Assessing outcomes of genetic selection panels to predict marbling in crossbred beef cattle.

Tanya M Weber,James A Nasados,Brianna J Buseman,Phillip D Bass,Michael J Colle,Kizkitza Insausti,Jessica M Lancaster,Jessie B Van Buren,Jaxon H Smart,Gordon K Murdoch

doi:10.1093/tas/txaa077

Tanya M Weber, James A Nasados + Show 8 more

Open Access

https://doi.org/10.1093/tas/txaa077

Copy DOI

Abstract

The objective of this study was to evaluate the effectiveness of genetic panel marbling indexes [Igenity (IT) and PredicGEN (PG)] to predict marbling and tenderness of crossbred cattle. Steers (n = 23) were harvested at the University of Idaho Meat Science Laboratory, and blood samples were submitted to Neogen and Zoetis for genetic panel analysis. Forty-eight hours postharvest, one boneless strip loin was collected from each carcass, and six 2.54-cm thick steaks were cut from each strip loin. Steaks were aged for 14 and 21 d and assigned to consumer sensory evaluation or Warner–Bratzler Shear Force (WBSF) analysis. Results were analyzed using the Mixed Model procedure of the Statistical Analysis System (SAS Institute, Inc., Cary, NC). Carcasses were grouped by marbling index score into Low IT (IT indexes 3–6; n = 16; marbling score (MS) = 410), High IT (IT indexes 7–10; n = 7; MS = 496), Low PG (PG index <50; n = 9; MS = 398), or High PG (PG index ≥50; n = 14; MS = 458). Mean MS was observed to be greater in High IT steaks than Low IT (P < 0.01) and greater in High PG steaks than Low PG (P = 0.01). There was a trend observed in WBSF between IT marbling groups (P = 0.06); however, no difference in WBSF was observed between PG marbling groups (P = 0.83). Consumers did not report differences between IT marbling groups in terms of acceptability (P = 0.99) or tenderness (P = 0.24). Additionally, consumers could not detect differences between PG marbling groups in terms of acceptability (P = 0.75) or tenderness (P = 0.40). Consumers consistently preferred Choice steaks over Select steaks in terms of acceptability (P = 0.02) and tenderness (P = 0.02). In conclusion, though consumers were not able to tell the difference between steaks from each of the genetic panels, using genetic panels to predict marbling, in conjunction with proper nutrition and handling practices, could be a beneficial tool to producers making decisions about retaining ownership at the feedlot.

Highlights

Marbling is defined as intramuscular fat (Ferguson, 2004) and is influenced by nutrition (Pethick et al, 2004), management (Meyer et al, 2005; Park et al, 2018), and genetics (Utreta and Van Vleck, 2004; Albrecht et al, 2011)
Mean marbling score (MS) was greater in the High PG group than in the Low PG group (P = 0.01)
Carcasses that fell into the High IT group had lesser calculated yield grade (YG) than Low IT carcasses (P = 0.047), and carcasses that fell into the High PG group tended to have lesser YG than Low PG carcasses (P = 0.09)

Summary

Introduction

Marbling is defined as intramuscular fat (Ferguson, 2004) and is influenced by nutrition (Pethick et al, 2004), management (Meyer et al, 2005; Park et al, 2018), and genetics (Utreta and Van Vleck, 2004; Albrecht et al, 2011). It has been well documented that improvements in marbling improves tenderness, both objectively (McBee and Wiles, 1967; Luchak et al, 1998) and via consumer perception (Millar, 1994; Li et al, 2006). It is for these reasons that beef packing facilities utilize services of United States Department of Agriculture (USDA) Agriculture Marketing Service (AMS) grading personnel to assign carcasses a USDA quality grade. This allows beef cattle producers to receive a premium, or avoid a discount, for carcasses with high degrees of marbling while allowing packers to apply discounts for carcasses with poor marbling (USDA Livestock, Poultry, and Grain Market News Division, 2020)

Objectives

Results

Discussion

Conclusion