Evaluation of fixed sources of variation and estimation of genetic parameters for incidence of bovine respiratory disease in preweaned calves and feedlot cattle12

Abstract

The primary objective of this study was to estimate variance components and heritability of bovine respiratory disease (BRD) incidence in beef calves before weaning and during the finishing phase. The second objective was to investigate the impact of BRD incidence and treatment frequency on performance and carcass traits. Bovine respiratory disease is the biggest and most costly health challenge facing the cattle industry. The 2 populations used consisted of 1,519 preweaned calves and 3,277 head of feedlot cattle. The incidence rate of BRD in preweaned calves was 11.39%, and among treated cattle, 82.1% were treated once, 13.9% were treated twice, and 4.0% were treated 3 times or more. The incidence of BRD (P = 0.35) and the number of treatments (P = 0.77) had no significant effect on weaning BW. Heritability estimates of the entire preweaned population for BRD resistance and number of treatments were 0.11 ± 0.06 and 0.08 ± 0.05, respectively. The genetic correlation estimates for BRD incidence with weaning BW and birth BW were low (−0.02 ± 0.32 and 0.07 ± 0.27, respectively). The same estimate for the number of BRD treatments with weaning BW and birth BW was 0.25 ± 0.35 and 0.30 ± 0.27, respectively. The observed BRD incidence rate for feedlot cattle was observed at 9.43%. Incidence of BRD significantly (P < 0.01) decreased overall and acclimation ADG by 0.06 ± 0.01 kg/d and 0.28 ± 0.03 kg/d, respectively. Carcass traits were also significantly (P < 0.05) affected by BRD incidence; untreated cattle had a 9.1 ± 1.7-kg heavier HCW. Results were similar in the analysis of treatment frequency. The heritability estimate of BRD incidence and the number of treatments were 0.07 ± 0.04 and 0.02 ± 0.03, respectively. Estimates of genetic correlations of BRD incidence with production traits were −0.63 ± 0.22 for acclimation ADG, −0.04 ± 0.23 for on-test ADG, −0.31 ± 0.21 for overall ADG, −0.39 ± 0.21 for final BW, −0.22 ± 0.22 for HCW, −0.03 ± 0.22 for LM area, 0.24 ± 0.25 for fat, and −0.43 ± 0.20 for marbling score. Similar results for the number of treatments and production traits were −1.00 ± 0.68 for acclimation ADG, −0.04 ± 0.39 for on-test ADG, −0.47 ± 0.41 for overall ADG, −0.66 ± 0.40 for final BW, −0.58 ± 0.45 for HCW, −0.12 ± 0.38 for LM area, 0.42 ± 0.50 for fat, and −0.32 ± 0.37 for marbling score. Because of the high economic cost associated with BRD incidence, even these modest estimates for heritability of BRD resistance should be considered for incorporation into beef cattle breeding programs. ABSTRACT:The primary objective of this study was to estimate variance components and heritability of bovine respiratory disease (BRD) incidence in beef calves before weaning and during the finishing phase. The second objective was to investigate the impact of BRD incidence and treatment frequency on performance and carcass traits. Bovine respiratory disease is the biggest and most costly health challenge facing the cattle industry. The 2 populations used consisted of 1,519 preweaned calves and 3,277 head of ...

Genetic parameters estimated at receiving for circulating cortisol, immunoglobulin G, interleukin 8, and incidence of bovine respiratory disease in feedlot beef steers1

“…Presented in Table 4 are previously reported heri tability estimates for BRD, cortisol, total IgG, IgG1, and IgG2 for comparison with those reported in this study. Previous heritability estimates for BRD confirm the estimate (h 2 = 0.17 ± 0.08) in the current research (Snowder et al, 2005(Snowder et al, , 2006(Snowder et al, , 2007Schneider et al, 2010). It is possible that heritability estimates reported in this study were inflated due to dominance; however, given the structure of the data and the unknown breed composition of the dam, these effects were unable to be accounted for.…”

Feeding subtherapeutic antimicrobials to low-risk cattle does not confer consistent performance benefits

“…Unlike commercial feedlots, where sorting of cattle by weight to provide uniform lots at slaughter is common, in our study, steers remained in the same pen for the duration of the feeding period. In a survey of 3277 feedlot cattle, incidence of BRD was estimated at 9.43% (Schneider et al 2010), substantially higher than the 0.4 to 3.5% observed in the present study. The incidence of treatment for bloat in the present study (2 to 5%) would likely have been reduced if ionophores had been included in the diet (Galyean and Rivera 2003), but the presence of monensin in diets would have confounded the observed responses to the other subtherapeutic antimicrobials administered.…”

Scientific Opinion on the welfare of cattle kept for beef production and the welfare in intensive calf farming systems

“…It has also been demonstrated that stressed calves, nervous animals and some breeds are more susceptible to BRD (Fell et al, 1999;Snowder et al, 2006;Cusack et al, 2007;Stilwell et al, 2008c;Pereira and Stilwell, 2011). Resistance to BRD also has a genetic component, although heritability seems to be small (Schneider et al, 2010). "Bullers" (hierarchal lower animals that are constantly harassed by pen mates) are 2.5 times more likely to have respiratory disease and 3.2 times more likely to die (Taylor et al, 1999(Taylor et al, , 2010.…”