Forage stockpiling and supplemented cattle: nutritional value, ingestive behavior and animal production during the dry season

Pastos têm sua produção influenciada pelo clima tropical, fazendo-os produzir capim de baixa qualidade e escasso na época da seca. Neste contexto, os animais produzem menos. A vedação de pastos pode minimizar este problema, sendo feita no final da estação de águas e utilizada na seca, preferencialmente com suplementação. As características do pasto vedado influenciam no comportamento ingestivo de animais suplementados. Implantou-se a pesquisa na USP/FZEA em área experimental com 16 piquetes de 1,5 ha, formados por Marandu. O experimento foi fatorial 2 x 2, com 4 tratamentos: altura de vedação (10 ou 20 cm) e 2 níveis de suplementação (0,3 ou 0,6% do peso corporal = %PC), delineados em blocos casualizados e quatro repetições. Para avaliar o comportamento ingestivo foram utilizadas três técnicas: observação visual, gravação de áudio e a bromatologia da simulação de pastejo, taxa de lotação (TL), ganho médio diário (GMD) e ganho de peso total. Baixa suplementação em pastos vedados a 10 cm estimulou os animais a se deslocarem mais, a mastigarem mais vezes a dieta e, ainda, permanecerem por menos tempo na estação de pastejo, quando comparados àqueles vedados a 20 cm, principalmente no período da tarde. Os animais foram mais eficientes em seus bocados, quando estavam em pastos vedados a 10 cm. Animais suplementados a 0,3% do PC tiveram menor tempo de pastejo no início do ciclo, porém maior tempo de ruminação. Ao final do ciclo, ruminaram por menos tempo. Os que receberam 0,6 %PC, tiveram comportamento contrário. Já os que estavam a 20 cm, independentemente da suplementação, os que estavam em pastos vedados a 20 cm, aumentaram o tempo em ruminação. Animais tiveram mais tempo de ócio quando foram mais suplementados e, também, no mês de setembro. Nas amostras de simulação de pastejo, onde os animais receberam maior suplementação (0,6 %PC) continham maiores teores de PB e FDA, sem diferença nos de FDN. A altura de vedação não diferiu em relação a PB, mas a 10 cm, os teores de FDN e FDA eram menores. Em setembro, os pastos apresentaram mais PB e menos FDN e FDA, invertendo seus teores no final do pastejo. A DIVMS teve comportamento inverso ao LDA. Pastos vedados a 10 cm e com animais suplementados a 0,3% do PC, apresentaram-se mais digestíveis no início da estação de pastejo. O mesmo comportamento foi observado naqueles com 0,6% PC apenas no final do ciclo de pastejo. A TL aumentou no decorrer dos meses nos pastos vedados a 10 cm e com animais suplementados a 0,3% PC. O GMD e o ganho de peso total foram superiores nos pastos vedados a 10 cm, ou naqueles que os animais recebiam maior nível de suplementação ou no meio do ciclo de pastejo. A interação entre os fatores propostos causam alterações no comportamento ingestivo dos animais.Pastures have their production influenced by the tropical climate, that makes their production of grass with lower quality and threatened during the dry season. In this context, animals weight gains lower too. Sealing the pastures can minimize this problem, being done at the end of the water season to be used during the dry season, preferably with supplementation. The characteristics of the sealed pasture influence the ingestive behavior of supplemented animals. A research at USP / FZEA was implemented in an experimental area with 16 paddocks of 1.5 ha, formed by Marandu palisade grass. The experiment was a 2 x 2 factorial, with 4 treatments: sealing height (10 or 20 cm) and 2 supplementation levels (0.3 or 0.6% of body weight = % BW), outlined in randomized blocks and four repetitions. To evaluate the ingestive behavior, three techniques were used: visual observation, audio recording and grazing simulation bromatology, stocking rate (SR), average daily gain (ADG) and total weight gain. Lower supplementation in 10 cm sealed pastures stimulated the animals to move more, chew the diet more often, and still stay for less time in the grazing season, when compared to those sealed at 20 cm, especially in the afternoon. The animals were more efficient in their mouths, when they were in sealed pastures at 10 cm. Animals supplemented with 0.3% of BW had a shorter grazing time at the beginning of the cycle, but a longer rumination time. At the end of the cycle, they ruminated for less time. Those who received 0.6% BW had the opposite behavior. Those who were at 20 cm, regardless of supplementation, those who were on closed pastures at 20 cm, increased the time in rumination. Animals had more leisure time when they were supplemented more and in the month of September. In the grazing simulation samples, where the animals received greater supplementation (0.6% BW), they contained higher levels of crude protein (CP) and Acid Detergent Fiber (ADF), with no difference in Neutral Detergent Fiber (NDF). The sealing height did not differ in relation to PB, but at 10 cm, the contents of NDF and FDA were lower. In September, pastures showed more CP and less NDF and ADF, inverting their levels at the end of grazing. Digestibility of Dry Matter had the opposite behavior to lignin (LDA). Pastures sealed at 10 cm and with animals supplemented at 0.3% of CP, were more digestible at the beginning of the grazing season. The same behavior was observed in those with 0.6% BW only at the end of the grazing cycle. SR increased over the months in pastures sealed at 10 cm and with animals supplemented at 0.3% BW. ADG and total weight gain were higher in pastures sealed at 10 cm, or in those that the animals received a higher level of supplementation or in the middle of the grazing cycle. The interaction between the proposed factors causes changes in the animals\' ingestive behavior

