Luiz Fernando Costa e Silva

Degradação ruminal e digestibilidade intestinal da proteína bruta de alimentos para bovinos

The objective of the present study was to determine the A and B fractions and the rumen degradation rate (Kd) of dry matter (DM) and crude protein (CP) in 27 feeds and determine the intestinal digestibility of non-degraded rumen protein by the three steps and mobile nylon bag techniques. Rice meal, babassu meal, wheat and corn germ, ground corn cobs and straw, ground corn cobs, corn, citrus pulp, sorghum, starea and cottonseed meal with 28, 38 and 46% CP, peanut meal, sunflower meal, soybean meal, bean byproduct, corn gluten, soybean grain, dry yeast, corn gluten meal, cacao hulls, coffee hulls, soybean hulls, elephant-grass silage and corn silage were sampled. To obtain the ruminal degradation of DM and CP, 10 × 20 cm nylon bags with incubation times of 0, 2, 4, 6, 12, 16, 24, 48 and 72 hours were used. The intestinal digestibility was determined by the three steps and the mobile nylon bag techniques. The ruminal degradation data of the dry matter and crude protein were similar to the literature. The three step technique did not estimate properly the intestinal digestibility of all the feeds evaluated, excepted for the protein feeds. Most feeds had total CP digestibility close to 90%, excepted for soybean, coffee and cacao hulls and elephant-grass and corn silage. The three step technique correctly estimated the intestinal digestibility of the protein feeds, but the equation IDCP (%) = -5,1906 + 1,1053 × X is recommended to correct the digestibility obtained by the three steps technique for non-protein feeds.

Creatinine excretion and relationship with body weight of Nellore cattle

The objective of this study was to estimate the urinary creatinine excretion by the shrunk body weight (SBW). In experiment I, 32 Nellore bulls with initial body weight of 259±24.9 kg and 14±1 months-old were used. The group was divided in four animals to maintenance and twenty eight animals feeding ad libitum and separated in four groups; each group was slaughtered at different times of feedlot (42, 84, 126 and 168 days). The diet was composed of corn silage and concentrate (55:45). Before the slaughters, the total urinary collection was realized during three days. A database of creatinine excretion was collected from other five studies that had been conducted with Nellore cattle. In all the studies, the total urinary collection was realized during at least three days. At the end of each collection, the animals were weighted. Urinary creatinine excretion (UCE) was related with the shrunk body weight and it can be estimated by the equation: UCE (g/day) = 0.0345 × SBW0.9491.

Consumo, digestibilidade total, produção de proteína microbiana e balanço de nitrogênio em dietas com subprodutos de frutas para ruminantes

The objective of this study was to evaluate the effects of inclusion of by-product of fresh fruit (pineapple, guava, papaya, mango and passion fruit) used in the diet for bovines partly replacing corn silage on intake and total nutrient digestibility, on the production of microbial protein and the nitrogen balance and on prediction of digestible fractions and total digestible nutrients (TDN) of these by-products. All animals received corn silage and the urea/ammonium sulfate (9:1) mixture so diets would remain isonitrogenous. The intakes of dry matter (DM) (kg/day), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF) and TDN, and the digestibility of CP, non-fibrous carbohydrates (NFC) and ether extract (EE) were affected by the source of the by-product. There was an effect for the level of inclusion of products in the digestibility of CP and EE. The by-products of papaya, mango and pineapple showed energy values of 23.1, 18.0 and 7.1% respectively, higher than corn silage. The source of the by-product influenced urinary excretion of derived from total purine, purine absorbed and production of microbial protein, in addition to the intake (g/day), the excretion in feces and urine (g/day) of nitrogen compounds and nitrogen balance (g/day). The level of inclusion of the by-product in the diet affect the urinary excretion of derived from total purine, purine absorbed and microbial protein production. The by-products of pineapple, papaya and mango have energy value higher than corn silage and they can partly replace energy concentrates in diets for ruminants. The by-product of passion fruit has the potential to partly replace roughage in the diets of ruminants. The by-product of guava has use limitations in diets of ruminants.

