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Flint corn processing method [coarse ground corn (CGC; 3.2 mm average particle size) or steam-flaked corn (SFC; 0.360 kg/L flake density)] was evaluated in conjunction with 4 levels of NDF from sugarcane bagasse (SCB) as roughage source (RNDF; 4%, 7%, 10%, and 13%; DM basis) to determine impact on growth performance, carcass characteristics, starch utilization, feeding behavior, and rumen morphometrics of Bos indicus beef cattle. Two hundred and forty Nellore bulls were blocked by initial BW (350 ± 37 kg), assigned to 32 feedlot pens and pens within weight block were randomly assigned, in a 2 × 4 factorial arrangement (2 corn processing and 4 levels of RNDF) to treatments. Effects of corn grain processing × RNDF level were not detected (P ≥ 0.14) for growth performance, dietary net energy concentration, carcass traits, rumen morphometrics, and feeding behavior, except for time spent ruminating and time spent resting (P ≤ 0.04), and a tendency for papillae width (P ≤ 0.09). Bulls fed SFC-based diets consumed 7% less (P = 0.001), had 10.6% greater carcass-adjusted ADG (P < 0.001) and 19% greater carcass-adjusted feed efficiency (P < 0.001) compared with bulls fed CGC-based diets. Observed net energy for maintenance and gain values were 14.9% and 19.4% greater (P < 0.001), respectively, for SFC than for CGC-based diets. Fecal starch concentration was less (P < 0.001) for bulls fed SFC compared with those fed CGC. No grain processing effects were detected (P = 0.51) for rumenitis score; however, cattle fed SFC presented smaller ruminal absorptive surface area (P = 0.03). Dry matter intake increased linearly (P = 0.02) and carcass-adjusted feed efficiency tended (P = 0.06) to decrease linearly as RNDF increased. Dietary RNDF concentration did not affect carcass characteristics (P ≥ 0.19), except for dressing percentage, which tended to decrease linearly (P = 0.06) as RNDF in finishing diets increased. Increasing RNDF in finishing diets had no effect (P = 0.26) on time spent eating, but time spent ruminating and resting increased linearly (min/d; P < 0.001) with increased dietary RNDF. Steam flaking markedly increased flint corn energy value, net energy of diets, and animal growth performance, and led to improvements on feed efficiency when compared with grinding, regardless of RNDF content of diets. Increasing dietary RNDF compromised feedlot cattle feed efficiency and carcass dressing.

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Greenhouse gases emissions are considered one of the most important environmental issues of dairy farming systems. Nitrous oxide (N2O) has particular importance owing to its global warming potential and stratospheric ozone depletion. The objective of this study was to investigate the influence of two rotational grazing strategies characterized by two pre-grazing targets (95% and maximum canopy light interception; LI95% and LIMax, respectively) on milk production efficiency and N2O fluxes from soil in a tropical dairy farming system based on elephant grass (Pennisetum purpureum Schum. cv. Cameroon). Results indicated that LI95% pre-grazing target provided more frequent defoliations than LIMax. Water-filled pore space, soil and chamber temperatures were affected by sampling periods (P1 and P2). There was a significant pre-grazing target treatment × sampling period interaction effect on soil NH4+ concentration, which was most likely associated with urinary-N discharge. During P1, there was a greater urinary-N discharge for LI95% than LIMax (26.3 vs. 20.9 kg of urinary-N/paddock) caused by higher stocking rate, which resulted in greater N2O fluxes for LI95%. Inversely, during P2, the soil NH4+ and N2O fluxes were greater for LIMax than LI95%. During this period, the greater urinary-N discharge (46.8 vs. 44.8 kg of urinary-N/paddock) was likely associated with longer stocking period for LIMax relative to LI95%, since both treatments had similar stocking rate. Converting hourly N2O fluxes to daily basis and relating to milk production efficiency, LI95% was 40% more efficient than LIMax (0.34 vs. 0.57 g N-N2O/kg milk·ha). In addition, LI95% pre-grazing target decreased urea-N loading per milk production by 34%. Strategic grazing management represented by the LI95% pre-grazing target allows for intensification of tropical pasture-based dairy systems, enhanced milk production efficiency and decreased N-N2O emission intensity.

