ABSTRACT The aim of this study was to evaluate intake, digestibility and performance in dairy heifers fed diets containing increasing levels of babassu cake (0, 100, 200 and 300 g kg-1 dry matter - DM) as a substitute for sugarcane treated with calcium oxide. Twenty-four heifers with an initial mean weight of 190.8 + 40.8 kg were used, distributed in a completely randomised design. The dry matter intake (DMI), neutral detergent fibre intake (NDFI) and acid detergent fibre intake (ADFI), as %BW and g BW-0.75 , showed an increasing linear response. The organic matter intake (OMI) showed a linear increase of 40 g day-1, 0.017%BW and 0.66 g BW-0.75 for each 10 g kg-1 increase in babassu cake in the diet. The apparent digestibility of the dry matter (ADDM) and organic matter (ADOM) showed a quadratic response (P < 0.05), with a minimum of 493 g kg-1 DM for 150 g kg-1 DM and 526.5 g kg-1 DM for 320 g kg-1 DM as a substitute for the sugarcane, respectively. The final mean weight was not altered, presenting a value of 299.7 + 45.5 kg. Daily weight gain (DWG) showed a quadratic response, with the highest value at a substitution level of 190 g kg-1 DM. The feed conversion rate of the DM was not affected by the addition of babassu cake, with an average of 4.6 + 0.74 kg DM kg-1 in weight gain. Babassu cake can substitute hydrolysed sugarcane in heifer diets up to 300 g kg-1 DM, with the greatest weight gain seen at a substitution level of 190 g kg-1 DM.

RESUMO A ausência de drenagem associada a elevada evapotranspiração e precipitações irregulares contribuem para o acúmulo de sais no solo reduzindo a absorção de nutrientes e a produtividade. O manejo nutricional é importante para que a cultura expresse seu máximo potencial produtivo, sendo o nitrogênio o macronutriente mais requerido pela cultura do milho. Objetivou-se avaliar a produtividade e os teores foliares na cultura do milho sob diferentes recomendações de adubação nitrogenada e estresse salino. O experimento foi conduzido no período de junho a setembro de 2019, na Universidade da Integração Internacional da Lusofonia Afro-Brasileira em Redenção-CE. O delineamento experimental utilizado foi inteiramente casualizado, em arranjo fatorial 2 x 3, com 6 repetições, sendo dois níveis de condutividade elétrica (0,3 dS m-1 e 3,0 dS m-1), com três recomendações de adubação nitrogenada (0, 50 e 100% da recomendação). As variáveis analisadas foram massa da espiga com e sem palha, produtividade e os teores foliares de N, P, K, Ca, Mg e Na. A irrigação com água salina, diminui a massa da espiga com e sem palha e a produtividade. As recomendações 50% e 100% de adubação nitrogenada proporcionaram maiores valores de massa da espiga com e sem palha e os teores foliares de N, porém diminuíram os de P. As recomendações de 50% e 100% proporcionam maiores valores de produtividade nas duas águas estudadas (0,3 e 3,0 dS m-1). As recomendações 50% e 100% associadas a irrigação com água salina aumentaram os teores foliares de K, Na, Mg e Ca.

ABSTRACT Absence of drainage associated with high evapotranspiration and irregular precipitations contributes to the accumulation of salts in the soil, reducing nutrient absorption and yield. Nutritional management is important for the crop to express its maximum production potential, and nitrogen is the macronutrient most required by the corn crop. The objective of this study was to evaluate yield and leaf contents in corn under different nitrogen fertilization recommendations and salt stress. The experiment was conducted from June to September 2019, at the University of International Integration of Afro-Brazilian Lusophony in Redenção-CE, Brazil. The experimental design used was completely randomized, in a 2 x 3 factorial arrangement, with 6 replicates, with two levels of electrical conductivity (0.3 dS m-1 and 3.0 dS m-1) and three nitrogen fertilization recommendations (0, 50 and 100% of the recommendation). The variables analyzed were unhusked ear weight, husked ear weight, yield and leaf contents of N, P, K, Ca, Mg and Na. Irrigation with saline water (3.0 dS m-1) reduces the unhusked ear weight, husked ear weight and yield. Nitrogen fertilization recommendations of 50% and 100% promoted higher values of unhusked ear weight, husked ear weight and leaf N contents, but reduced leaf P contents. The 50% and 100% recommendations promote higher yield values for the two levels of electrical conductivity studied (0.3 and 3.0 dS m-1). The 50% and 100% recommendations associated with saline water irrigation increased the leaf contents of K, Na, Mg and Ca.