Esterco líquido de bovinos leiteiros combinado com adubação mineral sobre atributos químicos de um Latossolo Bruno

This study aimed to evaluate the influence of fertilization doses of liquid dairy manure combined with mineral fertilizer on the chemical properties of a Brown Oxisol, in no-tillage system and winter and summer crop rotation (sorghum/black-oat/corn/ryegrass/corn/ryegrass), for silage production, in the layers 0-5, 5-10, 10-30, 30-50 and 50-80 cm. The treatments were distributed in three randomized blocks, divided in 12 plots per block, in a 3 x 4 factorial arrangement, with three mineral fertilizer levels (0, 50 and 100 % of the dose recommended for the crops) and four organic fertilizer levels (0, 30, 60 and 90 m3 ha-1 year-1). The liquid dairy manure increased the pH linearly in the 0-5 cm layer and quadratic in the 30-50 cm layer. The mineral fertilization reduced the pH values linearly in the 0-5 and 5-10 cm layers, with quadratic effect at 50-80 cm. The potential acidity decreased in 5-10 cm, with quadratic pattern at 10-30 cm. The exchangeable Ca2+ increased in the 0-5 cm layer with manure, but no effect of mineral fertilization on this attribute was verified. An increase in exchangeable Mg2+ levels was observed in the manure treatments to a depth of 30 cm; under mineral fertilizer, increases were observed from 30 cm downwards. There was a linear increase of base saturation through manure doses, down to a depth of 10 cm, and the mineral fertilization decreased base saturation at 5-10 cm, with a quadratic effect at 50-80 cm.

Avaliação de indicadores em estudos com ruminantes: estimativa de consumos de concentrado e de silagem de milho por vacas em lactação

Two studies were carried out to evaluate individual dry matter intake of group-fed lactating dairy cows. In the first trial, eight cows were housed in individual pens and fed corn silage and 4 kg of concentrate meal. Two external markers (chromium oxide and titanium dioxide) were used to predict individual concentrate intake. Indigestible acid detergent fiber (iADF) was used to estimate individual silage intake. Fecal dry matter output (FDMO) was determined by total collection and also by LIPE®. Chromium oxide and titanium dioxide were able to estimate individual concentrate intake, regardless of the FDMO method. The iADF marker was able to estimate the individual silage intake. In the second trial, 31 cows were distributed in three groups, housed in a free stall and fed corn silage and concentrate according to milk yield (8.0, 5.5, and 4 kg, for groups 1, 2 and 3, respectively). There was no difference between chromium oxide and titanium dioxide in the estimates of individual concentrate intake which were similar to the observed values (7.12 vs 6.99, 4.96 vs 4.81 and 3.52 vs 3.49 kg/cow/day). Individual intakes of concentrate, silage and total dry matter varied considerably, regardless of the group. There was no relationship among dry matter intake, milk yield and metabolic body weight. Chromium oxide and titanium dioxide and iADF can be used to estimate individual intakes of concentrate and corn silage, respectively, by group-fed lactating dairy cows.

Macrominerals and Trace Element Requirements for Beef Cattle

Eighty-seven Nellore animals were utilized in this study to estimate net requirements for the maintenance and growth of beef cattle as well as the retention coefficients of 13 minerals: macrominerals (Ca, P, Mg, K, Na, and S) and trace elements (Cu, Fe, Mn, Se, Zn, Co, and Cr). The net requirements for maintenance and the true retention coefficient were estimated by using the regression between apparent retention and intake for each mineral. The net requirement for maintenance (μg/kg BW) and retention coefficients (%) were 163 and 85 for Cu, 2,097 and 53 for Fe, 32.3 and 24 for Mn, 3.72 and 48 for Se, 669 and 0.80 for Zn, 18.4 and 86 for Co, and 22.9 and 78 for Cr. The dietary requirements of macrominerals (g/kg DMI) were 5.12 for Ca, 2.38 for P, 0.96 for Mg, 2.40 for K, 0.79 for Na, and 1.47 for S. This is the first study using Nellore cattle to estimate mineral requirements; considering that Nellore cattle are the most common breed in Brazil and that Brazil is a major beef producer globally, this knowledge can help producers to improve animal performance by supplying the correct amount of minerals.