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Abstract Background: Production of heart-of-palm from Alexander palm tree generates a waste that could be used as silage for feeding ruminants. Objective: To evaluate the chemical composition, fermentation parameters, and quality of silage made from waste of heart-of-palm production using Alexander palm. Methods: Three types of silage made from waste of heart-of-palm production were evaluated: 1) leaf silage, 2) sheath silage, and 3) compound (leaf + sheath) silage. The processed waste was packed in experimental silos and distributed in a completely randomized design with 10 replications. Means were compared pairwise using Tukey's test at the 5% significance level. Results: Leaf silage had the highest pH (p<0.05) and the lowest ammonia nitrogen (p<0.05) in relation to the other silages. No difference was observed (p>0.05) for lactic and butyric acids, whereas acetic acid was higher (p<0.05) in the sheath and compound silages. Dry matter and crude protein contents were the highest (p<0.05) in leaf silage. Neutral detergent fiber was higher (p<0.05) in sheath silage, followed by leaf and compound silages, respectively. The highest lignin content (p<0.05) was observed in sheath silage. Conclusions: Based on the fermentative parameters, waste from heart-of-palm from Alexander palm tree has potential for silage production. However, differences in silage composition at the time of feeding ruminants should be considered.

Resumen Antecedentes: Los residuos de la producción de palmito de Palma Real podrian utilizarse como ensilaje para alimentación de rumiantes. Objetivo: Determinar la composición, parámetros químicos de fermentación, y calidad del ensilaje elaborado a partir de residuos procedentes de la producción de palmito de Palma Real. Métodos: Tres tipos de ensilaje hechos con los residuos generados a partir de la producción de palmito fueron evaluados: 1) ensilaje de hojas, 2) ensilaje de vainas, y 3) ensilaje compuesto (hojas + vainas). Los residuos tratados fueron empacados en silos experimentales y distribuidos en un diseño completamente al azar con 10 repeticiones. Las medias fueron comparadas mediante la prueba de Tukey, con un nivel de significancia del 5%. Resultados: El ensilaje de hojas mostró el pH más alto (p<0,05) y el nivel más bajo de nitrógeno amoniacal (p<0,05) en comparación con los otros ensilajes. No se observaron diferencias (p>0,05) en los ácidos láctico y butírico, mientras que el ácido acético fue mayor en el ensilaje de vainas y en el compuesto en relación con el otro ensilaje. La materia seca (MS) y el contenido de proteína cruda (PC) fueron mayores (p<0,05) en el ensilaje de hojas. Los contenidos de fibra detergente neutra fueron mayores (p<0,05) en los ensilajes de vainas, seguido por los ensilajes de hojas y compuesto, respectivamente. El contenido de lignina fue más alto (p<0,05) en el ensilaje de vainas. Conclusiones: Según los parámetros fermentativos, los residuos de la producción de palmito de Palma Real tienen potencial para la producción de ensilaje. Sin embargo, se deben considerar las diferencias en la composición de los ensilajes al momento de alimentar rumiantes.

Resumo Antecedentes: Resíduos da produção de palmito da palmeira Real são um problema para a agroindústria devido sua falta de utilização e o seu uso na forma de silagem pode ser uma alternativa na alimentação de ruminantes. Objetivo: Avaliar a composição química e os parâmetros fermentativos, e verificar a qualidade da silagem produzida a partir do resíduo da produção de palmito da Palmeira Real Australiana. Métodos: Foram avaliadas três tipos de silagem de resíduo da produção de palmito da Palmeira Real: silagem de folha, silagem de bainha e silagem da composta (folha + bainha). O resíduo processado foi acondicionado em silos experimentais e distribuídos em um delineamento inteiramente casualizado com 10 repetições e as médias comparadas pelo teste de Tukey a 5% de significância. Resultados: A silagem de folha apresentou maior pH (p<0,05) em relação as demais silagens, enquanto para o nitrogênio amoniacal (p<0,05), apresentou menor teor em relação as demais silagens. Não observou-se diferença (p>0,05) para os ácidos lático e butírico, enquanto o ácido acético foi maior para as silagens de bainha e composta em relação as demais silagens. O teor de matéria seca (MS), proteína bruta (PB) foi maior (p<0,05) na silagem de folha em relação as demais silagens. A fibra em detergente neutro analisada estimada apresentou maiores valores (p<0,05) para a silagem de bainha, seguida pela silagem de folhas e silagem composta, respectivamente. O teor de lignina foi maior (p<0,05) para a silagem de bainha. Conclusões: De acordo com os parâmetros fermentativos, os resíduos da produção de palmito da Palmeira Real apresentam potencial para a produção de silagem. No entanto, as diferenças na composição das silagens devem ser consideradas quando oferecidas para animais ruminantes.

