Tamanho de partícula da forragem em dietas com níveis crescentes de fibra para cabras leiteiras

• Autor(a) principal: Felisberto, Nivea Regina de Oliveira
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1813
• topic: Cinética ruminal; Tamanho de partícula; Lantanídeos; Cabra; Ruminal kinetics; Particle size; Lanthanides; Goat; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

The objective of this work was to evaluate the importance of forage particle size in diets for milk goats. Therefore, it was evaluated the ingestion behavior; the fragmentation of the particles offered, consumed, and contained in compartments of the gastrointestinal tract (rumen, omasum and abomasum)and in the feces; the intake, the digestibility, nitrogen alance; rumen mass; average time of indigestible fraction renewal in the rumen; production and lacteal composition and use efficiency of metabolizable energy of lactating goats. The effects of combination of three particle sizes (2, 5 and 15 cm) and four levels of neutral detergent fiber from the forage (NDFf) (34, 41, 49 and 57% NDFf) were evaluated. Forty-eight multiparous goats at an average of 51 kg of body weight and 60 days of lactation were used. It was used a completely randomized experimental design, in a 3 × 4 factorial scheme with four repetitions. The forage source used was Tifton grass hay (Cynodon dactylon), considered of good quality, containing 62% of NDF and 15% CP, offered in a complete mixture with corn meal and soybean meal based concentrate. Forage particle size influenced feed behavior of the animals, presented a linear effect on the time spent with food ingestion. There was an interaction among particle size and forage fiber level, when it was evaluated the time spent on ingestion per unit of consumed fiber. It was verified the effect of particle size on intake of physically effective DM and NDF. Neutral detergent fiber was also influenced by NDFf. There was no influence of forage particle size on percentage of particles bigger than 1.19 mm, neither on the average geometric diameter (AGD) of the particles contained in rumen compartment and feces. There was an interactive effect among particle size and NDFf on percentage of particles bigger than 1.19 mm and AGD of particles. Forage particle size did not affect dry matter and nutrient intake, originally expressed in grams per day. However, it was observed interaction among particle and NDFf level on the concentration of feed consumed fiber. Particle size influenced in a quadratic manner concentration of lignin consumed in the feed. There was an interactive influence among particle size and NDFf level on the concentration of fiber in the rumen. There was no influence of particle size on digestibility coefficients of dry matter and nutrients, on the balance and use of nitrogen in the organism of the animal; on the average time of renewal of dry matter, NDF or lignin; on lacteal production and composition, except for fat content in the milk, which was influenced by the interaction among particle size and NDFf level and on use efficiency of metabolizable energy. Forage particle size should not be considered as an important factor in formulation of diets for milk goats because of the ability they have on fragment particles into homogenous sizes and because of that they do not cause changes on the intake, on use of the nutrients or animal performance.