Exigências de energia de animais Nelore puros e mestiços com as raças Angus e Simental

The objective of this work was to estimate the nutritional requirements of net and metabolizable energy of Nellore, Nellore-Angus and Nellore Simmental cattle, as well as the efficiency of utilization of metabolizable energy for gain and maintenance and efficiency of energy deposition in the form of protein and fat. It was used 69 animals (23 Nellore, 23 Nellore-Angus and 23 Nellore-Simmental): four animals from each genetic group (12 in total) were slaughtered before the beginning of the experiment as the baseline group, and nine were used in a digestibility trial. The remaining animals were grouped in three dietary treatments (concentrate fed at 1 or 2% of body weight obtained with ad libitum intake or corresponding to 1% of the maintenance requirement). At the end of the experiment, all animals were slaughtered and body composition and empty body weight (EBW) were determined. The net energy requirements were estimated by using the equation of retained energt as a function of EBW0.75 and empty body weight gain (EBG). It was estimated the requirements of net and metabolizable energy for maintenance by using heat production equation in function of metabolizable energy intake. There was an effect of concentrate contents of the diet on the body weight:EBW ratio, as well as for body weight gain:EBG ratio. The net energy daily requirement for maintenance of Nellore, Nellore-Angus and Nellore-Simmental is 75.8 kcal/EBW0.75 and the metabolizable energy requirements for maintenance are 112.82 kcal/EBW0.75. The efficiency of metabolizable energy utilization for gain and maintenance are 41.22 and 67.17%, respectively, and the energy retention efficiency as protein and fat are 26.71 and 75.43%, respectively.The objective of this work was to estimate the nutritional requirements of net and metabolizable energy of Nellore, Nellore-Angus and Nellore Simmental cattle, as well as the efficiency of utilization of metabolizable energy for gain and maintenance and efficiency of energy deposition in the form of protein and fat. It was used 69 animals (23 Nellore, 23 Nellore-Angus and 23 Nellore-Simmental): four animals from each genetic group (12 in total) were slaughtered before the beginning of the experiment as the baseline group, and nine were used in a digestibility trial. The remaining animals were grouped in three dietary treatments (concentrate fed at 1 or 2% of body weight obtained with ad libitum intake or corresponding to 1% of the maintenance requirement). At the end of the experiment, all animals were slaughtered and body composition and empty body weight (EBW) were determined. The net energy requirements were estimated by using the equation of retained energt as a function of EBW0.75 and empty body weight gain (EBG). It was estimated the requirements of net and metabolizable energy for maintenance by using heat production equation in function of metabolizable energy intake. There was an effect of concentrate contents of the diet on the body weight:EBW ratio, as well as for body weight gain:EBG ratio. The net energy daily requirement for maintenance of Nellore, Nellore-Angus and Nellore-Simmental is 75.8 kcal/EBW0.75 and the metabolizable energy requirements for maintenance are 112.82 kcal/EBW0.75. The efficiency of metabolizable energy utilization for gain and maintenance are 41.22 and 67.17%, respectively, and the energy retention efficiency as protein and fat are 26.71 and 75.43%, respectively.

Using growth and body composition to determine weight at maturity in Nellore cattle

The aim of the present study was to estimate the relationships among water, crude protein (CP), ether extract (EE) and ash in the empty bodyweight (EBW), and the soft tissue and bone and, moreover, to determine an objective method to define weight at maturity in Nellore cattle. A dataset containing carcass and body compositions of 249 animals from 11 experiments was developed. There were 63 bulls, 105 steers, and 81 heifers where all animals were purebred Nellore, aged between zero and 24 months. The contents of water, CP and ash in the EBW were predicted by non-linear regressions, whereas an exponential model was used to predict EE. In addition, the content of CP was predicted on a fat-free dry matter (FFDM) basis, and maturity was defined as the point when no significant accretion of CP in the FFDM was observed. The soft tissue water (STW) was regressed on logistic Gompertz functions, and segmented regression models, whereas the analysis of bone chemical composition in the EBW was conducted using an exponential model. The gender effect was not significant (P > 0.05) for EBW and EE; therefore, this effect was not included in the analysis of FFDM. The exponential model suggests that Nellore cattle reached maturity at ~445 kg and the segmented regression model suggested that maturity was reached at 429 kg. A significant relationship between the concentration of STW and soft tissue EE (STEE) was observed (STEE = 0.920 – 1.147 × STW; r2 = 0.96, mean square error = 1.01), but the soft tissue was not a good predictor of maturity, because it is dependent on the diet. Analysis of bone chemical composition showed that EE, water and ash become constant between 400 and 500 kg of EBW, and that CP in bones was constant at 19.1% of EBW. These data also suggested that bone composition could be a good predictor of maturity; however, with the high variability in our dataset, it was not possible to determine an EBW at which these components became constant with a reliable precision. We concluded that Nellore cattle reach maturity at ~437 kg of EBW and that CP in the FFDM and CP, water and ash in bones are good predictors of maturity, whereas soft tissue composition is not a useful predictor of maturity.

