Análisis de crecimiento estacional de una pradera de trébol blanco (Trifolium repens L)

The objective of the present study was to assess a growth analysis of white clover (Trifolium repens L.) and determine the optimal harvest time per season. The experiment was carried out at the Colegio de Postgraduados, Campus Montecillo, Texcoco, Mexico. Twenty-four 3.7 X 1.7 m plots were used, distributed in a completely randomized design, with eight treatments and three replicates per station. The treatments consisted of successive weekly cuts, during a regrowth cycle of 8 wk, in each season of the year. At the beginning of the study, a uniform cut was made and the residual forage was determined. The evaluated variables were: accumulation of dry matter, botanical and morphological composition, and leaf area index of white clover. The highest forage accumulation (P<0.05) occurred in the eighth week in spring (2,688 kg DM ha-1). Leaf production was higher (P<0.05) in spring, autumn and winter. The highest leaf area index was reached in the eighth week in spring (3.0; P<0.05). It is recommend exploiting the white clover meadow in the sixth week of the spring-summer period and in the seventh week of autumn-winter.El objetivo del presente estudio fue evaluar un análisis de crecimiento del trébol blanco (Trifolium repens L) y determinar el momento óptimo de cosecha por estación. El experimento se realizó en el Colegio de Postgraduados, Campus Montecillo, Texcoco, México. Se utilizaron 24 parcelas de 3.7 X 1.7 m, distribuidas en un diseño completamente al azar, con ocho tratamientos y tres repeticiones por estación. Los tratamientos consistieron en cortes semanales sucesivos, durante un ciclo de rebrote de ocho semanas, en cada estación del año. Al inicio del estudio se realizó un corte de uniformización y se determinó el forraje residual. Las variables evaluadas fueron: acumulación de materia seca, composición botánica y morfológica e índice de área foliar del trébol blanco. La mayor acumulación de forraje (P<0.05) se presentó en la octava semana en primavera (2,688 kg MS ha-1). La producción de hoja fue mayor (p < 0.05) en primavera, otoño e invierno. El mayor índice de área foliar se alcanzó en la octava semana en primavera (3.0; P< 0.05). Se recomienda aprovechar la pradera de trébol blanco en la sexta semana para primavera-verano y séptima semana en otoño e invierno

Fertility in Cebú × brown Swiss cows treated with prostaglandins, progesterone and eCG

Objective: To evaluate the application of 1 or 2 doses of prostaglandin F2? (PGF2?), the use of progestogen on different days of the estrous cycle, and the use of eCG in estrus and fertility synchronization of Zebu × Brown Swiss cows. Design / Methodology / Approach: The study was based on three protocols. Protocol 1 consisted of two treatments: PGI) 26 cows were injected with a single dose of 25 mg PGF2?, and 10 cows with two doses of 25 mg PGF2? with a 14 day interval. Protocol 2 consisted of two treatments: NG14) 11 cows were implanted with 3 mg Norgestomet on day 7 of the estrous cycle, and NG7) 11 animals received the same dose on day 14. In protocol 3, all the cows were implanted with 3 mg Norgestomet for 9 days, 48 h before removing the implant, 25 mg PGF2? was applied. Once the implant was removed, the cows were distributed into two treatments. Norgestomet (n=11) without eCG and Norgestomet + eCG (500 IU) (n=11). &nbsp;&nbsp; Results: The application of PGF2? on two occasions had no influence (p&gt; 0.05) on the percentages of estrus or pregnancies. NG7 achieved estrus synchronization in 81.8% of the cows between 24 and 36 h, compared with 45.4% of NG14; however, the pregnancy rate was lower (p&lt;0.05). The application of eCG synchronized 90.9% estrus between 24 and 36 h, compared with 36.4% in the group where no eCG was applied. Study limitations / implications: The use of transrectal ultrasound is required to evaluate the ovarian structures present at the time of initiating an estrus synchronization protocol. Findings / conclusions: Cows that present corpus luteum do not require more than one injection of PGF2?, the percentage of pregnancy increases when Norgestomet is implanted on day 14 of the estrous cycle, in addition the application of eCG increases the percentage of synchronization of heat of the 24 to 36 h after withdrawal of progestogenObjective: To evaluate the application of one or two doses of prostaglandin F2?(PGF2?), the application of a progestogen on different days of the estrous cycle and theusage of eCG in the estrus synchronization and fertility of Zebu × Brown Swiss cows.Design / methodology / approach: The study was based on three protocols. The firstconsisted of two treatments: PGI) 26 cows were injected with a single 25 mg dose ofPGF2? and 10 cows with two 25 mg doses of PGF2? at a 14-day interval. Protocol 2consisted of two treatments: NG14) 11 cows were implanted with 3 mg of Norgestometon day 7 of their estrous cycle and NG7) 11 animals received the same dose on day 14.In protocol 3 all cows were implanted with 3 mg of Norgestomet for 9 days, 48 h beforeremoving the implant, 25 mg of PGF2? was applied. Once the implants were removed,they were distributed into two treatments. Norgestomet (n = 11) without eCG andNorgestomet + eCG (500 IU) (n = 11). Results: The application of PGF2? at two times had no influence (p &amp;gt; 0.05) in theestrous percentages and conception. The NG7 achieved estrous synchronization in 81.8% of the cows, in between 24 and 36 h, compared to 45.4 % of the NG14; however, theconception rate was lower (p ? 0.05). The eCG application synchronized 90.9 % ofestrous between 24 and 36 h, compared with 36.4 % of the group with no eCGapplication.Study limitations / implications: Transrectal ultrasounds are required to assess theovarian structures present at the time of the estrus onset in a synchronization protocol.Findings / conclusions: Cows that present corpus luteum do not require more thanone injection of PGF2?, the pregnancy percentage increases when Norgestomet isimplanted on day 14 of the estrous cycle, in addition the application of eCG increasesthe synchronization percentage of the heat between 24 to 36 h after the progestogenwithdrawal

