O. G. Pereira

Degradação ruminal de silagem de capim-elefante emurchecido ou com diferentes níveis de farelo de cacau

The experiment was conducted to evaluate dry matter (DM), crude protein (CP), and neutral detergent fiber (NDF) ruminal degradation of elephantgrass silages wilted under the sun light for eight hours or with addition of 0, 7, 14, 21, and 28% of cocoa meal (CM) at the ensiling. Samples of each silage type were incubated in the rumen of three Holstein cows for 0, 6, 12, 24, 48, 72, 96, 120, and 144 hours. The CM inclusion reduced the degradation potential of DM, which showed greater values for silages without CM (wilted or non-wilted). The CP and NDF potential degradability showed small variations, with mean values near 80 and 46%, respectively. Considering a passage rate of 5%/h, all silages showed high CP effective degradability (over 55%). Although the ruminal degradation estimate for silages with CM showed a reduction tendency, all silages presented DM and CP potential degradability over 65 and 75%, respectively. The CM addition to elephantgrass can be considered an alternative that offers a fast and abundant availability of nutrients to the ruminal system.

Composição bromatológica e digestibilidade in vitro da matéria seca de silagens de milho e sorgo tratadas com inoculantes microbianos

Avaliaram-se a composicao bromatologica e a digestibilidade in vitro da materia seca (DIVMS) de silagens de milho e sorgo, tratadas ou nao com inoculantes microbianos, em diferentes periodos de fermentacao. Utilizou-se um arranjo fatorial 6 x 2 x 3 (periodos de fermentacao x silagens x inoculantes), em delineamento inteiramente casualizado, para avaliacao dos teores de materia seca (MS) e proteina bruta (PB), e um arranjo fatorial 4 x 2 x 3 para avaliacao dos constituintes fibrosos e da DIVMS, ambos com tres repeticoes. Observou-se os efeitos da interacao periodo de fermentacao ´ silagem ´ inoculante sobre os teores de MS e da interacao inoculante ´ periodo, sobre os teores de PB das silagens. Constatou-se efeito da interacao triplice tambem sobre os teores de fibra em detergente neutro (FDN) e fibra em detergente acido (FDA). Estimaram-se teores minimos de FDN nas silagens de milho tratadas com os inoculantes Silobac e Maize-All, respectivamente, de 52,14 e 50,75%, aos 37,34 e 46,1 dias apos a ensilagem. Quanto a celulose, verificou-se, entre as silagens de milho, menores valores nas silagens tratadas, mas nao foi detectado efeito de inoculante nas silagens de sorgo. Os teores medios de hemicelulose foram influenciados por silagem, periodo e inoculante, registrando-se na silagem de milho (29,8%) valor maior que na de sorgo (28,4%). Houve efeito quadratico do periodo de fermentacao sobre a DIVMS da silagem de milho tratada com os inoculantes Silobac e Maize-All, estimando-se valores maximos de 71,1 e 71,7%, aos 42,29 e 50,3 dias de ensilagem, respectivamente. As DIVMS das silagens de sorgo, no entanto, nao foram influenciadas pelo periodo de fermentacao.

Características fermentativas de silagens de capim-elefante emurchecido ou com adição de farelo de cacau

The experiment was carried out to evaluate the fermentation characteristics of eight hours sun light wilted elephant grass silage in comparison to no sun light exposed silage added by 0, 7, 14, 21, and 28% of cocoa meal during the ensilage process. PVC silos, measuring 0.15m diameter x 0.30m height, were used to ensilage the elephantgrass using a compacting pressure of 500kg/m3. Soluble carbohydrates decreased but pH and N-NH3 increased (P<0.05) as the cocoa meal level increased in the silage. No difference between wilted and no wilted elephantgrass silages was observed for organic acid content. Addition of 0, 7, 14, 21, and 28% of cocoa meal caused an increase of 2.23, 2.48, 3.14, 3.49, and 3.87% of lactic acid contents. Addition of cocoa meal during the ensilage process enhanced fermentation quality of elephantgrass silage.

Effects of dietary nonprotein nitrogen on performance, digestibility, ruminal characteristics, and microbial efficiency in crossbred steers.

Two trials were conducted to evaluate the effects of dietary NPN levels on animal performance, diet digestibility, ruminal characteristics, and microbial efficiency. Experiment 1 was conducted with 24 Holstein x Nellore crossbred steers (350 +/- 20 kg of BW) distributed in 6 blocks to evaluate intake and digestibility of nutrients and performance. The diets consisted of 70% corn silage and 30% concentrate (DM basis) and were formulated to contain 12.5% CP (DM basis). Treatments consisted of 0, 15.5, 31, and 46.5% of dietary N as NPN. There were no treatment differences in the daily intakes of DM (P = 0.47), OM (P = 0.60), CP (P = 0.24), nonfiber carbohydrates (NFC; P = 0.74), or TDN (P = 0.63); however, NDF intake decreased linearly as NPN increased (P = 0.02). Additionally, no effects of NPN were observed on apparent total tract digestibility of DM (P = 0.50), OM (P = 0.53), NDF (P = 0.63), or NFC (P = 0.44). The apparent total tract digestibility of CP increased linearly (P = 0.01), but ADG (1.14 kg/d) was not influenced (P = 0.96) as NPN increased. In Exp. 2, 4 ruminally and abomasally cannulated steers (300 +/- 55 kg of BW) were fed the same diet used in Exp. 1 to evaluate the effects of NPN levels on intake and digestibility of nutrients, ruminal characteristics, and microbial efficiency. There were no differences in the daily intakes of DM (P = 0.22), OM (P = 0.17), CP (P = 0.31), NDF (P = 0.29), or TDN (P = 0.49). However, NFC intake increased linearly (P = 0.02), and there was a quadratic effect (P = 0.01) on intake of ether extract as NPN increased. Ruminal digestibility of CP increased linearly (P = 0.01) with the increase of dietary NPN. There were no differences (P >or= 0.28) in microbial protein synthesis and microbial efficiency among the treatments. The results of these trials suggest that dietary NPN levels (up to 46.5% of total N) can be fed to crossbred steers receiving corn silage-based diets without affecting their growth performance or ruminal protein synthesis.

Consumo, digestibilidade dos nutrientes e parâmetros ruminais em bovinos alimentados com silagem de capim-mombaça

Intake; total and partial digestibilities of nutrients; and ruminal pH and ammonia concentration were evaluated in beef cattle fed Mombaca-grass silage and concentrate at the following proportions: 80:20, 65:35, 50:50, and 35:65, in the dry matter basis. Four Holstein x Zebu steers, with average live weight of 229kg, fitted with ruminal and abomasal canullae, were used. The animals were allotted in a 4x4 latin square design. The intakes of dry matter (DM), organic matter (OM), crude protein (CP), ether extract (EE), and total carbohydrates (kg/day), as well the partials digestibilities of non fibrous carbohydrates (NFC) increased linearly with plateau at the concentrate levels of 54.1, 54.8, 52.9, 62.2, 55.2, and 52.7%. The intakes of others nutrients, except neutral detergent fiber (NDF), and the total apparent digestibilities of DM, OM, and NFC and the partial digestibility of OM increased linearly as the concentrate levels in the diets increased. No differences were found on the intake and the total and partial apparent digestibilities of NDF. The ruminal pH and ammonia concentration presented a quadratic affect in relation to the time of sampling, with maximum register at 2.8 and 3.5 hours after feeding, respectively, corresponding to pH 6.53 and 24.76mg/dL of ammonia.