Performance, Carcass Traits, and Meat Fatty Acid Profile of Post-Weaning and Finishing Zebu Steers on Tropical Pasture with Three Low-Intake Supplementation Strategies

Simple Summary Protein and energy supplementation increases the performance of pasture-finished cattle. Three low-intake supplementation strategies (restricted, low, and moderate) were tested during the post-weaning and finishing steers on pasture for 310 days. The moderate supplementation strategy (use of 1 g/kg and 2 g/kg of body weight of concentrated supplementation during the rainy and dry seasons, respectively) increased the weight and fat content of the steers' carcass and the intramuscular fat of the beef. However, steers consuming the moderate supplementation strategy produced meat with lower levels of omega-3 fatty acids. We recommend the use of 1 g/kg and 2 g/kg of body weight of concentrated supplementation during the rainy and dry seasons, respectively, in the post-weaning and finishing steers on tropical pastures. Abstract The study aimed to evaluate the effects of three supplementation strategies on intake, apparent digestibility, feeding behavior, performance, carcass traits, proximate composition, and the fatty acid profile of meat from steers on tropical pasture during the post-weaning and finishing stages. The experiment involved 33 1/2 Holstein x 1/2 castrated Zebu steers weighing 335 +/- 42.90 kg, aged 22 +/- 2 m. The animals were managed on Urochloa brizantha cv. Marandu using an intermittent grazing system with continuous stocking and variable stocking rates for 310 days. The supplementation strategies were as follows: MS/US (mineral salt/urea supplementation): mineral salt in the rainy season and mineral salt with urea in the dry season; US/PS1 (urea supplementation/protein supplementation): mineral salt with urea in the rainy season and protein supplement at 1 g/kg body weight (BW) in the dry season; and PS1/PS2 (protein supplementation 1/protein supplementation 2): protein supplement at 1 g/kg BW in the rainy season and 2 g/kg BW in the dry season. The dry matter intake did not differ significantly (p > 0.05) between strategies. However, the post-weaning PS1/PS2 strategy resulted in higher (p < 0.05) crude protein intake. The final body weight did not differ (p > 0.05) between the strategies, but the average daily gain in post-weaning and finishing was higher (p < 0.05) for MS/US (restricted) animals. Carcass weight, subcutaneous fat thickness, and lipid content in meat were significantly higher (p < 0.05) for steers in the PS1/PS2 group. Steers finished on MS/US produced meat with a higher content of polyunsaturated fatty acids and omega-3 fatty acids (p < 0.05). Concentrate supplementation at 1 g/kg BW during the rainy season and 2 g/kg BW during the dry season is recommended for post-weaning and finishing steers on tropical pasture.