Plataforma virtual Moodle y su influencia en el aprendizaje en los alumnos del segundo grado del área Educación para el Trabajo: Computación de la Institución Educativa Andrés de los Reyes – Huaral 2016

La investigación titulada “Plataforma Moodle y su influencia en el aprendizaje de los alumnos del segundo grado del área Educación para el Trabajo en la Institución Educativa Andrés de los Reyes. El objetivo general de la investigación fue determinar la influencia de la plataforma virtual Moodle en el aprendizaje de los alumnos del segundo de secundaria de la Institución Educativa Andrés de los Reyes- Huaral 2016. El método que se utilizó fue hipotético deductivo, nivel de investigación cuasi experimental y el enfoque es cuantitativo. La población fue censal constituido por 30 estudiantes, es de tipo no probabilístico que constituyeron los mismos elementos de análisis. El instrumento que se utilizó fue cuestionario. Para la validez del instrumento se utilizó el juicio de expertos y para la confiabilidad del instrumento se utilizó la prueba de Kuder Richardson con 0.81 de resultado. Se aplicó la prueba estadístico U de Mann Whitney en el software SPSS 21, los resultados fueron que existe influencia significativa de la variable independiente plataforma Moodle sobre la variable dependiente aprendizaje del área Educación para el Trabajo; antes de aplicarse tanto el grupo de control como experimental presentan condiciones iniciales similares (U-Mann-Whitney=438,500 y p=0. 864). Sin embargo, luego de usarse la plataforma virtual Moodle, se obtiene diferencias entre el grupo de control y experimental (U-Mann-Whitney=132,500 y p=0.00). Por lo tanto la plataforma Moodle mejora el aprendizaje del área Educación para el Trabajo

Estrés por calor en ganado lechero con énfasis en la producción de leche y los hábitos de consumo de alimento y agua. Revisión

The negative impact of heat stress (HS) in dairy cattle results in considerable economic losses at world level, as it reduces the milk production, reproductive efficiency, and productive life in the cows. In addition, the continuous genetic improvement results in highly productive cows, which are, however, less tolerant to HS because they produce greater metabolic heat. This, together with global warming, will turn HS into a hard-to-control challenge for the daily industry. In response dependent on the degree of HS, the dairy cattle carry out a series of physiological, metabolic and behavioral adjustments as thermoregulatory mechanisms for removing excess body heat and reducing the endogenous production of body heat, in order to maintain the normothermia. However, fertility and milk secretion decrease as a direct effect of hyperthermia and an indirect effect of lower dietary nutrient intake. Food and water intake are closely associated to the reduction of the productivity of dairy cattle exposed to HS. Notably, the impact of HS on productivity of dairy cattle varies among breeds, among which Bos taurus, particularly the Holstein breed, are less tolerant to HS. The identification of genes associated to thermotolerance utilized in selection programs using genetic markers to breed high milk-producing cows in warm climates is currently being studied. Therefore, the purpose of this review is to carry out a comprehensive analysis of the effects of HS on milk production, activation of thermoregulatory mechanisms and feed intake behavior in dairy cattle.El impacto negativo del estrés por calor (EC) en la ganadería lechera repercute en cuantiosas pérdidas económicas a nivel mundial, dado que reduce la producción de leche, la eficiencia reproductiva y la vida productiva de las vacas. Adicionalmente, el mejoramiento genético continuo resulta en vacas muy productivas, pero menos tolerantes al EC debido a que producen mayor calor metabólico. Esto en conjunto con el calentamiento global convertirá al EC en un reto difícil de controlar para la industria lechera. Como respuesta dependiente del grado de EC, el ganado lechero realiza una serie de ajustes fisiológicos, metabólicos y conductuales como mecanismos de termorregulación para disipar el exceso de calor corporal y reducir la producción endógena del mismo, todo dirigido a mantener la normotermia. Sin embargo, la secreción láctea y la fertilidad se reducen por efecto directo de la hipertermia e indirectamente por la reducción en el consumo de nutrientes dietéticos. Los consumos de alimento y de agua están asociados estrechamente con la reducción de la productividad en ganado lechero expuesto a EC. Cabe mencionar que el impacto del EC en la productividad del ganado lechero varía entre razas, siendo las razas Bos taurus menos tolerantes al EC, particularmente la raza Holstein. Actualmente, se investiga en la identificación de genes asociados con la termotolerancia, los cuales son empleados en programas de selección por marcadores genéticos para producir vacas altas productoras de leche en climas cálidos. Por lo tanto, el objetivo de esta revisión es hacer un análisis comprensivo de los efectos del EC sobre la producción de leche, activación de mecanismos de termorregulación y conducta de ingesta en ganado lechero

