Prevalence of Right Sided Heart Failure in Angus Influenced and Beef on Dairy Fattening Feedlot Cattle

Abstract Bovine Congestive Heart Failure (BCHF) exists in feedlot cattle at low to moderate elevations, but previous studies focused solely on beef cattle. The economic advantage of breeding beef sires to dairy dams results in an increase in the number of beef on dairy (DXB) crossed cattle in the feedlot system, though not much is known on the comparative prevalence of BCHF in DXB compared with beef cattle breeds. The inclusion of a new breeding program for dairy producers leads to another potential source of variability (i.e., dairy influenced genetics) for heart disease research in the feedlot sector. Heart failure in the feedlot is typically known as Feedlot Heart Disease (FHD) and has been reported to result in unfavorable carcass and growth performance damaging quality and efficiency throughout the lifetime of cattle. The unknown prevalence of heart failure in DXB cattle may be a problem for producers since little is known about which breeds are at greater risk. The severity of FHD for both beef and DXB cattle was determined by individually grading hearts at harvest using a 1 to 5 grading system corresponding to the stage of heart remodeling with a score of 1 (normal heart) and greater scores indicating increased remodeling. The objective of this study was to examine the prevalence of heart remodeling in both an Angus influenced group of beef cattle and a sample of DXB cattle. Heart scores were collected on an Angus influenced group raised in the panhandle of Texas (1,103m) and totaled 1,634 animals (Grade 1: 347; Grade 2: 848; Grade 3: 371; Grade 4: 68; Grade 5: 0). Heart scores were collected on a DXB group raised in western Kansas (846 m) and totaled 2,328 animals (Grade 1: 913; Grade 2: 1,162; Grade 3: 225; Grade 4: 27; Grade 5: 1). Proportions of moderate to severe heart remodeling were 0.27 and 0.11 for Angus influenced and DXB, respectively. In conclusion, preliminary research on heart remodeling in both samples indicates a greater proportion of cattle experiencing heart remodeling in beef breeds versus the DXB cattle, although further investigation is needed to make conclusions about the consistency of heart remodeling and breed effects.