Carcass characteristics, colour and eating quality of beef from late maturing suckler bulls finished at pasture with or without concentrate supplementation or indoors on a high concentrate ration.

Context: Their growth and feed efficiency advantages make bull beef production systems attractive alternatives for producers of beef from steers. Finishing bulls from pasture is less costly and would allow bull beef to be marketed as 'grass-fed'. However, such carcasses may not meet the minimum fatness classification of 6.0 (on a 15-point scale) required for some beef markets. This is based in part on a perception that meat from bulls with a lower fatness classification per se is inferior in some quality characteristics. Aim: To determine the comparative carcass and beef quality characteristics of grass-fed and concentrate-fed bulls. Methods: Spring-born, late-maturing breed suckler bull weanlings sourced from commercial beef suckler herds were assigned after their first winter to one of four experimental treatments until they were slaughtered 199 days later at an average age of 19.3 months. Treatments were: (1) grazed grass for 98 days (G), then housed and offered concentrates + grass silage ad libitum indoors for 101 days (G-HC), (2) grazed grass supplemented with concentrates (target 500 g/kg total daily dietary dry matter intake) for 199 days (GC-GC), (3) grazed grass for 98 days, then supplemented with concentrates (target 500 g/kg total daily dietary dry matter intake) at pasture for 101 days (G-GC), or (4) grazed grass only for 199 days (G-G). After slaughter, carcasses were weighed and graded for conformation and fatness. After 72 h, longissimus thoracis (LT) colour was measured. After 14 days ageing, LT was assessed for eating quality characteristics. Results: Carcass weight averaged 399, 381, 374 and 361 kg for G-HC, GC-GC, G-GC and G-G bulls, respectively. Corresponding carcass fat scores were 7.5, 5.1, 5.5 and 4.8, only G-HC exceeded the minimum fat score specification. Meat from bulls finished at pasture was less red but the differences were small. After ageing for 14 days at 2°C, there was no difference in tenderness, flavour or acceptability between striploin steaks from any of the treatment groups. Conclusions: Although none of the grazing groups achieved the current market specification for carcass fat score, this was not reflected in inferior eating quality. Implications: Carcass fat score is a poor indicator of the eating quality of grass-fed bull beef. There is therefore an opportunity for suckler bull producers to access the growing market for 'grass-fed' beef. Their growth and feed efficiency advantages make bull beef production systems attractive alternatives for producers of steer beef. Data from the present study indicate that grazing suckler bulls for 199 days before slaughter does not negatively affect the eating quality of beef when compared to beef from bulls finished indoors on concentrates and grass silage despite a lower carcass fatness. There is an opportunity for suckler bull producers to access the growing market for 'grass-fed' beef. [ABSTRACT FROM AUTHOR]