RESUMO A utilização de subprodutos agroindustriais na alimentação de ruminantes apresenta vantagens nutricionais, ambientais e econômicas, contribuindo para a sustentabilidade do sistema de produção. Assim, objetivou-se avaliar o valor nutritivo de dietas contendo torta de babaçu em substituição ao feno de Tifton-85 (70; 140; 210; 280 e 350 g kg-1 de matéria seca; MS). Foram utilizados 25 ovinos machos castrados, com peso corporal médio de 49,6 ± 9,4 kg, alocados em gaiolas metabólicas em delineamento inteiramente casualizado. O consumo voluntário foi obtido pela subtração da quantidade de alimento fornecido pela sobra pesada na manhã seguinte. Para avaliação da digestibilidade dos nutrientes e balanço de nitrogênio (N), amostras de urina e fezes foram coletadas separadamente. O consumo de MS não foi influenciado, contudo o consumo de proteína bruta (PB) e extrato etéreo aumentaram linearmente. A inclusão da torta de babaçu não afetou a digestibilidade da MS (média de 604,6 ± 272,8 g kg-1). A digestibilidade aparente da PB e os teores de nutrientes digestíveis totais apresentaram comportamento linear crescente, enquanto a digestibilidade da fibra em detergente ácido decresceu linearmente. O teor de N retido variou de 9,72 ± 1,12 a 15,51 ± 1,84 g dia-1 e sua relação com o N ingerido variou entre 521,0 ± 26,7 e 578,4 ± 31,8 g kg-1 de N. A inclusão da torta de babaçu, em substituição ao volumoso, incrementou o valor nutritivo da dieta, podendo ser incluída em até 350 g kg-1 da MS na dieta, em substituição ao feno de Tifton-85.

ABSTRACT The use of agro-industrial by-products in feeding ruminants has nutritional, environmental and economic advantages, and helps to sustain the production system. The aim of this study was to evaluate the nutritional value of diets containing babassu cake as a substitute for Tifton-85 hay (70, 140, 210, 280 and 350 g kg-1 dry matter: DM). Twenty-five castrated male sheep with a mean body weight of 49.6 ± 9.4 kg were used, distributed in metabolic cages in a completely randomised design. Voluntary intake was obtained from the difference between the amount of feed provided and the leftovers the following morning. To evaluate nutrient digestibility and nitrogen (N) balance, samples of urine and faeces were collected separately. There was no effect on DM intake; however, crude protein (CP) and ether extract intake increased linearly increased linearly. The addition of babassu cake had no effect on DM digestibility (mean value of 604.6 ± 272.8 g kg-1). Apparent CP digestibility and total digestible nutrient content showed increasing linear behaviour, while the digestibility of acid detergent fibre decreased linearly. The level of retained N varied from 9.72 ± 1.12 to 15.51 ± 1.84 g day-1 with the ratio to ingested N ranging from 521.0 ± 26.7 to 578.4 ± 31.8 g kg-1 N. The addition of babassu cake to replace the roughage, increased the nutritional value of the diet. Babassu cake can be included up to a total of 350 g kg-1 DM in the diet as a substitute for Tifton-85 hay.

ABSTRACT This study was conducted to evaluate the intake, apparent digestibility (AD), and degradability in situ of elephant grass (Pennisetum purpureum Schum) silages containing 0, 35.0, 70.0, 105.0, and 140.0 g kg-1 by-product from dried cashew apple (DCBP) (as fed basis). A completely randomized design with four replicates was adopted. For the study of degradability in situ, one adult male cattle was used in a completely randomized design with split plots. Intake and AD of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, and cellulose were evaluated, and the digestible energy (DE) and nitrogen balance (NB) of the silages were determined. The degradability in situ of DM, CP, and NDF was also determined. Addition of DCBP provided an increase in the intakes of DM, CP, NDF, and ADF. No effects of the levels of addition of DCBP were observed on the coefficients of AD of the silages. Regarding NB, positive values were only detected in the treatment with 105.0 g kg-1 DCBP. In the analysis of the degradability in situ, the incubation periods increased the rates of disappearance of DM, CP, and NDF. However, no effect of the levels of DCBP were observed on the effective degradability of DM. The by-product from dried cashew apple can be included at up to 140.0 g kg-1 in silages of elephant grass, but the high contents of acid detergent insoluble nitrogen may compromise the use and availability of nitrogen to the animals.