Esterco de gado leiteiro associado à adubação mineral e sua influência na fertilidade de um latossolo sob plantio direto

Dairy cattle in South Brazil is raised mainly in a system based on partial or total confinement of the animals, generating a significant amount of residues. The residues have been used as the only nutrient source or associated to mineral sources in grain or silage production. Their effect on soil characteristics has however been little explored. This study was conducted to evaluate the influence of fertilization rates with liquid dairy cattle manure associated with mineral fertilizer on P, K, C, and electrical conductivity (EC) levels of a Brown Oxisol, under no-tillage and winter and summer crop rotation (sorghum/black-oat/corn/ryegrass/corn/ ryegrass) for silage production, in the layers 0-5, 5-10, 10-30, 30-50 and 50-80 cm. The treatments were distributed in three randomized blocks, each divided in 12 plots, in a 3 x 4 factorial arrangement, with three mineral fertilizer levels (0, 50 and 100 % of the dose recommended for the crops) and four organic fertilizer levels (0, 30, 60, and 90 m3 ha-1 year-1). Mineral fertilizer resulted in higher values of available P (Mehlich-1 and resin) to a depth of 10 cm, due to the fertilizer application in depth by the planter, whereas the highest values under manure surface application were restricted to the 0-5 cm layer. Potassium depletion was observed along the soil profile due to high extraction by silage, and a linear ratio with available K level could be applied in the case of liquid manure at all depths. The lack of effect by the mineral fertilizer on K is probably due to the low rate of K application. A direct relationship was observed between manure rates and organic C concentration in the 0-5 cm layer, unlike in the case of mineral fertilizer. Low EC values were obtained suggesting high nutrient exportation by silage production. Results indicate that there was no significant P migration in the Oxisol profile, even after six years of dairy cattle manure application at high rates, and that K applied via manure and mineral fertilizer is insufficient to maintain the levels of this nutrient in systems where K extraction by silage is high. In these situations, increased levels of organic C are restricted to the soil surface layer in no-tillage and directly related to the manure rate.

Intake, performance, digestibility, microbial efficiency and carcass characteristics of growing Nellore heifers fed two concentrate levels

The objective of this study was to evaluate nutrients and dry matter intake, average daily gain, feed efficiency and digestibility of diets, microbial efficiency, cold carcass yield and basic cuts yields of young Nellore heifers receiving two concentrate levels. Nineteen heifers with initial average weight of 165.6±29.8 kg were used. Three animals were used in a trial to determine the digestibility and microbial efficiency of the two levels of concentrate (225 and 450 g/kgDM) and a treatment with a restricted intake maintenance level. The remaining 16 heifers were confined for 168 days for evaluation of performance and intake, divided into two levels of concentrate. Every 42 days, four animals, two from each concentrate level, were slaughtered to determine carcass characteristics, making a 2 × 4 factorial arrangement. Digestibility and microbial efficiency were not affected by concentrate level or intake level, both for ad libitum and restricted feeding. Heifers fed 450 g/kgDM concentrate diet had greater average daily gain than those fed 225 g/kgDM concentrate. Dry matter intake and feed efficiency did not differ between levels of concentrate. Average daily gain (kg/day), dry matter intake (% body weight/day) and feed efficiency were higher in the first period of feedlot (0-42 days) compared with the other (42 to 168 days). Heifers fed 450 g/kgDM concentrate had greater average daily gain than those fed 225 g/kgDM concentrate.