Gestión del director y clima organizacional en las instituciones educativas de la Red Nº 01 nivel inicial del distrito de Huaral 2014

En la investigación titulada “Gestión del Director y Clima Organizacional en las Instituciones Educativas de la red Nº 01 nivel Inicial del distrito de Huaral 2014. El objetivo general de la investigación fue estudiar la correlación entre la Gestión Director y el clima Organizacional en los docentes de la red Nº 01, Nivel Inicial en el Distrito de Huaral. La metodología que se utilizó para demostrar la hipótesis es hipotético-deductivo, se elaboró en el nivel de investigación es descriptivo correlacional y el enfoque es cuantitativo. La población y muestra censal es de tipo no probabilístico que constituyeron los mismos elementos de análisis que vienen a ser 72 docentes de las Instituciones de la red Nº 01, nivel Inicial en el distrito de Huaral. El instrumento que se utilizó fue el cuestionario aplicado a los docentes. Para la validez de los instrumentos se utilizó el juicio de expertos y para la confiabilidad del instrumento se utilizó alfa de cronbach. Se aplicó el estadístico RHO Spearman en el software SPS 21, los resultados nos demuestran que existe correlación positiva entre las variables estudiadas. Ya que por medio del análisis, comparación y descripción de las variables hemos establecido la correlación entre las variables Gestión del Director y Clima Organizacional, es positiva. Los datos estadísticos que sostienen esta investigación vienen de los resultados obtenidos por la aplicación de los instrumentos a los docentes

Prevalence and risk factors for stillbirths in Holstein cows in a hot environment

Risk factors for stillbirth were studied in a dairy operation in northern Mexico (25°N). Data set consisted of 29406 full term calving records. Factors affecting stillbirths were analyzed using a step-wise multivariable logistic regression models. The predictive indicators of stillbirth risk were: temperature-humidity index (THI) during pregnancy and at calving, season of calving, calf birth weight, gestation length, semen characteristics (conventional or sexed), gender of calves, hour of calving and type of parturition (normal or dystocic). Throughout the study period, 7.3 (95%, confidence interval= 7.0–7.6) of every 100 calving events had a stillborn calf. Stillborns were higher with severe dystocia compared with non-assisted births (29.0% vs. 6.2%, p<0.0001) and calves with birth weights <35 kg compared with heavier calves at calving (19.3% vs. 2.3%, p<0.0001), and was lower in calves whose gestation length was >278 d compared with calves with shorter gestation periods (2.8% vs. 30.0%, p<0.0001). Cows in a severe state of heat stress prenatally and at birth (THI >83 units) had 1.3 higher risk of stillbirths than cows suffering reduced heat stress (p<0.0001). Evidence for a greater (p<0.001) stillbirth rates in cows with parturitions between 18:00 and 19:00 h compared with cows calving during other hours of the day was found (9.1% vs. 7.1%). Together, these results demonstrate that ameliorating heat stress during the peripartum period is an important management practice to reduce stillbirths in Holstein cows in this warm climate. Additionally, a greater attention of parturition around sunset can lower the current stillbirth rates

Usporedba djelovanja korionskog gonadotropina konja (eCG) i estradiol cipionata primijenjenih 24 sata nakon prestanka kontrolirane primjene progesterona kao dijela protokola za sinkronizaciju estrusa i umjetno osjemenjivanje meksičkog Criollo goveda.

