dairy Records Management System and AgSource Cooperative. These data consist of milk ELISA test results for US Holstein cows and have been described in more detail previously (Kirkpatrick and Lett, 2018). After eliminating herds with no positive tests, fewer than 100 test records, and sires with fewer than 50 daughters, records remained for 202,367 cows.…”

“…Knowledge concerning genetics of susceptibility to MAP infection can contribute to disease control programs by facilitating genetic selection for a less susceptible population to reduce incidence of infection in the future. The opportunity for genetic improvement in susceptibility to infection is evidenced by estimates of heritability of MAP infection in dairy cattle ranging from 0.03 to 0.28 (Koets et al, 2000;Mortensen et al, 2004;Gonda et al, 2006;Hinger et al, 2008;van Hulzen et al, 2011;Küpper et al, 2012;Zare et al, 2014;Kirkpatrick and Lett, 2018).…”

Dietary carbon loaded with nano-ZnO alters the gut microbiota community to mediate bile acid metabolism and potentiate intestinal immune function in fattening beef cattle

“…Intestinal inflammation damages the intestinal microbiota of cattle, resulting in diarrhea and bloody stool, weight loss, and death in severe cases [ 7 , 8 ]. Previous studies have shown that intestinal inflammation is the result of the interaction of factors such as the environment, genetic susceptibility and intestinal microbiota [ 9 ].…”