ABSTRACT. The objective was to evaluate the partial substitution of sugarcane treated with urea by elephant grass in the feeding of crossbred cows in lactation. Eight crossbred cows (Holstein x Gyr) were used, with 474 kg of body weight (standard deviation = 46.15 kg) and 8.15 kg of milk per day. The animals were housed in individual stalls, distributed in two 4 x 4 Latin squares, and the treatments were: sugar cane; sugar cane corrected with 0.5% of urea and ammonium sulfate (9:1); 75% of sugar cane + 25% of elephant grass and 50% of sugarcane + 50% of elephant grass, based on natural matter. In addition to the treatments, it was provided water and mineral salt ad libitum and 3 kg of concentrate supplement (24% crude protein), based on corn meal and soybean meal, supplied in two portions during the morning and afternoon milking. There was a treatment effect on the intake and digestibility of dry matter and nutrients, except for non-fibrous carbohydrate intake, and there was no effect on milk production and composition. It can be concluded that the substitution of sugarcane by elephantgrass (25 and 50%) increases the intake and decreases the digestibility of DM and OM, without affecting milk production, when the cows are supplemented with 3 kg of concentrate, containing 24% of protein per day.

Objetivou-se avaliar o valor nutritivo de silagens de diferentes cultivares de sorgo. Foram utilizados cinco ovinos machos, castrados, sem padrão racial definido, com peso corporal médio de 26 kg. Os animais foram distribuídos em delineamento experimental quadrado latino (5 x 5), e alojados em gaiolas para estudo de metabolismo, equipadas com coletores de fezes e urina. Os tratamentos consistiram de silagem de cinco cultivares de sorgo: IPA 1011, IPA 2564 (graníferos), IPA 2502 (duplo propósito), IPA SF-25 e IPA 467 (forrageiros). O teor de proteína das silagens foi corrigido para 12% com a adição da mistura ureia-sulfato de amônio (9:1). As cultivares 1011, 2564 e 2502 proporcionaram maiores consumos de matéria seca, carboidratos totais, nutrientes digestíveis totais e menores teores de fibra em detergente neutro. As cultivares 1011 e 2564 proporcionaram maiores coeficientes de digestibilidade aparente da matéria seca e orgânica, e juntamente com o 467 e o SF-25, os maiores coeficientes de digestibilidade aparente da proteína bruta. As cultivares 1011 e 2564 proporcionaram maiores teores de nutrientes digestíveis totais. Todos as cultivares proporcionaram balanço de nitrogênio positivo. Em função dos valores observados para consumo e digestibilidade dos nutrientes, as silagens das cultivares graníferas apresentam maior potencial para a alimentação de ruminantes.

Nutrition values of silages from different sorghum cultivars are evaluated. Five 26-kg castrated crossbred lambs, housed in pens equipped with feces and urine collectors for the study of their metabolism, were employed in a 5 x 5 Latin square experimental design. Treatments consisted of silage from five different sorghum cultivars: IPA 1011 and IPA 2564 (grain sorghum), IPA 2502 (dual purpose sorghum), IPA FS-25 and IPA 467 (forage sorghum). Protein level was corrected to 12% by adding a mixture of urea: ammonium sulfate (9:1). Treatments IPA 1011, IPA 2564 and IPA 2502 provided high intake of dry matter, total carbohydrate and total digestible nutrients, and low intake of neutral detergent fiber. Cultivars IPA 1011 and IPA 2564 provided high apparent crude protein digestibility coefficient, whereas cultivars IPA 1011 and IPA 2564 had high total digestible nutrient levels. All cultivars provided positive nitrogen. Owing to nutrient intake and digestibility values, grain sorghum silages evidenced high potential in ruminant nutrition.

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.