The eating quality of beef from young dairy bulls derived from two breed types at three ages from two different production systems

Abstract

Expansion of the Irish dairy herd has led to more dairy breed male calves being available for beef production. This study investigated the physico-chemical and sensory characteristics of beef from Holstein-Friesian (HF) and Jersey × HF (JEX) young bulls fed pasture grass only or pasture grass plus 2 kg concentrate during their first grazing season and slaughtered at 15, 19 or 22 mo of age. Longissimus thoracis (LT) muscles were collected from 67 carcasses. Postmortem pH, ultimate pH (pHu), meat colour, chemical composition, collagen content and solubility were evaluated. After ageing for 21 d, Warner-Bratzler shear force and cooking loss were determined, and assessments by a trained sensory panel were conducted. Meat from older animals was darker. The pHu, moisture and ash contents decreased, while residual roast beef flavour length increased with age. However, increasing age to slaughter did not negatively influence tenderness. JEX beef had lower cooking loss, was darker and redder, in addition to having higher sensory scores for initial tenderness and fattiness than HF beef. Warner-Bratzler variables were positively correlated with cooking loss and chewiness and were negatively correlated with intramuscular fat (IMF) content, soluble collagen and initial tenderness. In summary, most young dairy bull beef samples were acceptably tender after 21 d of ageing and half of them had acceptable IMF content. Slaughter age affected beef colour, pHu, chemical composition and flavour length. The eating quality of meat from the JEX breed type was considered to be superior to that of the HF breed type. Diet during the first season had no effect on meat quality traits.