Embora ruminantes aproveitem fibras dos alimentos, a degradação varia de acordo com a composição físico-química. Enzimas fibrolíticas tem sido utilizadas para aumentar a degradação ruminal de fibras, podendo otimizar o aproveitamento dos nutrientes. O objetivo deste estudo foi avaliar o efeito da enzima fibrolítica xilanase e de um blend enzimático contendo xilanase, celulase e glucanase, em alimentos volumosos: feno de alfafa (Medicago sativa), capim-Braquiária (Urochloa ruziziensis syn Brachiaria ruziziensis) cana-de-açúcar (Saccharum officinarum), capim-Mombaça (Megathyrsus maximus syn Panicum maximum cv. Mombaça) e silagem de milho (Zea mays). O delineamento experimental foi inteiramente casualizado com 5 repetições (vacas), para cada tratamento. Os tratamentos consistiram em uma pré-incubação por 12 horas em tampão de McDougall: 1) sem a adição de enzimas (CT); 2) com a adição de 200 mg/kg de matéria seca (MS) de amostra (XI); e com a adição de 200 mg/kg de MS de amostra (BL). Após a aplicação dos tratamentos, as amostras dos alimentos foram incubadas no rúmen das vacas, por 96 horas. O capim-Mombaça apresentou maiores degradações da MS e FDN que as demais forrageiras avaliadas. A xilanase tendeu a aumentar a degradação da fibra em detergente ácido (FDA) em relação ao controle. O blend enzimático aumentou a degradabilidade da MS e FDN, em relação à CT e tendeu a aumentar a degradação da MS e da FDN em relação à XI. A adição do blend enzimático aumenta a degradação da MS e FDN, sendo uma estratégia enzimática recomendada na dieta de ruminantes.

This study determined whether Canopeo and GreenSeeker measurements in Megathyrsus maximus can estimate plant height, dry matter mass, morphological components, and content of crude protein and neutral detergent fiber at different days of growth. Five plots of 5 × 25m M. maximus grass were defined: subplots of 1×1m were evaluated every three days, in which the pasture shows 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 days of regrowth. The subplot was evaluated for canopy height and mass accumulation. The canopeo index (CI) obtained at a higher height was lower than those obtained at a smaller height. Higher measurement height increased the normalized difference vegetation index (NDVI) relative to 0.10 m. The highest indexes were observed since 18 d of regrowth. Except for the CI evaluated at 0.10 m of height, the indexes were not correlated to the chemical composition of the forage. The CI and NDVI were positively correlated to plant height, dry matter mass, and leaf index, whereas both were negatively correlated with stalk index. Thus, lower evaluation heights for CI and NDVI can be a good predictor of forage height. Values of 0.83 and 85.8 for NDVI and CI, respectively, indicated an appropriate time to start the grazing of M. maximus.

The present study aims to evaluate the nutritional value of different tree and shrub leaves in Brazilian ruminant production systems. Eight potentially edible trees and shrubs were identified from interviews with 30 ruminant producers: Aroeira (ARO; Lithraea molleoides), Black Mulberry (BMU; Morus nigra), Candeia (CAN; Eremanthus erythropappus), Jatobá (JAT; Hymenaea courbaril), Gliricídia (GLI; Gliricidia sepium), Santa Bárbara tree (SBT; Mélia azedarach), Tithonia (TIT; Tithonia diversifolia), and White Mulberry (WMU; Morus alba). Four leaf samples of each edible tree were sampled, and chemical analyses and in vitro assays were performed. Edible trees (except CAN and JAT) had lower neutral detergent fiber content than Mombasa grass. In addition, SBT, BMU, WMU, and TIT had lower fiber content than the other evaluated edible trees. Consequently, SBT, TIT, BMU, and WMU had improved dry matter degradation. Among the edible trees and shrubs, SMW and WMU increased the potential for gas production (a parameter). On the other hand, CAN decreased the estimated gas production 48 h after incubation. Furthermore, TIT decreased methane production up to 24 h after in vitro fermentation. Thus, except ARO, CAN, and JAT, the edible trees evaluated in the present study are potential feeds in moderate- to high-producing animals. Additionally, TIT fermentation reduces in vitro methane production.

Ensilage of rehydrated corn kernels (RC) has been used to improve nutritional value and facilitate on-farm storage. This study evaluated the effects of chitosan and lactic acid microbial inoculants on rehydrated corn silage microbiology, fermentation profile and losses, chemical composition, in vitro degradation, and aerobic stability. Forty experimental silos were used in a completely random design to evaluate the following treatments: 1) Control (CON): RC silage without additives; 2) Chitosan (CHI): RC silage with 6 g/kg dry matter (DM) of chitosan; 3) Lactobacillus buchneri (LB): RC ensiled with 5 × 10⁵ colony forming units (CFU) of L. buchneri per gram fresh weight; and 4) Lactobacillus plantarum and Pediococcus acidilactici (LPPA): RC ensiled 1.6 × 10⁵ of L. plantarum and 1.6 × 10⁵ P. acidilactici per gram fresh weight. Additives increased lactic acid bacteria and concentration of lactic and propionic acid, decreased mold and yeast count and gas and fermentative losses, and improved DM recovery. The CHI-silos had lower silage pH, Ammonia-N concentration, fermentative losses, and higher acetic acid concentration compared to microbial inoculated-silos. In addition, CHI and LB decreased silage pH and temperature after aerobic exposure. Although, treatments showed slight effects on the nutritional value of RC, CHI improved aerobic stability and decreaseds fermentation losses.

This study aimed to evaluate rice bran (RB) and microbial inoculation effects on pearl millet silage fermentative losses, fermentation profile, nutrients recovery, chemical composition, in vitro degradation and aerobic stability. Seventy‐two experimental silos (PVC buckets with 28 cm diameter and 25 cm height) were used to evaluate nine treatments, from a 3 × 3 factorial arrangement: (I) levels of RB: 0, 100 and 200 g/kg as‐fed; and (II) microbial inoculation: (1) Control (CON): no inoculation; (2) LPPP: inclusion 1.04 × 10 ⁵ colony forming units (CFU) of Lactobacillus plantarum and 1.04 × 10 ⁵ CFU of Pediococcus pentosaceus per g; and (3) LB: inclusion 1.6 × 10 ⁵ CFU of Lactobacillus buchneri per g. The silage microbial inoculant inclusion had no effect on silage, regardless of RB addition. Rice bran increased silage pH and decreased ammonia‐N, propionic, butyric and branched‐chain fatty acids content. Rice bran decreased gas losses and recovery of DM, OM, CP and ADF, whereas increased digestible DM recovery. The addition of RB reduced OM, NDF, ADF and ADL silage content, and increased silage DM, CP and EE, and NDF degradation. Therefore, RB increases digestible DM recovery, and improves silage fermentation and nutritional value.