8 research outputs found
Caracterización de la producción y calidad de semillas de una promoción de especies invernales bajo pastoreo continuo y en clausura
No full textEl raigrás es la principal gramínea anual en las promociones de especies invernales. Su estrategia reproductiva es a través de semillas, las cuales son diseminadas a fines de primavera constituyendo el banco de semillas para el próximo año. El objetivo fue evaluar la producción y calidad de semillas en una promoción química de especies invernales bajo diferentes cargas animales en los años 2015 y 2016. Se evaluó número (NE) y longitud (LE) de espigas, producción de semillas (PS), peso de mil semillas (PMS), pureza (P), energía germinativa (EG), poder germinativo (PG), velocidad germinativa (VG) y viabilidad (V). En el establecimiento El Amanecer (UNLP), se cosecharon inflorescencias de raigrás de una promoción química de especies invernales. Los tratamientos fueron: carga animal alta (CAA), carga animal media (CAM), carga animal baja (CAB) y sin pastoreo (CL). El rodeo experimental estuvo compuesto por terneras Aberdeen Angus. El método de pastoreo implementado fue continuo. No se encontraron diferencias significativas entre tratamientos ni entre años en NE, LE, PMS y P. La PS del año 2015 fue significativamente mayor (p<0,05) que el 2016. A los 30 días post cosecha la EG, PG y VG en 2015 no presentaron diferencias significativas entre tratamientos; a los 90 días la EG y PG de la CL fue significativamente mayor que en CAA y CAB e igual a CAM. En el año 2016, a los 30 días, la EG de la CL fue significativamente mayor (p<0,05) que en CAB pero no se diferenciaron de CAA y CAM mientras que el PG y la VG de la CL fue significativamente mayor que el resto de los tratamientos. A los 90 días no hubo diferencias entre tratamientos en las variables EG, PG y VG. La EG y el PG, al día 90 post cosecha del año 2016 fueron superiores al 2015.La EG y la VG fueron significativamente mayores (p<0,05) en el 2015. Por otro lado, el año 2016 presentó valores mayores de V y PG que el 2015. Los resultados demuestran una gran variabilidad entre años y confirman la estrategia de dormancia de la semilla de raigrás para sobrevivir en el verano y germinar con condiciones climáticas óptimas para su crecimiento. No se verifica un deterioro en la producción y calidad de la semilla por parte del pastoreo con diferentes cargas animales que perjudique la propagación del recurso.Ingeniero AgrónomoUniversidad Nacional de La PlataFacultad de Ciencias Agrarias y Forestale
Calculating Reproductive Performance in Beef Operations: The University of Florida Beef Herds' 2019 Breeding Season
No full textThis publication reviews the basic calculations of reproductive performance and reports the reproductive performance of two University of Florida beef herds. Written by Mario Binelli, Angela M. Gonella-Diaza, Thiago Martins, Cecilia C. Rocha, Felipe A. C. C. Silva, Federico Tarnonsky, Sergio Roskopf, Owen Rae, Danny Driver, Nicolas DiLorenzo, Jose Dubeux, and David Thomas, and published by the UF/IFAS Department of Animal Sciences, May 2021
Calculating Calf Performance in Beef Operations: The University of Florida Beef Herds in the 2019–2020 Calving Season
No full textThis article aims to report the calf performance of two beef herds of the University of Florida, located in north (UF/IFAS NFREC, Marianna) and central Florida (Beef Units, Gainesville). Written by Mario Binelli, Angela M. Gonella-Diaza, Thiago Martins, Cecilia C. Rocha, Felipe A. C. C. Silva, Federico Tarnonsky, Sergio Roskopf, Owen Rae, Danny Driver, Nicolas DiLorenzo, Jose Dubeux, and David Thomas, and published by the UF/IFAS Department of Animal Sciences, February 2022
Modelo de predicción de cobertura vegetal en pastizal de la Depresión del Salado
No full textLa evaluación estructural de los pastizales naturales es un aspecto fundamental para elaborar un diagnóstico y propuestas para su utilización. Para ello se emplean diferentes metodologías. El objetivo fue obtener ecuaciones de predicción de cobertura vegetal total a partir de dos métodos de relevamiento florístico. Los métodos utilizados fueron el de Braun Blanquet (estimativo) y la línea de Canfield (mensurable). En el primero se relevó una superficie de 25 m2 y en el segundo 5 metros lineales ubicados en el mismo cuadrante.Facultad de Ciencias Agrarias y Forestale
Effect of increasing levels of Chlorella spp. on the in vitro fermentation and methane production of a corn silage-based diet
