Plant Biomass and Bovine Live Weight Changes in Mono-Specific and Mixed Pastures during the Rainy Season in Dry Tropical Mexico

Dry tropics suffer long drought periods each year, negatively affecting the amount and digestibility of forage for cattle production. The aim of this study was evaluate different pasture types, grazed by cattle during the rainy season. Three hectares were prepared to compare: grass monoculture, Andropogon gayanus (G); a grass-legume mixture of A. gayanus and Clitoria ternatea (GL), and a grass-legume-tree mixture of A. gayanus, C. ternatea and Morus alba (GLT). Two grazing cycles (4 d grazing followed by 32 d resting; 72 d total) were completed. Three heifers (average initial weight 192 kg) grazed each experimental unit. The amounts of forage offered, remaining after grazing, and removed by animals differed significantly among the pasture treatments. Total forage offered by period was 2007, 4089, and 4192 DM kg/ha for G, GL, and GLT, respectively. Total residual forage was 1074, 1878 and 2613 DM kg/ha respectively, while total forage removed was 934, 2209, and 1579 DM kg/ha, respectively. Differences for offered forage were detected only for residual and consumed forage for GL prairies. Differences in available forage were mainly due to differences in the amount of stem and live material. Daily weight gain was 0.138, 0.504 and 0.501 kg per animal for G, GL, and GLT, respectively. Mixed pasture treatments yielded better live weight gain due to the better quality of available forage

Selenium affects genes associated with immunity and apoptosis in in vitro follicles of ewes

Selenium plays an important role in bodily functions. It activates immune cells such as neutrophils and immunity through T cells. However, its role in ovarian follicular gene expression has not been reported. The effects of selenomethionine (SeMet) on gene expression in in vitro ewe follicles and their relationship with immunity and apoptosis were studied. Preovulatory follicles were randomly cultured, and SeMet was added to the culture, followed by incubation for 24 h. Total RNA was extracted from follicles and placed on a microarray chip. Gene expression was analyzed using GenArise and classified using the DAVID v6.8 bioinformatics program based on the Gene Ontology and Kyoto Encyclopedia for Genes and Genomes (KEGG). Gene pathways were designed using Cytoscape v3.7.2. There were 2,538 differentially expressed genes (DEGs): 1,228 upregulated and 1,310 downregulated. The upregulated genes were classified into 32, 18, and 12 nodes related to biological processes, cellular components, and molecular functions, respectively. KEGG assigned these genes to 41 metabolic and signaling pathways. 94 genes were involved in eight pathways associated with immune processes. The expression levels of CD8, NFAT2, and CD48 were quantified using RT-qPCR. Selenium activated gene expression in the in vitro preovulatory follicles of ewes, some of which were related to the immune system. The relationship among CD8, NFAT2, and CD48 genes suggests a possible immune pathway related to follicular apoptosis regulation

Forage Biomass and Bovine Live Weight Changes within Monospecific and Mixed Prairies over the Dry Season in Tropical México

In the tropical systems of cattle grazing, the limited period of forage production and low forage protein content and digestibility of the same, are the main constraints to increasing live weight gain. Grass-legume pasture improves forage quantity and quality and sowing mixed swards in both the wet and dry tropics is now common practice. However, much less is known if inclusion of a fodder tree as a third component could further improve forage parameters. The aim of this study was to evaluate three types of grasslands, grazed by cattle in the dry season of the dry tropics. Swards were established to compare: grass only (PP), grass-legume (PA) and silvo-pastoral (PSP) pastures on basis of forage on-offer, residual and disappeared and bullock’s daily live-weight gain. Species used were: Andropogon gayanus Kunth, Clitoria ternatea Linn and Morus alba Linn

Rendimiento de semilla e índice de llenado de grano en diversos ecotipos de tres especies del género Brachiaria

