Nutrient Composition of Autochthonous Beef from Southwest Spain.

The aim of this study was to evaluate the nutritional composition of beef from five autochthonous calving breeds from Southwest Spain (Retinta, Pajuna, Marismeña, Berrenda en Colorado, and Lidia) reared under their traditional production systems. Longissimus dorsi samples were analyzed for pH, fat, moisture, ash protein content, mineral composition, fatty acid profile, and volatile compounds. Carcass weights of calves ranged from 108 to 328 kg according to the Spanish market, with significant breed differences in fat (range 2.98-8.41%), moisture (69.47-72.62%), and protein (20.98-23.82%), but not in ash (1.03-1.17%). Sodium levels were below 120 mg/100 g, allowing all breeds to be classified as low-sodium, while phosphorus values supported a high-phosphorus label. The Pajuna, Berrenda en Colorado, and Lidia breeds showed higher levels of beneficial fatty acids such as EPA, DPA, DHA, and CLA, with n-6/n-3 ratios ≤ 4, while Retinta and Marismeña presented higher ratios (6.09 and 5.23, respectively). The breeds from Southwest Spain stand out for their content in ketone, ester, and aromatic hydrocarbon volatile compounds linked to the intake of grass, forage, and food concentrate. These results highlight the favorable nutrient profiles and distinctive traits of Spanish autochthonous cattle breeds, emphasizing their value in sustainable production and conservation programs.