The objective of this paperwas to study the effect of yield of Brachiaria humidicola cv Chetumal grass at different frequencies and intensities of grazing. The cutoff frequencies of 21 and 28 d and the intensities of 9-11 and 13-15 cm were evaluated, which were randomly distributed in a random block design with 2*2 factorial arrangement with three replicates. Management effects on dry matter accumulation were observed, with accumulation at lower frequency and light grazing intensity being greater. Forage production had a seasonal distribution of 66, 26 and 7% in the rainy season, north and dry seasons, respectively. The leaf ratio in harvested forage was 20, 30 and 86% for north, dry and rainy seasons, respectively. Reductions in dry matter digestibility were observed in the north and rainy seasons as the cut interval increased. The crude protein with severe grazing was 11, 10 and 17% higher in the north, dry and rainy times than with light. It is concluded that the highest forage production was obtained when harvesting at a light intensity of 13-15 cm, every 28 d and the highest protein content and digestibility was obtained when the forage was harvested at severe intensity every 21 d. El objetivo de la investigación fue estudiar el efecto del rendimiento del pasto Brachiaria humidicola cv Chetumal a diferentes frecuencias e intensidades de pastoreo. Se evaluaron las frecuencias de corte de 21 y 28 d y las intensidades de 9-11 y 13-15 cm, que se distribuyeron de forma aleatoria en un diseño de bloques al azar con arreglo factorial 2*2 con tres repeticiones. Se observaron efecto del manejo en la acumulación de materia seca, siendo mayor la acumulación a menor frecuencia e intensidad ligera de pastoreo. La producción del forraje tuvo una distribución estacional del 66, 26 y 7% en épocas de lluvias, nortes y seca, respectivamente. La proporción de hoja en el forraje cosechado fue de 20, 30 y 86% para las épocas de nortes, seca y lluvias, respectivamente. Se registraron reducciones en la digestibilidad de la materia seca en las épocas de nortes y lluvias al aumentar el intervalo de corte. La proteína cruda con pastoreo severo fue 11, 10 y 17% mayor en las épocas de nortes, seca y lluvias que con el ligero. Se concluye que la mayor producción del forraje se obtuvo al cosechar a una intensidad ligera de 13-15 cm, cada 28 d y el mayor contenido de proteína y digestibilidad se obtuvo cuando el forraje se cosecho a intensidad severa cada 21 d.

The objective of this research was to evaluate the productive capacity of orchard grass alone and associated with perennial ryegrass and white clover sown at different proportions. Treatments consisted of the following associations and monoculture: 100-00-00, 70-20-10, 50-00-50, 40-40-20, 40-20-40, 20-70-10, 20-40-40, and 00-50-50% of orchard grass, perennial ryegrass, and white clover, respectively. The eight treatments were randomly distributed into 24 experimental plots of 9 × 8 m according to a completely randomized block design with three replicates. On average, the associations that had the highest herbage yield in two years were 40-20-40, 20-70-10, and 20-40-40 with 21038, 20709, and 20073 kg DM ha⁻¹, respectively, and the lowest herbage yield was registered by monoculture with 12793 kg DM ha⁻¹. The associations with higher herbage yield exceeded that of monoculture by about 61%. Independently of the association, in summer, the highest percentage was found to be orchard grass and in winter, it was white clover, while perennial ryegrass had the lowest percentage throughout the study. The associations of grasses and legumes have higher herbage yield when compared with the monoculture of orchard grass. The legume has a better behaviour when it is associated with perennial ryegrass and worse with orchard grass.

The objective of this study was to evaluate the biomass production, chemical composition, proximate analysis, calorific value and theoretical yield of bioethanol of Taiwan grass under 6 cutting frequencies. The highest production of biomass (33 t DM/ha), cellulose content (41.3%), calorific value (17.5 MJ/kg DM) and potential bioethanol yield (7,936 L/ha) were recorded at a cutting frequency of 180 days. The highest moisture content of the dehydrated samples and ash and crude protein concentrations were observed at a harvest frequency of 30 days with 9.2, 12.1 and 10.5%, respectively. The highest concentrations of extractives were obtained at harvest frequencies of 60 and 120 days (13.9 and 13.7%, respectively), while lignin concentrations were greatest at harvest frequencies of 150 and 180 days (21.1 and 20.9%, respectively). The highest concentration of fixed carbon was observed at a harvest frequency of 90 days (18.5%), while the lowest concentration of volatile matter occurred at a harvest frequency of 30 days. The data indicate that Taiwan grass has significant potential for use to produce bioethanol but assessment of the carbon footprint, life cycle analysis, energy yield (energy produced:energy consumed) of the entire production process is needed to ensure there are positive effects on climate change and greenhouse gas emissions before this process is adopted.

