Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/29/2009
Publication Date: 1/28/2010
Citation: Garcia, M.D., Thallman, R.M., Wheeler, T.L., Shackelford, S.D., Casas, E. 2010. Effect of Bovine Respiratory Disease and Overall Pathogenic Disease Incidence on Carcass Traits. Journal of Animal Science. 88(2):491-496.
Interpretive Summary: It is essential that the relationship between becoming affected with disease during the production process and the subsequent effects on carcass traits in beef cattle be evaluated. The end product of beef production is wholesale and retail cuts of meat. It has been determined that disease, specifically bovine respiratory disease, can affect both the composition and the quality of a beef carcass. The current study evaluated the effects of respiratory disease individually and respiratory disease in combination with other pathogenic diseases (footrot, pinkeye) in two separate crossbred populations. Animals in either population that became affected with respiratory disease or any of the other recorded diseases had lower adjusted fat thickness measurements, and lower yield grades than their counterparts that remained healthy during the production process. Additionally animals in one of the crossbred populations that were affected by any of the recorded diseases had lower fat yields but increased retail product yields and bone yields. This study further strengthens knowledge about the relationship of disease and the subsequent effects on carcass traits in beef cattle. As such, these relationships should receive consideration by future studies aimed toward selection strategies based on specific traits.
Technical Abstract: The objective was to evaluate the effects of incidence of bovine respiratory disease (BRD) and overall incidence of pathogenic diseases (IPD) on carcass traits. Two independent populations were used; the first population comprised crossbred steers (GPE7; n=642) derived from sires of seven Bos taurus breeds: Angus, Charolais, Gelbvieh, Hereford, Limousin, Red Angus, and Simmental. The second population included crossbred steers (GPE8; n=621) derived from tropically adapted Bos taurus breeds and Bos indicus influenced breeds: Beefmaster, Brangus, Bonsmara, and Romosinuano, as well as Hereford and Angus. Treatment records for BRD, infectious keratoconjunctivitis, and infectious pododermatitis were available for these populations. Incidence of BRD was treated as an independent effect and also combined with other diseases. Incidences of the three microbial pathogenic diseases were pooled into a single trait to represent an overall pathogenic disease incidence. Traits evaluated were HCW, KPH, LM area, marbling score, fat thickness, dressing percentage, yield grade, retail, fat, and bone yields, and meat tenderness. Both, BRD and IPD were associated with differences in yield grade in GPE7 and GPE8. Animals treated for BRD had lower yield grades (P=0.003 and P=0.02, in GPE7 and GPE8, respectively) than untreated animals. Animals treated for IPD had lower yield grades (P=0.0006 and P=0.004, in GPE7 and GPE8, respectively) than untreated animals. Incidence of BRD and IPD were associated with a reduction in fat thickness in GPE7 and GPE8. Animals treated for BRD had lower adjusted fat measurements (P=0.0007 and P=0.01, in GPE7 and GPE8) than untreated animals. Animals treated for IPD also had lower adjusted fat measurements (P=0.0003 and P=0.002, in GPE7 and GPE8) than untreated animals. Additional traits were associated with BRD and IPD in each population. Animals treated for BRD or IPD in the GPE7 population also had lower estimated KPH measurements than unaffected animals. Animals affected with BRD in GPE8 had higher shear force measurements than unaffected animals. Animals affected with IPD in GPE8 had higher HCW and fat yield measurements, but lower bone yield and retail product yield measurements than unaffected animals. The relationship between disease and carcass traits should be given consideration by future studies that aim to develop selection strategies based on specific traits.