Abstract: To investigate the effects of different slaughter ages on the meat quality, intramuscular fat content and muscular long-chain fatty acid content of the Longissimus dorsi (LD) muscle of Xianan cattle (Bos taurus), newborn, 12-month-old and 24-month-old Xianan cattle (three bulls of each age with similar body mass) were slaughtered to measure meat quality indexes of Longissimus dorsi including pH, cooking loss, drip loss and shear force. Oil red O stained sections were prepared and examined. Triglyceride (TG) levels and intramuscular fat content were detected, and the composition of medium-chain and long-chain fatty acids in the muscle was analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that the pH of the LD of 12-month-old cattle was significantly higher than that of newborn cattle (P < 0.05), and the cooking loss of the LD of newborn cattle was significantly higher than that of 24-month-old cattle (P < 0.05). The linoleic acid content in the LD of 24-month-old cattle was significantly higher than that in newborn and 12-month-old cattle (P < 0.01). The arachidonic acid content in the LD of cattle aged 12 and 12 months was significantly higher than that in newborn cattle (P < 0.05). The total polyunsaturated fatty acid (PUFA) content in the LD of 24-month-old cattle was higher than that in newborn and 12-month-old cattle. In this study, there were no significant differences in the drip loss and shear force of the LD among cattle of different ages. In terms of intramuscular fat content and long-chain fatty acid composition, it is suggested that the meat of 24-month-old cattle is more in line with human health standards.

Key words: slaughter age; Xianan cattle; meat quality; intramuscular fat; long-chain fatty acids