The aim of this study was to characterize variability in seed production and quality of three species of the genus Brachiaria, at Isla, Veracruz, México. Twelve Brachiaria brizantha (Trin.) Griseb, nine B. decumbens Stapf. and six B. humidicola (Rendle) Schweick ecotypes were studied. Plots were fertilized with 100 kg ha-1 of N and 50 kg ha-1 of P2O5, in the rainy season. Reproductive tiller density (RTD), crude (CSP) and classified seed yield (CLSY) and seed dormancy were measured. Filling grain index (FGI) and productive efficiency were used as yield indicators. Ecotypes were allocated in a completely randomized block design. Classified seed production of 16549 and 6387 B. brizantha ecotypes was 139 and 151 kg ha-1, respectively. In B. decumbens and B. humidicola the ecotypes 16497 and 6133 with 262 and 345 kg ha-1 of CLSP were the most productive. Commercial controls Insurgente, Chontalpo and Chetumal produced 32, 106 and 21 kg ha-1 of CLSY, respectively. These yields represented 21, 40 and 6 % of CLSY of the best ecotypes within each specie. There was not a direct relationship between CLSY and RTD, hence both are independent characters, which makes FGI a variable attribute in this genus. Seed dormancy did not show significant differences (P>0.05). Reproductive tiller density management in Brachiaria ecotypes with higher FGI, and the use of available genetic diversity are an alternative to increase the classified seed yield.Para caracterizar la variabilidad en rendimiento y calidad de semilla de varios ecotipos de tres especies del género Brachiaria, se realizó esta investigación, en condiciones de temporal, en Isla, Ver., México. Se evaluaron 12 ecotipos de B. brizantha (Trin.) Griseb, 9 de B. decumbens Stapf. y 6 de B. humidicola (Rendle) Schweick, fertilizados con 100 y 50 kg ha-1 de N y P2O5, respectivamente. Se midió la densidad de tallos florales, el rendimiento de semilla cruda, y clasificada (RSCLA), así como el rompimiento de latencia. Se analizaron índices de llenado de semilla y eficiencia productiva como indicadores de rendimiento. Los ecotipos se distribuyeron en un diseño en bloques al azar. El RSCLA en B. brizantha fue mayor (P0.05) en el rompimiento de latencia. El manejo de la DTF, en ecotipos de Brachiaria con mayor eficiencia de llenado, y la disponibilidad de recursos genéticos, son una alternativa para incrementar el redimiento de semilla cruda dosificada

Producción de carne en praderas de estrella de áfrica fertilizadas y con suplementación al ganado

Se realizó un estudio para determinar la producción de carne en praderas de zacate Estrella de África (Cynodon plectostachyus) fertilizadas con distintas cantidades de nitrógeno y un nivel fijo de fósforo

Nutritional Sensitivity Per Morphological Component in \u3ci\u3eUrochloa\u3c/i\u3e Hybrid under Tropical Environments

Camello® (GP 3025) is a tolerant to drought Urochloa hybrid grass showing good forage production, early flowering with high regrowth rates. The objective was to define nutrient concentration changes by morphological component and, their differences for two tropical contrasting environments. Nutrient concentrations differences (P≤0.05) were observed among morphological components over time. In environments (Aw1) the morphological components showed higher average protein content in comparison to that from hostile conditions (Aw0); lamina (12.2% vs 10.4%), pseudostem (9.5% vs 6.6%) and sheath (9.8% vs 6.8%). Hostile environments (Aw0) promoted increases for FAD (47.9%, 46.9%, pseudostem and sheath, respectively) and lignin (6.6%, 9.1% pseudostem and sheath, respectively). The nutritional changes per morphological components is the best tool to define optimal moment for harvesting on nutritional bioavailability for livestock production intensification

Diversidad forrajera del pasto banderita [Bouteloua curtipendula (Michx.) Torr.], en poblaciones de zonas áridas y semiáridas de México