El efecto del pastoreo mixto y de mono-especie en dos tipos de pradera sobre la calidad, desarrollo y rendimiento de forraje.

Se evaluó el impacto del pastoreo mixto vaca-oveja y de mono-especie (vaca) en dos tipos de pradera; alfalfa- ovillo (Medicago sativa-Dactylis glomerata) y otro con avena-ballico anual (Avena sativa-Lolium multiflorum), usando vacas Holstein y ovejas Criollas, sobre la calidad, desarrollo y rendimiento de forraje. El estudio, fue desarrollado bajo un diseño completamente al azar con dos repeticiones. El tipo de pastoreo no influyó (p>0.05) en cantidad, composición botánica y altura del forraje ofrecido. La dieta de vacas en pastoreo mixto sobre alfalfa- ovillo mostró cuatro veces más (p<0.05) material muerto que la de mono-especie. Las ovejas consumieron más (p<0.05) hojas de alfalfa y ballico anual que las vacas acompañantes. Solamente en alfalfa-ovillo las vacas en pastoreo mono-especie pastorearon 55% más tiempo (p<0.05) que las del mixto. El pastoreo mixto vacas-ovejas en praderas de dos especies de forrajes, permite mayor carga animal, sin dañar el rebrote y mayor eficiencia de cosecha forraje que el mono-especie. DOI: https://doi.org/10.54167/tecnociencia.v14i1.62

Análisis de crecimiento del pasto Cuba OM-22 (Pennisetum purpureum x Pennisetum glaucum) en el trópico seco