No full textBackground: Generally, the forages used in cow-calf and backgrounding cattle operations have low crude protein and high fiber concentration, limiting animal performance and increasing greenhouse gas emissions. Chlorella spp., a green micro-alga, shows promising potential to provide nutrients, especially nitrogen, to low-protein diets. However, information is limited regarding the effects of Chlorella spp. on the in vitro fermentation and methane (CH4) production of diets. Objective: To evaluate the effects of increasing inclusion levels of algae (Chlorella spp.) on ruminal in vitro fermentation profile and CH4 production of a corn silage-based diet. Methods: Incubations were conducted on three separate days using corn silage and gin trash as substrate (70:30 ratio, respectively). Treatments were control (without algae) and 1, 5, and 10% of algae inclusion in the substrate replacing the basal diet. Ruminal fluid was collected from two ruminally cannulated Angus crossbred steers fed ad libitum a corn silage and gin trash diet. Final pH, concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3-N), in vitro organic matter digestibility (IVOMD), total gas, and CH4 production were determined after 24 h of incubation. Variables were evaluated. using the MIXED procedure of SAS software, and means were compared using orthogonal polynomial contrasts. Results: Algae inclusion linearly increased (p0.05) among algae levels. Molar proportion of VFA and the acetate:propionate ratio was not affected (p>0.05) by increasing algae inclusion. Finally, total gas and CH4 production were not different (p>0.05) among treatments. Conclusion: The inclusion of Chlorella spp. does not modify the ruminal in vitro fermentation profile nor the CH4 production of a corn silage-based diet.Antecedentes: Geralmente, as forrageiras utilizadas em sistemas de criação de bovinos de corte nas fases de cria e recria apresentam baixa concentração de proteína bruta e alta concentração de fibra, limitando a produtividade animal e aumentando o impacto ambiental. Chlorella spp. apresenta características promissoras para fornecer nutrientes, especialmente nitrogênio, em dietas com baixo teor de proteína. No entanto, informações sobre a inclusão de Chlorella spp. na fermentação e produção de metano (CH4) in vitro ainda são escassas na literatura. Objetivo: Avaliar o efeito do aumento da inclusão de algas (Chlorella spp.) no perfil de fermentação in vitro e na produção de CH4 em uma dieta à base de silagem de milho. Métodos: As incubações foram realizadas em três dias diferentes utilizando como substrato silagem de milho e resíduo de algodão (na proporção 70:30, respectivamente). Os tratamentos utilizados foram: controle (sem alga) e três diferentes níveis de inclusão de 1, 5 e 10% alga no substrato. O fluido ruminal foi coletado de dois novilhos Angus canulados no rúmen consumindo silagem de milho e resíduos de algodão ad libitum. O pH final, a concentração de ácidos graxos voláteis (VFA), nitrogênio amoniacal (NH3-N), digestibilidade in vitro da matéria orgânica (IVOMD), produção total de gás e CH4 foram determinados após 24 h de fermentação. As variáveis foram avaliadas utilizando o PROC MIXED do software SAS e as médias comparadas por meio de testes polinomiais ortogonais. Resultados: O aumento dos níveis de algas aumentou linearmente (p0,05) entre os níveis de algas. Além disso, as proporções molares de AGV e a relação acetato:propionato não foram afetadas pelo aumento (p>0,05) na concentração de algas. Adicionalmente, a produção total de gás e CH4 também não apresentaram diferenças (p>0,05) em função dos níveis crescentes de algas. Conclusão: A inclusão de Chlorella spp. não modificou a fermentação in vitro ou a produção de CH4em dieta à base de silagem de milho.Antecedentes: Generalmente, los forrajes en los sistemas de producción de cría y levante de ganado tienen baja cantidad de proteína cruda y alta de fibra, limitando la productividad animal e incrementando la emisión de gases de efecto invernadero. Chlorella spp., una microalga verde, presenta características promisorias para proveer nutrientes, especialmente nitrógeno, en dietas bajas en proteína. Sin embargo, existe información limitada relacionada con la inclusión de Chlorella spp. sobre la fermentación y la producción de metano (CH4) in vitro de la dieta. Objetivo: Evaluar el efecto de incrementar la inclusión de alga (Chlorella spp.) sobre el perfil de fermentación in vitro y la producción de CH4 de una dieta basada en ensilaje de maíz. Métodos: Las incubaciones fueron realizadas en tres días diferentes usando ensilaje de maíz y residuo de algodón como sustrato (en relación 70:30, respectivamente). Los tratamientos fueron: un tratamiento control (sin alga), e inclusiones de 1, 5 y 10% de alga en el sustrato. El fluido ruminal fue colectado de dos novillos mestizos Angus con cánula ruminal, alimentados con una dieta de ensilaje de maíz y residuo de algodón a voluntad. El pH final, la concentración de ácidos grasos volátiles (VFA) y nitrógeno amoniacal (NH3-N), la digestibilidad in vitro de la materia orgánica (IVOMD), y la producción de gas total y CH4 fueron determinadas después de 24 h de fermentación. Las variables fueron evaluadas usando el procedimiento MIXED del software SAS y las medias fueron comparadas usando contrastes de polinomios ortogonales. Resultados: Niveles crecientes de alga incrementaron (p0,05) entre los niveles de alga. Además, las proporciones molares de VFA y la relación acetato:propionato no se afectaron con el incremento (p>0,05) en la concentración de alga. Finalmente, la producción de gas y de CH4 no fueron diferentes (p>0,05) entre tratamientos. Conclusión: La inclusión de Chlorella spp. no modifica la fermentación in vitro ni la producción de CH4 en una dieta basada en ensilaje de maíz
Effects of Processing Methods and Inclusion Levels of Dried Garlic on In Vitro Fermentation and Methane Production in a Corn Silage-Based Substrate