The objectives of the present study were to evaluate sideoats grama [Bouteloua curtipendula (Michx.) Torr.] populations, to set an ex situ plot, and to asses morphological diversity. From 2000 to 2003, 577 sideoats grama populations were collected in 13 Mexican States. In 177 established ecotypes, the following plant morphologic attributes were assessed: vigour, regrowth, forage texture, dry matter production potential, phenology, seed production potential, leaf density, tiller type and leaf:stem ratio. Variables were analysed through principal component analysis (PCA) using the PRINCOMP procedure. The first three components explained 62.9 % of the total observed variation. Principal component one (PC1) included characteristics related with growth and explained 36.4 % of variation, vigour, leaf density, and leaf:stem ratio were the most important variables. The PC2 included characteristics related with propagation and explained 15.1 % of variation, seed potential and tiller type were important variables. The PC3 explained 11.4 % of variation, forage texture and phenology were the most important variables. The PC1 and PC2 revealed the existence of six different groups. This dispersion reflects a wide morphological and genetic variation in this species, it was observed that this dispersion is not systematic, since it is possible to establish groups based on physiographic adaptation of ecotypes instead of locality or place of origin. It can be concluded that this variation is important while selecting the best forage characteristics in order to set up a genetic improvement program.El objetivo fue comparar poblaciones de banderita [Bouteloua curtipendula (Michx.) Torr.], establecer una colecta ex situ y cuantificar la diversidad morfológica. Durante los años 2000 al 2003, se recolectaron 577 ecotipos de poblaciones distribuidas en 13 estados de México. Con 177 ecotipos sobresalientes se evaluó: capacidad de rebrote, textura de hojas, establecimiento, fenología, potencial de semilla, densidad de hoja, vigor de planta, tipo de macollo y relación hoja-tallo. Se aplicó un análisis de componentes principales (ACP) con el procedimiento PRINCOMP. Los tres primeros componentes explicaron 62.9 % de la variación total observada. El CP1 incluyó características relacionadas con crecimiento y explicó 36.4 % de la variación, donde vigor, densidad de hojas y relación hoja:tallo fueron las variables importantes. El CP2 incluyó características relacionadas con variables de propagación y dispersión y explicó 15.1 % de la variación, donde potencial de producción semilla y tipo de macollo fueron las variables importantes. El CP3 explicó 11.4 % de la variabilidad, donde textura de hoja y fenología fueron las variables importantes. El CP1 y CP2 revelaron la existencia de seis grupos diferentes. Esta dispersión, refleja la amplitud de la variación morfológica y, muy probablemente genética en esta especie, se observó que esta dispersión no es aleatoria, ya que es posible establecer grupos con base en sus áreas de adaptación climática, más que por localidades u origen. Esta variación pone de manifiesto la importancia de evaluar la riqueza natural para un programa de mejoramiento genético

Caracterización morfológica y molecular de poblaciones de pasto banderi

Sideoats grama [Bouteloua curtipendula (Michx.) Torr.] is an important native species for cattle production. However, inappropriate grazing practices have reduced its genetic diversity. The morphological and genetic diversity of 51 populations of sideoats grama in Chihuahua State was explored and analyzed. Transplanting was performed under natural conditions; two years later, morphological characterization was performed. To assess genetic variability AFLP molecular markers were used. Principal component analysis (PCA) showed that the first three components (PC) explained 73.83 % of variation. PC1 showed a significant correlation (P<0.0001) in dry matter yield (88 %), stem density (85 %), tiller diameter (83 %), height of foliage (82 %), plant height (79 %), and leaf length (65 %). An AFLP analysis with four pairs of primers detected 186 bands; 80.67 % (150 bands) had polymorphism. The highest percentage of polymorphism (93.75 %) and polymorphic bands (48) was obtained with the primer combination of EcoRI-ACT + MseI-CTG. Sideoats grama population presented a high morphological and molecular variability. Based on high forage potential, ecotypes (444, 359 y 557) were selected to be included in grassland restoration programs.El pasto banderita [Bouteloua curtipendula (Michx.) Torr.] es una especie nativa de importancia ganadera; sin embargo, prácticas inadecuadas de pastoreo han reducido su diversidad genética. Se exploró y analizó la diversidad morfológica y genética de 51 poblaciones de pasto banderita del estado de Chihuahua. Las plantas se trasplantaron bajo condiciones de temporal. Dos años después se realizó la caracterización morfológica. Para evaluar la variabilidad genética se utilizaron marcadores moleculares AFLP. El análisis de componentes principales (ACP) mostró que los tres primeros componentes (CP), explican el 73.83 % de la variación. El CP1 presentó una correlación significativa (P<0.0001) con rendimiento de materia seca (88 %), densidad de tallos (85 %), diámetro de macollo (83 %), altura de follaje (82 %), altura de planta (79 %) y longitud de hoja (65 %). El análisis de AFLP con cuatro pares de iniciadores detectó 186 bandas; 80.67 % (150 bandas) presentó polimorfismo. El mayor porcentaje de polimorfismo (93.75 %) y bandas polimórficas (48) se obtuvo con la combinación de iniciadores EcoRI-ACT+MseI-CTG. Las poblaciones de banderita presentaron alta variabilidad morfológica y molecular. Se detectaron ecotipos (444, 359 y 557) con potencial forrajero de acuerdo a su variabilidad morfológica y molecular para ser incluidos en programas de restauración de pastizale