Digestibilidade de dietas contendo glicerina para novilhas Nelore confinadas

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Digestibility of diets with glycerin for Nellore heifers in feedlot

The research for not pollutants and renewable sources of energy, made the biodiesel is reused. But, its production generates the “Glycerin” (10% of biodiesel volume). This production is increasing and accumulating year by year, like other industrious by-products. With no law about discarding, scientists started to feed animals in different species with it. Rich in glycerol, it gives energy for animals and doesn't have other nutrients. It improves the alimentary conversion and does not change ruminal ambient or carcass production. For ruminants is used glycerin originated just from vegetables. This experiment aimed to discover what glycerin’s level can be used on diet. Made at the Unesp University of Campus of Jaboticabal, were used 24 heifers of Nellore in feedlot, weight of ± 265 kg in individuals stalls for 112 days. Were used three crossbreed cattle (Angus x Nellore) castrated and cannulated, with ± 400 kg of weight for incubation. The “blond glycerin” used has 83% of glycerol. The proportion of Forage: Concentrate was 30:70. Corn silage was the forage. The concentrate was composed of: soy hulls, sunflower meal, urea and corn or corn more glycerin. All treatments had same percentages of protein and energy and were identified as “without glycerin” (G0), “with 10% of glycerin” (G10) and “20% of glycerin inclusion” (G20) in the dry matter of diet. Samples of food, leavings and excrements were collected. The collections of excrements were made at the superior part of them, without contact with the floor, at the moment of defecation for three consecutive days. Leavings and food were collected just before feeding. Bromatologics analyses were made according AOAC (1995), VAN SOEST and WINE (1967), HENDRIX (1993) and the digestion was made in autoclave (0,5 Kgf/cm2, 111ºC for 50 minutes), proceeding adapted of PELL and SCHOFIELD (1992). ADFi was used as indicator. Incubation was made according to CASALI et al. (2008) for 240 hours and new bromatologics analyses were made. The dry matter, organic matter, fat, starch, crude protein and ADF do not suffered any alteration. The digestibility’s coefficients of dry matter and organic matter are similar, so the embers do not changed the digestion of the three diets. The neutral detergent fiber (NDF) had a reduction of its digestibility from 62,47 to 52,14% for (reduction of 16,5%). The hemicellulose (HEM) suffered reduction of 12,56%, from 71,14 to 62,20%, both percentages when diet G0 and G20 are compared D’AUREA (2010) obtains similar data using NDFi. The growing utilization of sunflower meal that contains lignified fibers may have contributed to these results. The inclusion until 10% of “blond glycerin” in the dry matter of a diet does not affect the digestibility's coefficients at these conditions. With 20% of inclusion it had a reduction at it’s the digestibility of NDF and HEM. The glycerin can be utilized on diets as a part of the concentrate, been the energy part of diets to Nellore heifers