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Two experiments were conducted to evaluate the performance responses of finishing feedlot cattle to dietary addition of essential oils and exogenous enzymes. The treatments in each experiment consisted of (DM basis): MON-sodium monensin (26 mg/kg); BEO-a blend of essential oils (90 mg/kg); BEO+MON-a blend of essential oils plus monensin (90 mg/kg + 26 mg/kg, respectively); BEO+AM-a blend of essential oils plus exogenous α-amylase (90 mg/kg + 560 mg/kg, respectively); and BEO+AM+PRO-a blend of essential oils plus exogenous α-amylase and exogenous protease (90 mg/kg + 560 mg/kg + 840 mg/kg, respectively). Exp. 1 consisted of a 93-d finishing period using 300 Nellore bulls in a randomized complete block design. Animals fed BEO had higher DMI (P < 0.001) but similar feed efficiency to animals fed MON (P ≥ 0.98). Compared with MON, the combination of BEO+AM resulted in 810 g greater DMI (P = 0.001), 190 g greater average daily gain (P = 0.04), 18 kg heavier final body weight (P = 0.04), and 12 kg heavier hot carcass weight (P = 0.02), although feed efficiency was not significantly different between BEO+AM and MON (P = 0.89). Combining BEO+MON tended to decrease hot carcass weight compared with BEO alone (P = 0.08) but not compared with MON (P = 0.98). Treatments did not impact observed dietary net energy values (P ≥ 0.74) or the observed:expected net energy ratio (P ≥ 0.11). In Exp. 2, five ruminally cannulated Nellore steers were used to evaluate intake, apparent total tract digestibility of nutrients, and ruminal parameters in a 5 × 5 Latin square design. Feeding BEO increased the total tract digestibility of CP compared to MON (P = 0.03). Compared to MON, feeding the combination of BEO+MON increased the intake of CP (P = 0.04) and NDF (P = 0.05), with no effects on total tract digestibility of nutrients (P ≥ 0.56), except for a tendency (P = 0.09) to increase CP digestibility. Intakes of all nutrients measured, except for ether extract (P = 0.16) were greater in animals fed BEO+AM when compared with MON (P ≤ 0.03), with no differences on total tract nutrient digestibilities (P ≥ 0.11) between these two treatments. In summary, diets containing the BEO used herein enhanced DMI of growing-finishing feedlot cattle compared with a basal diet containing MON without impair feed efficiency. A synergism between BEO and AM was detected, further increasing cattle performance and carcass production compared to MON.

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Agricultural systems are responsible for environmental impacts that can be mitigated through the adoption of more sustainable principles. Our objective was to investigate the influence of two pre-grazing targets (95% and maximum canopy light interception during pasture regrowth; LI95% and LIMax, respectively) on sward structure and herbage nutritive value of elephant grass cv. Cameroon, and dry matter intake (DMI), milk yield, stocking rate, enteric methane (CH4) emissions by Holstein × Jersey dairy cows. We hypothesized that grazing strategies modifying the sward structure of elephant grass (Pennisetum purpureum Schum.) improves nutritive value of herbage, increasing DMI and reducing intensity of enteric CH4 emissions, providing environmental and productivity benefits to tropical pasture-based dairy systems. Results indicated that pre-sward surface height was greater for LIMax (≈135 cm) than LI95% (≈100 cm) and can be used as a reliable field guide for monitoring sward structure. Grazing management based on LI95% criteria improved herbage nutritive value and grazing efficiency, allowing greater DMI, milk yield and stocking rate by dairy cows. Daily enteric CH4 emission was not affected; however, cows grazing elephant grass at LI95% were more efficient and emitted 21% less CH4/kg of milk yield and 18% less CH4/kg of DMI. The 51% increase in milk yield per hectare overcame the 29% increase in enteric CH4 emissions per hectare in LI95% grazing management. Thereby the same resource allocation resulted in a 16% mitigation of the main greenhouse gas from pasture-based dairy systems. Overall, strategic grazing management is an environmental friendly practice that improves use efficiency of allocated resources through optimization of processes evolving plant, ruminant and their interface, and enhances milk production efficiency of tropical pasture-based systems.

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