Objective: To analyze a growth curve of the Cuba OM-22 grass (Pennisetum purpureum x Pennisetum glaucum), to find the optimum harvest time, in the dry tropics. Design/methodology/approach: The variables were total yield and by leaf and stem component, height of the plant, intercepted radiation, growth rate, weight per stem, leaf: stem ratio and stem population. They were evaluated at 20 day intervals, over a period of 110 days, with the exception of the first sample that was at 30 days. The data were analyzed using the SAS GLM procedure, under an experimental randomized block design, with measures repeated over time, with three repetitions. Results: The maximum production of total yield and growth rate was reached at 110 days after cutting with 38,600 kg DM ha-1 and 435 kg DM ha-1 d-1, respectively. Limitations on study/implications: After 70 days, a greater biomass accumulation of biomass is reported, but with a lower quality of structural characteristics.&nbsp; Findings/conclusions: The optimal cutting moment of the Cuba OM-22 grass is when it has higher leaf yield in this growth analysis was at 70 days after cutting, reporting a height of 132 cm and intercepted radiation of 95%.Objetivo: El objetivo de este ensayo fue analizar una curva de crecimiento del pasto Cuba OM-22 (Pennisetum purpureum x Pennisetum glaucum), para encontrar el momento óptimo de cosecha, en el trópico seco. Diseño/Metodología/Aproximación: Las variables fueron rendimiento total y por componente hoja y tallo, altura de la planta, radiación interceptada, tasa de crecimiento, peso por tallo, relación hoja:tallo y población de tallos. Se evaluaron a intervalos de 20 días, en un periodo de 110 días, a excepción del primer muestreo que fue a los 30 días. Los datos se analizaron mediante el procedimiento GLM de SAS, bajo un diseño experimental de bloques al azar, con medidas repetidas en el tiempo, con tres repeticiones. Resultados: La máxima producción de rendimiento total y tasa de crecimiento se alcanzó a los 110 días después del corte con 38,600 kg MS ha-1 y 435 kg MS ha-1 d-1, respectivamente. Limitaciones del estudio/implicaciones: Después de los 70 días se reporta mayor acumulación de biomasa, pero con menor calidad de características estructurales.&nbsp; Hallazgos/conclusiones: El momento óptimo del corte del pasto Cuba OM-22 es cuando tiene mayor rendimiento de hoja en este análisis de crecimiento fue a los 70 días después del corte reportando una altura de 132 cm y radiación interceptada de 95%

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

Desempeño y estrategia de pastoreo de ovinos pelibuey alimentados con diferentes niveles de proteína: Estrategia de pastoreo de ovinos pelibuey

With the objective of evaluating the performance of Pelibueylambs fed with different levels of protein and Tanzania grass at two rotational grazingregimes. It was used completely random design. Were used 30 ewes of the Pelibueybreed with an initial live weight of 20.33±1.56 kg, which were distributed in 30pens of 2.5 m long x 0.80 m wide and in a 1.5 ha pasture divided into 0.25 ha. Theanimals were fed at 07:00 am and at 16:00 pm. With diets containing 10, 12, 14,16% CP and a control feed, the lambs were grouped and grazed in pastures at twointensities of 9-11 cm and 13-15 cm of residual height. Were evaluated dry matter(DM), growth rate (TC), bromatological analysis of the pasture and weight gain. Thehighest accumulation of MS and TC were obtained in the months of June and July.The residual height of 9-11 cm presented the highest content of crude protein (CP)and neutral detergent fiber (NDF). The highest values in weight gain were obtainedin lambs that grazed in pastures at a residual height of 9-13 cm and that weresupplemented with food with 14 and 16% CP. The Tanzania grass presented goodDM production and morphological components at an intensity of 13-15 cm. Whilethe lambs that were fed 16% CP in the ration presented the highest daily weightgains.Con el objetivo de evaluar el desempeño de corderas Pelibuey alimentadas con diferentes niveles de proteína y pasto Tanzania a dos régimen de pastoreo rotacional. Se utilizó un diseño completamente al azar. Se utilizaron 30 corderas de la raza Pelibuey con peso vivo inicial de 20.33 ±1.56 kg, que se distribuyeron en 30 corrales de 2.5 m de largo x .80 m de ancho y en una pradera de 1.5 ha divididas en 0.25 ha. Los animales se alimentaron a las 07:00 am y a las 16:00 pm. Con dietas que contenían 10, 12, 14, 16 %PC y un alimento testigo, las corderas se agruparon y pastorearon en praderas a dos intensidades de 9-11 cm y 13- 15 cm de altura residual. Se avaluaron materia seca (MS), tasa de crecimiento (TC), análisis bromatológico del pasto y ganancia de peso. La mayor acumulación de MS y TC se obtuvieron en los meses de junio y julio. La altura residual de 9-11 cm presentó el mayor contenido de proteína cruda (PC) y fibra detergente neutro (FDN).&nbsp; Los valores mayores en la ganancia de peso se obtuvieron en corderas que pastaron en praderas a una altura residual de 9-13 cm y que se suplementaron con alimento con 14 y 16% de PC. El pasto Tanzania presentó buena producción de MS y componentes morfológicos a una intensidad de 13-15 cm. En tanto que las corderas que se alimentaron con 16% PC en la ración presentaron las mayores ganancia diaria de peso