No full textGarlic (Allium sativum) contains secondary compounds that are known to modify rumen fermentation parameters and decrease methane (CH4) emissions. The objective was to evaluate the effects of increasing the inclusion levels and processing methods of garlic on in vitro fermentation and CH4 production. Treatments were arranged in a randomized complete block design with a 2 × 3 × 2 + 1 factorial arrangement, where the main factors were the initial condition of garlic (intact or smashed), drying process (freeze-dried, oven-dried, or autoclaved), and garlic proportion in the diet (2.5 and 5%) and one control (without garlic supplementation). Incubations were conducted using corn silage and cotton-gin trash (80:20, respectively) as basal substrates on three different days. Final pH, the concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH3-N), in vitro organic matter digestibility (IVOMD), total gas production, and CH4 concentration were determined after 24 h. Initial garlic condition or drying processing neither modify (p > 0.05) the in vitro fermentation nor the CH4 production. However, increasing garlic inclusion linearly increased (p < 0.05) IVOMD, the concentration of the total VFA, and the proportion of propionate. Also, the concentration of NH3-N and the proportion of acetate increased quadratically (p < 0.05) with greater garlic inclusions. Finally, garlic inclusion did not affect (p > 0.05) gas and CH4 production. In conclusion, increasing garlic levels, but not the processing methods, improved in vitro fermentation but did not modify CH4 emissions under in vitro conditions
Effect of Cashew Nutshell Extract, Saponins and Tannins Addition on Methane Emissions, Nutrient Digestibility and Feeding Behavior of Beef Steers Receiving a Backgrounding Diet
No full textThe beef industry contributes to greenhouse gas emissions through enteric methane emissions, exacerbating climate change. Anacardic acid in cashew nutshell extract (CNSE), saponins and tannins (ST) are plant secondary metabolites that show promise in methane mitigation via antimicrobial effects, potentially exerting changes in ruminal fermentation patterns. This study examined the impact of CNSE, ST, and their combination on methane emissions, digestibility, intake, and performance of sixteen Angus crossbred steers (347 ± 30 kg) receiving a backgrounding diet (70:30 corn silage: cottonseed burrs). The study used a 4 × 4 Latin square design (4 steers, 4 treatments, 4 periods) with a 2 × 2 factorial arrangement, including the main effects of additive (CNSE or ST) fed individually or combined. Thus, steers received the following treatments: (1) no additive, (2) CNSE only, (3) ST only, or (4) both (CNSEST). Non-supplemented steers registered eight more feedbunk visits/d than ST-steers and spent an extra 10 min/d on the feedbunk. The addition of ST tended to increase dry matter, organic matter, and neutral detergent fiber intake. Additives fed individually reduced CP digestibility. Intake of the carrier containing CNSE only was lesser and coincided with a greater methane yield in that treatment. Digestibility and methane mitigation were improved after CNSEST compared with individual inclusion, suggesting synergistic reactions enhanced methane mitigation effects in fibrous diets without affecting the digestibility of nutrients nor animal growth performance
Feeding rumen-protected choline during the periconceptional period programs postnatal phenotype of suckled beef calves
No full textAbstract Background Supplementation of choline chloride in culture medium programs the preimplantation bovine embryo to increase weaning weight of the resultant calf. Here, it was hypothesized that similar programming actions of choline can be induced by feeding rumen-protected choline (RPC) to beef cows during the periconceptional period. Results A preliminary experiment was conducted to determine changes in circulating concentrations of choline and its metabolites after RPC supplementation. Suckled beef cows were individually fed 0, 30, 60, and 90 g of RPC (i.e., 0, 8.6, 17.3 and 25.9 g choline chloride) and blood samples were collected at random times after feeding. There were no differences in plasma concentrations of choline or its metabolites between groups. In the second experiment, effects of feeding 60 g/d RPC from d −1 to 7 relative to timed artificial insemination were examined for suckled beef cows. Feeding RPC did not affect pregnancy or calving rates, pregnancy losses, plasma concentrations of pregnancy-associated glycoproteins, gestation length or calf birth weight. Calves from RPC fed dams were lighter than control calves at ~118 days of age (range 75–150; age included in the statistical model) and at weaning at ~248 days of age. There was no effect of treatment on hip height at ~118 days of age although there was a trend for RPC calves to be shorter at weaning. Weight/height ratio was lower for RPC than control at both 118 and 248 days of age. Treatment did not affect testis weight at ~118 days of age. Conclusions Supplementation of RPC during the periconceptional period programmed development to alter calf phenotype in the postnatal period. The net result, reduced body weight, was the opposite of the phenotype caused by the addition of choline to embryo culture medium
