February 2024 NEBRASKA CATTLEMAN 33 Holstein steers. In addition, beef genetics introduced in the beef x dairy mating reduced frame size, resulting in moderate-framed feeder cattle that reach a finish weight earlier than traditional dairy animals. Reducing frame size and increasing feed efficiency achieves a targeted finished weight on fewer days on feed, subsequently reducing the environmental footprint of beef x dairy feeder cattle compared to straightbred dairy. The ratio of muscle to bone is greatly improved with beef x dairy compared to straightbred dairy, with beef x dairy exhibiting a ratio closer to conventional beef. Data from the West Texas A&M University Beef Carcass Research Center suggests that Holstein steers, beef x dairy and conventional beef exhibit a muscle to bone ratio of 3.1:1, 3.9:1 and 4.1:1, respectively. Beef x dairy cattle also exhibit improved carcass characteristics compared to straightbred dairy that are integral for profitability on the rail. These carcass characteristics include improved dressing percent or yield, larger ribeye area, less angularity over the hip and loin and, occasionally, an increase in hot carcass weight (HCW), although HCW outcomes are variable across data sets. Although the beef x dairy cross has improved feedlot performance and carcass traits compared to straightbred dairy, there is one looming challenge that remains: the prevalence of liver abscess. Liver abscesses occur in all types of cattle but pose a major economic challenge for cattle in the feedlot. Liver abscesses are associated with high grain diets rich in readily fermentable carbohydrates with low inclusions of roughage fed for extended days on feed, resulting in increased prevalence of ruminal acidosis and, therefore, increased liver abscess rate. The prevalence and severity of liver abscess can impact live cattle performance in terms of ADG and carcass traits, such as HCW, marbling ability, ribeye area and carcass trim. Carcass trim is much greater for carcasses that exhibit severe liver abscess, including: • livers with multiple abscesses (A+) that can cause the liver to adhere to other organs of the body (A+ Adhesion); • livers with abscesses that have opened and caused carcass contamination (A+ Open); and • a combination of opened and adhered abscesses (A+ Open + Adhered). Historical data from the West Texas A&M University Beef Carcass Research Center reports a HCW loss of 17 pounds for A+ abscessed livers, 31 pounds for A+ Adhered livers, 33 pounds for A+ Open livers and 46 pounds for A+ Open + Adhered livers. According to a review from Texas Tech University, the average liver abscess frequency for conventional beef is 15 to 30 percent, 50 to 80 percent for straightbred dairy cattle, with beef x dairy cattle exhibiting a 40 to 60 percent liver abscess rate. The increased occurrence of liver abscess in beef x dairy cattle poses a major challenge for feedlot profitability and for the packer, making it a high-priority research topic for academic institutions across the United States. There is no doubt that beef x dairy crossbreeding has upgraded beef potential over straightbred dairy, however, conventional beef cattle still exhibit performance benefits over beef x dairy in terms of ADG, HCW, dressing percent and ribeye area. The marbling potential, traceability and ability to qualify for branded beef programs gives beef x dairy an advantage in the cattle feeding game; however, the liver abscess frequency associated with these crosses poses a large challenge that must be better understood and overcome. ~NC~
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