Caracterización del pasto mombaza como materia prima para producir bioetanol

The objective of this study, made in 2017, was to characterize mombaza grass (Megathyrsus maximus) to assess its potential as a raw material for the production of liquid biofuel (bioethanol). Annual biomass production, calorific power, chemical composition and theoretical bioethanol yield were determined at four cutting frequencies (30, 60, 90 and 120 d after regrowth). The data were analyzed with the GLM (SAS) procedure and the means of the treatments were compared with the Tukey test (p 0.05). The highest biomass production, calorific power, energy production, bioethanol production, FDN, LDA and hemicellulose were obtained at the cutting frequency of 120 d with 11 Mg ha-1 year-1; 16.1 MJ kg-1; 178.4 GJ ha-1 year-1; 238.2 L Mg-1 MS and 68.6, 6.5, 23.3%, respectively. However, the highest cellulose and FDA content were found at the cutting frequency of 90 d, with 41.2 and 47.4%, respectively. The highest values of humidity, PC and ash were found at the cutting frequency of 30 d with values of 8.2, 10.4 and 12.1%, respectively, while the EE content was higher at the cutting frequency of 60 d (1.6%). According to the results obtained in this study mombaza grass (Megathyrsus maximus) can be considered as an attractive raw material for the production of bioethanol in tropical climates.El objetivo de este estudio realizado en 2017 fue caracterizar el pasto mombaza (Megathyrsus maximus) para evaluar su potencial como materia prima para la producción de biocombustible líquido (bioetanol). La producción anual de biomasa, el poder calorífico, la composición química y el rendimiento teórico de bioetanol fueron determinadas en cuatro frecuencias de corte (30, 60, 90 y 120 d después del rebrote). Los datos se analizaron con el procedimiento GLM (SAS) y las medias de los tratamientos se compararon con la prueba de Tukey (p 0.05). La mayor producción de biomasa, poder calorífico, producción de energía, producción de bioetanol, FDN, LDA y hemicelulosa se obtuvieron en la frecuencia de corte de 120 d con 11 Mg ha-1 año-1; 16.1 MJ kg-1; 178.4 GJ ha-1 año-1; 238.2 L Mg-1 MS y 68.6, 6.5, 23.3%, respectivamente. No obstante, el mayor contenido de celulosa y FDA se encontraron en la frecuencia de corte de 90 d, con 41.2 y 47.4%, respectivamente. Los valores más altos de humedad, PC y cenizas se encontraron en la frecuencia de corte de 30 d con valores de 8.2, 10.4 y 12.1%, respectivamente, mientras que el contenido de EE fue mayor en la frecuencia de corte de 60 d (1.6%). De acuerdo con los resultados obtenidos en este estudio el pasto mombaza (Megathyrsus maximus) puede ser considerado como una materia prima atractiva para la producción de bioetanol en climas tropicales

Acumulación de forraje, composición morfológica e intercepción luminosa en Triticale 118 (X Triticosecale Wittmack)

