Beef cattle

Heritability of bovine respiratory disease in weaned beef calves

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Abstract

Bovine respiratory disease complex (BRD) is one of the most common and economically important diseases in the beef industry, particularly in feedlot production. Post-weaning BRD costs the U.S. feedlot industry as much as $1 billion annually in production losses due to mortality, treatment costs, additional labor, and decreased performance and carcass quality. While good management practices are effective at reducing the impacts of BRD, there is potential for genetic improvement in calf health. The objective of this study was to compare heritability estimates between linear and binomial models for BRD incidence. Post-weaning health records were obtained on purebred and crossbred beef calves born from 2016 to 2024 from a seedstock operation in southwest Iowa. Relationships were built using a pedigree consisting of 14,613 individuals. Initial data processing was performed using R software version 4.4.1. After cleaning, 5,676 bulls, steers, and heifers were available for analysis. Breeds represented in the dataset were Angus, Simmental, South Devon, Angus x Simmental, Angus x South Devon, and Angus x Simmental x South Devon. Disease incidence was a binary trait defined as never receiving treatment (0) or receiving at least one treatment for BRD (1). Most calves remained healthy during the post-weaning period and were never treated (n = 4,030). Genetic analysis was performed using ASReml version 4.2 software package. Animal was included as a random effect and fixed effects included in the models were breed, date of birth, and contemporary group. Contemporary group consisted of birth year and weaning pen. The heritability of BRD incidence was evaluated using two univariate models. The first model analyzed BRD as a linear model and resulted with a heritability estimate of 0.049 ± 0.020. Given the binary nature of BRD incidence, the data would be better represented by a probit model. An estimated heritability using a probit model was 0.074 ± 0.026. Heritability was slightly higher when estimated with the probit model, reflecting its use of the underlying liability scale and variance structure appropriate for the binary response. As expected, estimated breeding values from the probit model had greater variability than the linear model. These results indicate that selection for improved calf health is plausible. However, further research is warranted to evaluate different trait definitions that may provide greater opportunities for use in breeding programs, such as disease severity.

Keywords: 2026

How to Cite:

Tarochione, A., Havens, R. & Culbertson, M., (2026) “Heritability of bovine respiratory disease in weaned beef calves”, World Congress on Genetics Applied to Livestock Production Digital Archive 2026(1): 2287149. doi: https://doi.org/10.31274/wcgalp.24223

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