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-month-old 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.

Resumo: O objetivo deste trabalho foi avaliar o valor nutricional da palma orelha-de-elefante-mexicana (OEM) (Opuntia stricta), armazenada por diferentes períodos, e sua aceitabilidade por novilhas Girolando. Foram utilizadas cinco novilhas distribuídas em quadrado latino 5x5. Os tratamentos foram os seguintes: palma OEM, sem armazenamento; OEM armazenada por três períodos pós-colheita - 7, 14 e 21 dias; e palma-miúda (PM) (Nopalea cochenillifera) sem armazenamento, como tratamento controle. As dietas oferecidas aos animais foram compostas de palmas dos diferentes tratamentos, assim como silagem de cana-de-açúcar e farelo de soja, e foram avaliadas quanto à composição químico-bromatológica, consumo e digestibilidade dos nutrientes. O comportamento ingestivo das novilhas foi avaliado. A palma OEM não diferiu da PM quanto à matéria orgânica, proteína bruta, fibra em detergente neutro corrigida quanto às cinzas e proteína, carboidratos não fibrosos, carboidratos totais, extrato etéreo e matéria mineral; no entanto, a palma OEM diferiu da PM quanto à matéria seca e à fibra em detergente neutro indigestível, quando armazenada por diferentes períodos. O peso das novilhas variou em 1,35 kg, com a baixa inclusão de concentrado na dieta. A palma orelha-de-elefante-mexicana mantém constante seu valor nutricional e sua aceitabilidade pelas novilhas Girolando, após armazenamento por diferentes períodos até 21 dias.

Abstract: The objective of this work was to evaluate the nutritional value of erect prickly pear (EPP) (Opuntia stricta), stored for different periods, and its acceptability by Girolando heifers. Five heifers were distributed in a 5x5 Latin square. The treatments were as follows: EPP without storage time; stored EPP for three post-harvest periods - 7, 14, and 21 days; and cochineal nopal cactus (CNC) (Nopalea cochenillifera) without storage time, as a control treatment. The diets offered to the animals were composed of cacti of the different treatments, as well as sugarcane silage and soybean meal, and were evaluated for their chemical composition, intake, and nutrient digestibility. The ingestive behavior of the heifers was evaluated. The cactus EPP did not differ from the CNC for organic matter, crude protein, neutral detergent fiber corrected for ash and protein, nonfibrous carbohydrates, total carbohydrates, ether extract, and mineral matter; however, EPP stored for different periods differed from CNC for dry matter and indigestible neutral detergent fiber. Heifer weights varied 1.35 kg with the low inclusion of concentrate in the diet. The cactus erect prickly pear maintains constant both its nutritional value and its acceptability to Girolando heifers, after storage for different periods up to 21 days.

ABSTRACT The objective of this study was to evaluate the effect of different concentrate levels (40, 50, 60, and 70% on dry matter basis) on intake, digestibility of nutrients, and performance of heifers fed sugarcane bagasse as exclusive roughage. Twenty Girolando heifers, with an average body weight of 198±25.6 kg were assigned to a completely randomized design, established according to body weight. The intake of dry matter (5.12 to 7.73 kg d-1), organic matter (4.72 to 7.32 kg d-1), crude protein (0.71 to 1.05 kg d-1), and digestible organic matter (3.09 to 4.77 kg d-1) linearly increased with the inclusion of concentrate in the diets. The final weight (238 to 299 kg d-1), body weight gain (0.50 to 1.20 kg d-1), and total weight gain (35.2 to 83.6 kg d-1) linearly increased with the concentrate levels. Considering the occurrence of the first calving at 24 months, a 50:50 ratio of sugarcane bagasse to concentrate seems to be the most appropriate for crossbred heifers.

Objetivou-se avaliar a substituição do farelo de soja pelo farelo de algodão em dietas à base de palma forrageira para vacas em lactação. Foram utilizadas cinco vacas da raça Girolando (peso vivo médio de 490 kg e produção média de 11,5 kg de leite/dia), distribuídas em um quadrado latino 5 × 5, composto de cinco animais, cinco níveis de farelo de algodão (0; 25; 50; 75 e 100%) em substituição ao farelo de soja e cinco períodos experimentais, cada um com 15 dias de duração (10 dias para adaptação e 5 dias para coleta de dados e amostras). As dietas experimentais foram constituídas de palma forrageira (53%), silagem de sorgo (32%) e concentrado (15%). A inclusão do farelo de algodão não influenciou o consumo e a digestibilidade dos nutrientes, cujas médias foram de 15,55 kg/dia e 56,05% para matéria seca (MS); 13,84 kg/dia e 59,31% para matéria orgânica (MO); 0,37 kg/dia e 49,40% para extrato etéreo; 5,32 kg/dia e 30,95% para fibra em detergente neutro; 1,79 kg/dia e 48,14% para proteína bruta; 9,94 kg/dia e 54,31% para carboidratos totais; e 4,43 kg/dia e 80,99% para carboidratos não-fibrosos. O consumo de nutrientes digestíveis totais também não foi influenciado (média de 8,30 kg/dia) pela substituição do farelo de soja pelo farelo de algodão. Igualmente, a produção e composição do leite também não foram afetadas e apresentaram médias de 11,56; 11,41, kg leite/dia e 4,45; 12,75; 3,95 e 3,42% para produção de leite, produção de leite corrigida para 4% de gordura, teores de lactose, sólidos totais, gordura e proteína, respectivamente. Recomenda-se a substituição do farelo de soja pelo de algodão para vacas de baixa produção.

The objective of this study was to evaluate the replacement of soybean meal by cottonseed meal in the diet of dairy cows fed diets based on spineless cactus. Five Girolando lactating cows were used, with average live weight of 490 kg and average production of 11.5 kg of milk/day, distributed in a 5 × 5 Latin square design (5 animals, 5 treatments and 5 experimental periods). Each experimental period lasted 15 days, 10 days being for the adaptation of the animals to the diet and 5 days for data collection. The experimental diet consisted of spineless cactus (53%), sorghum silage (32%) and concentrate (15%). The cottonseed meal replaced 0, 25, 50, 75 and 100% of soybean meal in the concentrate. The intake, milk yield and composition were evaluated. The nutrients intake and digestibility were not affected by the treatments, with an average of 15.55 and 56.05; 13.8 and 59.31, 0.37 and 49.40, 5.32 and 30.95, 1.79 and 48.14; 9.94 and 54.31, 4.43 kg/day and 80.99%, for the dry matter, organic matter, ether extract, neutral detergent fiber, crude protein, total carbohydrates and non-fibrous carbohydrates, respectively. The total digestible nutrients were not affected (average of 8.30 kg/day). Similarly, the milk yield and composition, fat corrected milk yield (4%), lactose, total solids, fat and protein were not affected by replacement (11.56, 11.41 kg milk/day and 4.45, 12.75, 3.95 and 3.42%, respectively). Recommended the replacement of soybean meal by cottonseed meal for low production dairy cows.