Con el objetivo de obtener la curva de acumulación de forraje, componentes morfológicos e intercepción luminosa para determinar el momento óptimo de corte, en forraje de Triciale 118. El estudio se realizó en Texcoco, Estado de México, bajo un sistema de riego, durante el invierno del año 2012-2013(ciclo 1) y 2013-2014 (ciclo 2). La cosecha se realizó cada siete días, iniciando a los 43 días después de la siembra (dds) y hasta que la acumulación de forraje disminuyó. En cada cosecha se registró la altura promedio de 20 plantas, la radiación interceptada (RI), la acumulación de materia seca, la composición morfológica e índice de área foliar (IAF). En el ciclo 1 la máxima acumulación de forraje se obtuvo a los 84 dds con un rendimiento de 1 852 kg de MS ha-1, en la etapa de espigamiento, se obtuvo una RI de 75% y una altura de planta de 52 cm, pero por una helada no se hicieron los muestreos. En el caso del ciclo dos la máxima acumulación de forraje ocurrió a los 119 dds con un valor de 8 733 kg de MS ha-1, donde el momento óptimo de corte fue entre los 77 y 91 dds, cuando la planta alcanzo una RI de entre 85 y 86%, IAF entre 2.3 y 3.2, respectivamente y un promedio de 58 cm. En este experimento se estableció con la RI, IAF y altura se puede definir el momento óptimo de cosecha del Triticale 118, obteniendo forraje de calidad.The objectives were to obtain the forage accumulation curve, morphological components and light interception to determine the optimal cutting time for green forage of Triticale 118. The study was carried out in Texcoco, State of Mexico, under an irrigationsystem, during the winter of the year 2012-2013 (cycle 1) and 2013-2014 (cycle 2). The harvest was carried out every seven days, starting at 43 days after sowing (dds) and until the forage accumulation decreased. The average height of 20 plants, intercepted radiation (IR), dry matter accumulation, morphological composition and leaf area index (LAI) were recorded in each harvest. In cycle 1 the maximum forage accumulation was obtained at 84 ddswith a yield of 1852 kg of DM ha-1, in the gleaning stage, an IR of 75% and a plant height of 52 cm were obtained, but due to a frost, it was not possible to continue sampling. In the case of cycle 2, the maximum forage accumulation occurred at 119 ddswith a value of 8 733 kg of DM ha-1, where the optimal cutting moment was between 77 and 91 dds, when the plant reached an IR of between 85 and 86%, LAI between 2.3 and 3.2, respectively, and an average of 58 cm. In this experiment, it was established that, with the IR, LAIand height, the optimum harvest time for Triticale 118 can be defined, obtaining quality forag

Dinámica poblacional de tallos de ovillo (Dactylis glomerata L.) solo y asociado con ballico perenne (Lolium perenne L.) y trébol blanco (Trifolium repens L.)

The objective of this research was to evaluate tiller population of orchard grass seeded with perennial ryegrass and white clover in different proportions and single. Treatments consisted of the associations: 20-70-10, 70-20-10, 100-00-00, 40-40-20 % of orchard grass (OG), perennial ryegrass (RG) and white clover (WT) respectively. Treatments were distributed in a randomized complete block with three replications. The association 70-20-10 of OG-RG-WT had greatest tiller density of OG with an average of 3,750 tiller m-2, and the lowest in 100-00-00 with an average of 2,400 tiller m-2 (P<0.05). There were few tiller in perennial ryegrass in all associations, with an average of 225 tiller m-2. Two highest peaks in the tiller population in OG and RG were found in autumn and winter. Regardless of the association, in the spring season more weight per tiller was found with 0.30 and 0.42 g tiller-1, OG and RG and less in winter with 0.13 and 0.14 g tiller-1, OG and RG, respectively. In conclusion, all associations in population dynamics of OG tiller tended to be maintained; in contrast, on single OG and RG tended to decrease.El objetivo de esta investigación fue evaluar la densidad de tallos del pasto ovillo en monocultivo, y asociado con ballico perenne y trébol blanco  en diferentes proporciones. Los tratamientos consistieron de las siguientes asociaciones: 20-70-10, 70-20-10, 100-00-00, 40-40-20 % de pasto ovillo (Ov), ballico perenne (Ba) y trébol blanco (Tr), respectivamente. Los tratamientos se distribuyeron en un arreglo de bloques al azar con tres repeticiones. La asociación 70-20-10 de Ov-Ba-Tr es la que presenta mayor densidad de tallos de Ov, con un promedio de 3,750 tallos m-2, y la menor densidad de tallos fue en el Ov en monocultivo (100-00-00), con un promedio de 2,400 tallos m-2 (P<0.05). La población de tallos en Ba fue baja en todas las asociaciones, en promedio de 225 tallos m-2. La mayor densidad de tallos en pasto Ov-Ba se presentó en otoño e invierno. Independientemente de la asociación en la estación de primavera se encontró mayor peso por tallo con 0.30 y 0.42 g tallo-1, en Ov y Ba y menor en invierno con 0.13 y 0.14 g tallo-1, en Ov y Ba, respectivamente. En conclusión, la dinámica de población de tallos de pasto ovillo tendió a mantenerse; en contraste, en pasto ovillo solo y ballico perenne disminuyó la población de tallos.