Wagyu-sired (n = 20) and Angus-sired (n = 19) steers and heifers were used to compare the effects of sire breed on feedlot performance, carcass characteristics and meat tenderness. Calves were weaned at 138 ± 5 days of age and individually fed a finishing diet consisting of 65% whole corn, 20% protein/ vitamin/mineral supplement and 15% corn silage on a DM basis. Heifers and steers were harvested at 1,180 and 1,235 lb, respectively. Carcasses were ribbed between the 12th and 13th ribs (USDA grading system) and the 6th and 7th ribs (Japanese grading system) to measure fat thickness, longissimus muscle area and intramuscular fat. Two steaks were removed from the 12th rib location and aged for 72 h and 14 d to determine Warner-Bratzler shear force and cooking loss.

* Sire breed by gender interactions was not significant.

* Angus-sired calves had greater average daily gain and dry matter intake than Wagyu-sired calves.

* Wagyu-sired calves had improved feed efficiency than Angus-sired calves.

* Sire breed did not affect hot carcass weight, 12th rib fat or USDA yield grade.

* Carcasses of Wagyu-sired calves had greater marbling scores at the 12th rib than those of Angus-sired calves (770.9 vs 597.3, respectively: 500 = low Choice).

* Carcasses of Wagyu-sired calves also had greater 12th rib intramuscular fat and 6th rib intramuscular fat than Angus-sired calves, resulting in a higher proportion of carcasses grading Prime (65.0% vs. 21.1%).

* Carcasses from Wagyu-sired calves tended to have greater longissimus muscle area at 12th rib, while Angus-sired calves’ carcasses had greater longissimus muscle area at 6th rib.

* Steaks from Angus-sired calves and Wagyu-sired calves had similar tenderness at aging times of 72 h and 14 d. Cooking loss was greater for Angus-sired calves’ than Wagyu-sired calves’ steaks at both 72 h and 14 d.

Using Wagyu sires versus Angus sires on British-based commercial cows combined with early-weaning management strategies has the potential to produce product with greater marbling but is unlikely to significantly enhance tenderness.

Source: Radunz et al., The Ohio State University