Comparative effect of feeding Tifton 85 hay and Pornunça hay as roughage on the performance, carcass characteristics, and meat quality of feedlot lambs

Abstract This study aimed to evaluate the effect of replacing Tifton 85 hay (TH) with Pornunça hay (PH) on intake, nutrient digestibility, performance, carcass characteristics, centesimal composition, and physicochemical parameters of the meat of feedlot lambs. We used 36 Santa Inês male lambs, with an age of 4 months and an initial body weight of 18.60 kg ± 3.80 kg, confined for 71 days, with 15 days of adaptation and 56 days of data collection. The animals were distributed in a completely randomized design in four treatments. Dietary treatments consisted of replacing TH with PH at increasing levels (0%, 33%, 67%, and 100%) within the dry matter of the roughage fraction, maintaining a 40:60 roughage-to-concentrate ratio in the total mixed ration. Dry matter (DM), organic matter, and non-fibrous carbohydrates intake increased ( P < 0.01) by replacing TH with PH. However, there were decreases ( P < 0.01) in the crude protein and neutral detergent insoluble fiber digestibility coefficients of the diet with increasing PH levels. The final weight, daily gain, and feed conversion of the lambs were 30.96 kg, 0.26 kg/day, and 4.38 kg/kg, respectively; the increase in PH in the diet did not affect ( P > 0.05) these values. Conversely, hot and cold carcass weights and yields increased ( P < 0.01) with the dietary replacement of TH by PH. In contrast, TH replacement did not affect ( P > 0.05) the regional carcass composition of the lambs. Furthermore, the substitution of TH with PH had no impact ( P > 0.05) on meat color, water-holding capacity, tenderness, or chemical composition (i.e., ash, protein, and fat contents). We recommend completely replacing Tifton 85 hay with Pornunça hay in the diet of feedlot lambs.