Two experiments were conducted to evaluate the effect of administering equine chorionic gonadotropin (eCG) in substitution of estradiol, 24 h after the removal of a progesterone intravaginal device, on estrus and ovulatory response, and pregnancy rates of Rodeo Criollo cows (exp. 1, n = 21) and heifers (exp. 2, n = 39) subjected to a synchronization protocol (estradiol + CIDR + PGF2α) with estrus-detected artificial insemination. All females were inseminated 12 h after detected estrus. In cows, estrus and ovulation response, and maximum pre-ovulatory follicle diameter were similar (P>0.05) between equine chorionic gonadotropin and estradiol groups. However, the time to estrus was shorter (P0.05) in ovulation rate. Both treatments resulted in low pregnancy rates, with a significantly lower (P0,05) u skupinama krava kod kojih je bio primijenjen korionski gonadrotropin ili estradiol. Međutim, u skupini kod koje je bio primijenjen estradiol vrijeme do estrusa je bilo kraće (P0,05) u stopi ovulacije. Oba su postupka dovela do niže stope gravidnosti, pri čemu je smanjenje kod junica kojima je bio primijenjen korionski gonadotropin konja bilo signifikantno (P<0,05). Zaključno, primjena korionskog gonadotropina konja, kao zamjene za estradiol nakon uklanjanja sredstva za otpuštanje progesterona, dovela je u sklopu protokola za otkrivanje estrusa i umjetno osjemenjivanje do povećanog grupiranja estrusa i ovulacije te posljedično veće stope gravidnosti u krava, ali ne i u junica

Effect of climate and insemination technique on reproductive performance of gilts and sows in a subtropical zone of Mexico

The objective of this study was to analyse the reproductive performance of hybrid (Yorkshire x Landrace) gilts/sows in relation to temperature-humidity index (THI) at artificial insemination (AI), season of AI, occurrence of estrus &gt;8 d post-weaning, repeated estrus, insemination technique (cervical, CAI or post-cervical, PCAI) and parity. Data included 8851 reproductive records (1771 for gilts and 7080 for sows) from a pig farm in a sub-tropical zone (THI ranged from 72.9 in January to 81.8 in June). A decrease in pregnancy rate (PR, 89.8 vs 93.0%; P&lt;0.01) and a tendency to decline farrowing rate (FR, 87.9 vs 90.3%; P=0.07) following AI during high THI (&gt;82), compared to AI at &lt;74 THI were observed. The spring and summer season were associated with decreased (P&lt;0.01) PR compared with fall and winter (90.0% vs 93.0%). Likewise, FR decreased in spring and summer compared to fall and winter (88.5% vs. 90.9%). FR was higher (P&lt;0.01) in non-repeat breeders compared with that of repeat-breeders (90.3% vs 76.2%). Litter size increased (P&lt;0.01) from 10.8 ± 3.2 to 11.1 ± 3.1 pigs when the interval from weaning to estrus was &gt;8 d. The insemination technique did not affect PR and FR but the litter size decreased (P&lt;0.05) from 11.3 ± 3.0 to 11.1 ± 2.9 pigs when PCAI was used compared to CAI. This study reaffirms the negative effects of the hot season on reproductive performance of gilts/sows, although thermal stress at AI did not cause foetal losses. Also, there is no advantage in using the PCAI as compared to the CAI in gilts/sows with high numbers of sperm cells per AI

Análisis económico del uso de clorhidrato de zilpaterol en la alimentación de corderas

Con el objetivo de realizar un análisis económico sobre el uso de clorhidrato de zilpaterol en ovinos se realizó una investigación con datos provenientes de la engorda de 24 corderas Dorper - Pelibuey en finalización mediante la técnica de costos, ingresos y rentabilidad. Los animales se dividieron en dos grupos de 12 corderas cada uno: Testigo (T1), alimentados con una dieta basal + 100 g de trigo molido, y (T2), que recibieron la dieta basal + 100 g de trigo molido con 10 mg de clorhidrato de zilpaterol (CZ) cada animal durante 24 horas, por 34 días. El contenido de la dieta tuvo 15.8% de proteína cruda (PC) y 2.8 Mcal/kg de energía metabolizable (EM), con un costo de producción de $3.96 por kg. Las variables de interés fueron peso inicial, peso final, ganancia de peso, conversión alimenticia y peso en canal. Para T1 el costo de producción, ingreso y ganancia/animal, por venta en canal, fueron de$823.1, $918.4 y$95.3, mientras que para T2 fueron de $863.8,$1,111.0 y $247.1, respectivamente. Asimismo,la relación beneficio-costo (RB/C) en canal para T1 fue de 1.11 y para T2 de 1.29. Se concluye que la rentabilidad fue mayor en animales suplementados en la dieta con clorhidrato de zilpaterol en relación con los animales testigo

