Formas de utilização do milho em suplementos para novilhos na fase de terminação em pastagem no período das águas: desempenho e parâmetros nutricionais Corn, in different forms, in multiple supplements for finishing crossbred steers on pasture during rainy season: performance and nutrition parameters

Avaliou-se a influência da forma de utilização do milho em suplementos no desempenho de novilhos na fase de terminação, durante o período das águas, em pastagem de capim-braquiária. Utilizaram-se 16 bovinos mestiços com peso inicial de 384 kg e 18 meses de idade, distribuídos em delineamento inteiramente casualizado, com quatro tratamentos mistura mineral (MM) (controle); milho triturado (MT); milho desintegrado com sabugo (MDS); e milho desintegrado com palha e sabugo (MDPS) - e quatro repetições. Os animais foram mantidos em pastagem de 6 ha de Brachiaria decumbens Stapf, dividida em quatro piquetes de 1,5 ha, com disponibilidade de matéria seca total (MST) de 4,77 t/ha e MSpd (matéria seca potencialmente digestível) de 3,14 t/ha. Para avaliação dos parâmetros nutricionais, utilizaram-se quatro animais mestiços fistulados no esôfago, no rúmen e no abomaso, com peso médio inicial de 390 kg, distribuídos em quadrado latino 4 &#215; 4, composto de quatro tratamentos e quatro períodos experimentais. Os animais do grupo controle receberam mistura mineral diariamente (60 g/dia), enquanto os demais receberam os suplementos (1,0 kg/dia). Os suplementos múltiplos não influenciaram o desempenho dos animais, mas as concentrações séricas de uréia foram maiores nos animais sob suplementação. O consumo de PB, assim como a digestibilidade total de PB, aumentou com o uso dos suplementos múltiplos. Os animais do grupo controle (mistura mineral) apresentaram maior consumo de matéria seca e matéria orgânica de pasto. O uso de suplemento múltiplo (1 kg/dia) no período das águas promoveu aumento numérico de até 165 g/animal em relação à suplementação com mistura mineral. O milho desintegrado com palha e sabugo e o milho desintegrado com sabugo equivalem ao grão de milho triturado.<br>The effect of corn feeding forms in multiple supplements on performance of finishing steers grazing signal grass (Brachiaria decumbens Stapf) during rainy season was evaluated. Sixteen crossbred steers with initial weight of 384 kg and 18 mo old were distributed to four supplements mineral mix (MM) (control) and three multiple supplements with different feeding forms of corn: ground corn (GC); ground ear-corn (GEC) and ground whole-plant corn (GWPC) - in a completely randomized experimental design with four replicates. The animals were kept in pasture, 6 ha of signal grass, divided into four paddocks of 1.5 ha, with total dry matter and potentially digestible dry matter availabilities of 4.77 t/ha and 3.14 t/ha, respectively. Four esophagus, rumen and abomasum fistulated crossbred animals with initial weight of 390 kg, were used to evaluate the nutritional parameters. Animals were distributed to a 4 &#215; 4 Latin square, composed of four supplements and four experimental periods. The animals in the control group were fed daily with 60 g/day of MM, while the others were fed with 1.0 kg/day of the multiple supplements different. Multiple supplements did not influence the performance of animals, but serum urea concentrations were higher in animals fed with the different multiple supplements. Crude protein and intake and digestibility increased with the use multiple supplements. Animals of the control showed higher dry matter and organic matter intake from the pasture. The different multiple supplements (1 kg/day) promoted numerical increase of up to 165 g/animal/day in relation to control during rainy season. Ground whole-plant corn and ground ear-corn are equivalent to ground corn for steers in the finishing phase in pasture in the rainy season

Influence of life history traits on trophic niche overlap between two similar sympatric Tupinambis lizards