El objetivo de este estudio fue evaluar el rendimiento, los perfiles nutrimental y de fermentación ruminal in vitro del pasto maralfalfa (Cenchrus purpureus Schumach.) Morrone, a cuatro frecuencias de corte. Los tratamientos se distribuyeron en bloques al azar en parcelas divididas con tres repeticiones. Los datos se analizaron en modelo lineal generalizado (GLM, por sus siglas en inglés) con el paquete estadístico de Statistical Analysis Software (SAS) y las medias se compararon con Tukey. El mayor rendimiento de biomasa (20.2 Mg MS ha-1), fibra detergente neutro (FDN) (66.7%), celulosa (CL) (45.4%), energía (16.3 MJ kg-1 MS) y dióxido de carbono (CO2) (89.7%) se obtuvo en la frecuencia de corte a cada 120 días (p < 0.05). El contenido de proteína cruda (PC) (9.3%), hemicelulosa (HC) (17.6%), cenizas (11.7%), humedad (8.4%) y lignina detergente ácido (LDA) (4.7%), ácido acético (77.8%), propiónico (29.4%), butírico (12.6%), CH4 (11.9%) y la Digestibilidad de la materia seca (DivMS) (55.6%), fue más elevado en la frecuencia de corte a 30 días (p < 0.05). El contenido de extracto etéreo (EE) (1.8%, p < 0.05) fue mayor en la frecuencia de corte al día 90. El pasto maralfalfa tiene una mejor composición química y mayor contenido de ácidos grasos volátiles (AGV) en etapas tempranas de corte.

Meat is a complex food with a structured nutritional composition that makes it an essential component of the human diet. In particular, the meat of native guajolote that is traditionally raised in natural conditions is an important dietary source of proteins of high biological value for the rural population of Mexico. The study aimed to evaluate fatty acids (FAs) profile and nutritional indices of breast and leg meat of native guajolote subjected to two heat treatments. For the study, a total of sixty muscle samples (30 breast meat and 30 leg meat) from adult male native guajolotes were used. The FA profile and nutritional indices were evaluated in raw meat (control) and meat subjected to two heat treatments (boiled and baked). The heat treatments, independently of the type of muscle, increased (p ≤ 0.05) the concentration of saturated (SFA) and monounsaturated FA (MUFA); in contrast, polyunsaturated FA (PUFA) decreased. Likewise, the dietary FA index, which has a negative hypercholesterolemic effect, and the atherogenic index increased in guajolote meat from the effect of the heat treatments, while the essential and undesirable hypercholesterolemic FA indices decreased. In conclusion, heat treatments increase the content of SFA and MUFAs in breast and leg meat of native guajolote. Boiling or baking the meat deteriorates PUFAs but increases the nutritional indices. The present investigation would provide valuable information for the guajolote meat product processing.

Urochloa grasses produce high biomass yields and their nutritional value is acceptable for ruminant feeding. The objective of this research was to evaluate the biomass of three Urochloa grasses (Cayman, Humidicola and Toledo) and to determine the best forage source based on their chemical composition and biomass yield under a warm subhumid climate. The work was carried out in 2020 in Isla, Veracruz, Mex. Annual biomass production and chemical composition were evaluated at four regrowth ages [RA; 30, 60, 90, and 120 d after regrowth (DAR)]. A completely randomized block experimental design with a split-plot arrangement was used, where: the large plot was the genotype and the small plot was the regrowth age (30, 60, 90, and 120) with three repetitions. The data were analyzed by analysis of variance (ANOVA) using the GLM/SAS procedure and the treatment means were compared with the Tukey test (ɑ=0.05). The biomass, hemicelluloses, lignin, and ash content was higher (p ≤ 0.05) at 120 DDR, being 19.5 t ha-1 year-1; 21.2, 7.0 and 12.2%, for Humidicola grass, respectively, while cellulose was higher in Toledo grass 41.1 %. Crude protein and acid detergent fiber (p ≤ 0.05) were higher than 30 DDR, 10% and 42.4% for Cayman and Humidicola, respectively. Humidicola, at 90 DDR, presented the highest value of neutral detergent fiber (66.2%, p ≤ 0.05), while the ether extract was not different between cultivars (p ≥ 0.05). According to biomass yield and chemical composition, Humidicola grass is a high-quality forage for ruminants in tropical conditions.