Effect of Grazing Management on Herbage Accumulation of Lucerne-Orchard Grass Sward

Throughout most of México, lucerne (Medicago sativa) is the primary forage legume used in the dairy industry. Unfortunately, lucerne does not grow in late autumn and winter due to adverse weather. Recent studies with lucerne have suggested that the inclusion of a companion grass will invariably increase the seasonal distribution and total annual yield of swards (Laidlaw & Teuber, 2001). However the management of mixed swards containing lucerne is difficult as a grazing frequency or intensity which suits one species may be detrimental to the other. Changes in balance between grass and legume, especially in grazed swards, have been observed. In México mixtures of lucerne-orchard grass have a good persistence and productivity. However the explanation for this is unclear. This study examined the effects of different grazing management practices on lucerne-orchard grass production and seasonal distribution

Evaluación de la distancia entre plantas sobre el rendimiento y calidad de semilla de Brachiaria brizantha

The objective was evaluating the effect of plant spacing on seed yield and quality in Bracchiaria brizantha cv. Marandú. The experiment was carried out in rain fed conditions in 2007 at the Universidad de Papaloapan, Loma Bonita, Oaxaca, Mexico. Six plant distances (broadcast, 25*25 cm, 50*50 cm, 75*75 cm, 100*100 cm and 125*125 cm between rows and plants, respectively) were assessed. To that end, a completely randomized block design with four replicates was set. The following variables were analyzed: pure seed yield (PSY), pure germinable seed yield (GPSY), number of panicles per m-2, panicle length,seed harvested per panicle, 1,000 seed weight, spikelet abscission rate, seed purity and germination. PSY and GPSY showed differences among treatments (PEl objetivo fue evaluar el efecto de la distancia entre plantas en el rendimiento y calidad de semilla de Brachiaria brizantha cv. Marandu. El experimento se realizó en temporal durante 2007, en la Universidad del Papaloapan, Loma Bonita, Oaxaca. Se evaluaron seis distancias entre plantas (voleo, 25 x 25, 50 x 50, 75 x 75, 100 x 100 y 125 x 125 cm entre líneas y plantas, respectivamente), con un diseño de bloques completos al azar, con cuatro repeticiones. Se midió el rendimiento de semilla pura (RSP), rendimiento de semilla pura germinable (RSPG), número de panículas m-2, longitud de panícula, número de semillas cosechadas por panícula, peso de 1,000 semillas, porcentaje de dehiscencia, semilla pura y germinación. El RSP y RSPG varió entre tratamientos (P0.05). Se concluye que el mayor rendimiento de semilla de B. brizantha cv. Marandu, se logró con la distancia 25 x 25 cm entre líneas y plantas, respectivamente. La germinación de la semilla no fue mejorada por ninguno de los tratamientos evaluados