Segregation of habitat resources is an important mechanism that allows the coexistence of species. The diet is an important and dynamic component that can generate interactions among co-existing species. Differences in food resource use between related sympatric species have been associated frequently with divergence in multiple phenotypic traits; hence, it is interesting to explore how phenotypic differences allow sympatric species to minimize niche overlap. We aimed to evaluate trophic niche segregation between Tupinambis merianae and T. rufescensin relation to life history traits in a sympatric zone. We compared the volume of the stomach food items between species considering sexual dimorphism, body size classes, sexual maturity and reproductive activity. The obtained Morisita?s index indicated trophic niche overlap between T. merianaeand T. rufescens; however, considering particular food items, we observed differences in diet composition. Moreover, our results indicate that body size, sexual maturity and reproductive activity are relevant factors influencing the diet of these species. Life history traits of these two species of Tupinambisare important because they shape diet composition, contributing to interspecific segregation of the trophic niche and, therefore, allowing species coexistence.La segregación de los recursos del hábitat es un importante mecanismo que permite la coexistencia de especies. La dieta es un componente importante y dinámico, que puede generar interacciones entre especies co-existentes. Las diferencias en la dieta entre especies relacionadas en simpatría han sido frecuentemente asociadas a la divergencia en múltiples caracteres fenotípicos, por lo tanto es interesante explorar cómo las diferencias fenotípicas permiten que las especies simpátricas minimicen la superposición del nicho. Nuestro objetivo fue evaluar la segregación del nicho trófico entre Tupinambis merianae y T. rufescens en una zona de simpatría y entender de qué manera los caracteres de historia de vida podrían influenciar la ecología trófica de estos lagartos. Analizamos el contenido estomacal comparando el volumen de presas consumidas entre especies, considerando además el dimorfismo sexual, las clases de tamaño corporal, la madurez sexual y la actividad reproductiva. El índice de Morisita obtenido indica superposición del nicho trófico entre T. merianae y T. rufescens, pero considerando algunas presas en particular, observamos que las especies muestran diferencias en la composición de la dieta. Por otro lado, nuestros resultados indican que el tamaño corporal, la madurez sexual y la actividad reproductiva son factores relevantes que influyen en la dieta de las especies. Los caracteres de historia de vida de estas dos especies de Tupinambis son importantes porque determinan la composición de la dieta, contribuyendo a la segregación interespecifica del nicho trófico y en consecuencia a la coexistencia de las especies.Fil: López Juri, Guadalupe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Naretto, Sergio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Mateos, Ana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Chiaraviglio, Margarita. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; ArgentinaFil: Cardozo, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Diversidad y Ecología Animal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto de Diversidad y Ecología Animal; Argentin

Levels of ground corn supplied to beef heifers at pasture during the rainy season: productive performance, intake, digestibility and microbial efficiency

The objective was to evaluate the effect of four levels of ground corn supply on nutritional parameters, microbial synthesis efficiency and growing performance of beef heifers, at the rainy season. For such, 28 crossbred yearling heifers, with initial age of 16-17 months and initial weight of 255 ± 31.0 kg were distributed into five paddoks of B. decumbens, of 2.0 ha each, with average potentially digestible DM availability of 2,377.0 kg/ha. For each one of the lots, one of the following supplements was daily supplied: mineral mix exclusively or with ground corn at levels 0.25, 0.50, 0.75 or 1.00 kg/day. The experiment was arranged in completely randomized design with five treatments (supplements), five repetitions for the groups receiving exclusive mineral mix or mineral mix plus corn on the level of 0.50 kg/day and six repetitions for those receiving the other supplements. There was a response of 0.092 kg of weight gain for every 1 kg of ground corn supplied to the animals, and no substitution effect was verified on the dry matter intake of pasture. The increase in ground corn levels increased metabolizable energy intake, which is explained by the crescent linear effect on digestible dry matter intake, on apparent digestibility of dry matter and organic matter as well as on the levels of total digestible nutrients of the diet consistent with the increase in intake of the most digestible ingredient, ground corn. In the same way, there was a positive linear effect for apparent digestibility of neutral detergent fiber. The supplementation provided linear positive effect on the flow of microbial nitrogen compounds (MICN) for the small intestine, and did not affect the microbial synthesis efficiency. The supply of energetic supplement for beef heifers, at pasture, during the rainy season increases the use of the forage and consequently, weight gain