Zilpaterol hydrochloride improves growth performance and carcass traits without affecting wholesale cut yields of hair sheep finished in feedlot

Growth of the sheep meat industry throughout the world has been slow compared with meat industries of other domestic animals. Therefore, increasing productivity and efficiency of sheep meat production are key factors to enhance the competi- tiveness of this industry (Montossi et al. 2013). The use of β2- adrenergic agonists (β2-AA) as growth promoters has demon- strated to increase sheep meat production by improving protein deposition in muscle (Domínguez-Vara et al. 2013). The use of such technology in the lamb fattening systems could be a nutritional strategy to improve their competitiveness.Fourteen Dorper × Pelibuey ram lambs (initial body weight [BW] = 37.4 ± 1.0 kg and age = 4.5 mo) were housed in individual pens during a 30-d feeding period, and then slaughtered to determine the effects of zilpaterol hydrochloride (ZH) supplementation on productive performance, carcass characteristics and wholesale cut yields. Lambs were assigned under a randomized complete block design (initial BW as blocking factor) to one of two dietary treatments: basal diet without (control) or with 10 mg daily of ZH/lamb. Lambs fed ZH had greater (P ≤ .04) final BW, average daily gain and dry matter intake, but similar (P = .24) feed efficiency compared with control lambs. Hot and cold carcass weight, dressing percentage, longissimus muscle area and leg perimeter were greater (P ≤ .05) for ZH-fed lambs than for control lambs. With exception of blood percentage which decreased (P < .01) with ZH, wholesale cut yields and non-carcass components were unaffected (P ≥ .12) by ZH supplementation. In conclusion, ZH can be used to improve growth rate and dressing percentage, but not to increase wholesale cut yields in feedlot finishing ram lambs.This study was supported by PROMEP-SEP under the thematic network ‘Uso de Promotores de Crecimiento en Ovinos de Pelo (2014–2017

Vaccination programs, parity, and calving season as factors affecting the risk of fetal losses and mummified fetuses in Holstein cows

Aim of the study: To investigate vaccination programs, parity, and calving season as factors affecting the risk of abortion and mummified fetuses in Holstein cows.Area of study: Hot zone of Northeast Mexico.Material and methods: Multiple logistic regression models were used to examine the relationship between peripartum disorders, parity, previous occurrence of abortion, season of calving, vaccination program, incidence of abortion, and mummified fetuses in Holstein cows.Main results: For 7014 pregnancies (2886 cows), the percentage of cows aborting and having mummified fetuses was 17.7% and 1.1%, respectively. As the number of brucellosis vaccinations increased, the incidence of abortion increased (10.4% for a single vaccination and 38.0% for 6 accumulated vaccinations). Abortion for cows having 1-2 previous abortions (56%) and &gt;2 abortions (77%) was fivefold and sevenfold greater (p&lt;0.01), respectively, than that for cows without previous abortion. Other important risk factors for abortion were number of calvings (19.8% for nulliparous and primiparous vs. 13.8% for &gt;3 parturitions; OR=1.7, p&lt;0.01), leptospirosis vaccine application &lt;55 days postpartum (dpp; OR=1.3, p&lt;0.05), viral vaccine application &gt;37 dpp (OR=1.3, p&lt;0.01), brucellosis vaccine application &gt;20 dpp (OR=1.6, p&lt;0.01), and no application of clostridial vaccine (OR=3.7, p&lt;0.01). Significant risk factors for mummified fetuses were application of ≥3 brucellosis vaccinations (OR=3.3, p&lt;0.01), no application of 10-way clostridial vaccine (OR=2.3, p&lt;0.01), &gt;2 previous abortions (OR=18.4, p&lt;0.01), and calving in autumn (OR=0.4, compared to winter, p&lt;0.05).Research highlights: Risk of abortion and mummified fetuses in Holstein cows has been found to be related to vaccination programs