ABSTRACT - This study was performed to identify the ideal amount of concentrate required for a diet based on cactus cladodes, sugarcane, and urea used to feed heifers. Twenty Girolando heifers (160±8.39 kg) were randomly distributed into four experimental treatments with 0, 0.40, 0.80, or 1.20 kg day−1 of concentrate. The basal diet contained [on dry matter (DM) basis] 38.1% sugarcane, 56.5% cactus cladodes [Opuntia stricta (Haw). Haw.], 0.5% common salt, 1.1% mineral mixture, and 3.8% urea plus ammonium sulfate. The concentrate contained [on DM basis] 87% corn meal and 13% soybean meal. The basal diet and the concentrate were formulated to provide 13% crude protein (CP). The intake of DM (4.34-4.96 kg day−1), organic matter (3.96- 4.98 kg day−1), CP (0.57-0.64 kg day−1), non-fibrous carbohydrates (2.20-2.61 kg day−1), and metabolizable energy (10.3-12.4 Mcal day−1) increased linearly with concentrate amount. Final body weight (196-224 kg), total body weight gain (36.9-61.2 kg), and average daily body weight gain (0.51-0.85 kg day−1) increased linearly with concentrate amount. The nitrogen balance was positive and increased linearly (54.8-62.3 g day−1) with concentrate amount. Based on the data, we recommend supplying six-monthold Girolando heifers (160 kg body weight) 1.20 kg concentrate day−1 added to a diet based on sugarcane and cactus cladodes plus urea for better productive and economic performance. Keywords: cactaceous, energy supplementation, non-protein nitrogen, reproduction

ABSTRACT - This study was performed to identify the ideal amount of concentrate required for a diet based on cactus cladodes, sugarcane, and urea used to feed heifers. Twenty Girolando heifers (160±8.39 kg) were randomly distributed into four experimental treatments with 0, 0.40, 0.80, or 1.20 kg day−1 of concentrate. The basal diet contained [on dry matter (DM) basis] 38.1% sugarcane, 56.5% cactus cladodes [Opuntia stricta (Haw). Haw.], 0.5% common salt, 1.1% mineral mixture, and 3.8% urea plus ammonium sulfate. The concentrate contained [on DM basis] 87% corn meal and 13% soybean meal. The basal diet and the concentrate were formulated to provide 13% crude protein (CP). The intake of DM (4.34-4.96 kg day−1), organic matter (3.96- 4.98 kg day−1), CP (0.57-0.64 kg day−1), non-fibrous carbohydrates (2.20-2.61 kg day−1), and metabolizable energy (10.3-12.4 Mcal day−1) increased linearly with concentrate amount. Final body weight (196-224 kg), total body weight gain (36.9-61.2 kg), and average daily body weight gain (0.51-0.85 kg day−1) increased linearly with concentrate amount. The nitrogen balance was positive and increased linearly (54.8-62.3 g day−1) with concentrate amount. Based on the data, we recommend supplying six-monthold Girolando heifers (160 kg body weight) 1.20 kg concentrate day−1 added to a diet based on sugarcane and cactus cladodes plus urea for better productive and economic performance. Keywords: cactaceous, energy supplementation, non-protein nitrogen, reproduction Cruz, Antonio Ariclezio Carlos creator Véras, Antonia Sherlânea Chaves creator Oliveira, Júlio César Vieira de creator Santos, Djalma Cordeiro dos creator Chagas, Juana Catarina Cariri creator Neves, Maria Luciana Menezes Wanderley creator Monteiro, Carolina Corrêa de Figueiredo creator Ferreira, Marcelo de Andrade creator text periodical abstract or summary bl. continuing eng ABSTRACT - This study was performed to identify the ideal amount of concentrate required for a diet based on cactus cladodes, sugarcane, and urea used to feed heifers. Twenty Girolando heifers (160±8.39 kg) were randomly distributed into four experimental treatments with 0, 0.40, 0.80, or 1.20 kg day−1 of concentrate. The basal diet contained [on dry matter (DM) basis] 38.1% sugarcane, 56.5% cactus cladodes [Opuntia stricta (Haw). Haw.], 0.5% common salt, 1.1% mineral mixture, and 3.8% urea plus ammonium sulfate. The concentrate contained [on DM basis] 87% corn meal and 13% soybean meal. The basal diet and the concentrate were formulated to provide 13% crude protein (CP). The intake of DM (4.34-4.96 kg day−1), organic matter (3.96- 4.98 kg day−1), CP (0.57-0.64 kg day−1), non-fibrous carbohydrates (2.20-2.61 kg day−1), and metabolizable energy (10.3-12.4 Mcal day−1) increased linearly with concentrate amount. Final body weight (196-224 kg), total body weight gain (36.9-61.2 kg), and average daily body weight gain (0.51-0.85 kg day−1) increased linearly with concentrate amount. The nitrogen balance was positive and increased linearly (54.8-62.3 g day−1) with concentrate amount. Based on the data, we recommend supplying six-monthold Girolando heifers (160 kg body weight) 1.20 kg concentrate day−1 added to a diet based on sugarcane and cactus cladodes plus urea for better productive and economic performance. Keywords: cactaceous, energy supplementation, non-protein nitrogen, reproduction, Publicação on-line; 27 ref.; 6 tables; Sumaries (En) NOVILHO LEITEIRO DIETA MATÉRIA SECA SUPLEMENTO ALIMENTAR Revista Brasileira de Zootecnia (Brazil) Viçosa-MG Sociedade Brasileira de Zootecnia 1997 2024-4310 1516-3598 BR2025000633 v. 49 p. 1-8; (2020) https://www.scielo.br/j/rbz/a/3Ry4PZBfXd6fxQTMRdwLqzr/?format=pdf&lang=en https://www.scielo.br/j/rbz/a/3Ry4PZBfXd6fxQTMRdwLqzr/?format=pdf&lang=en BR-BrBNA 250422 20250422224942.0 eng