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Introduction: The stimulating effect of the male has been used to synchronize and induce estrus and ovulation in ewes through pheromones secreted by the male, an effective method without the use of expensive commercial hormonal products. Objective: The objective of this study was to evaluate the conception rate, fertility and number of offspring per lambing of a group of 20 ewes and an adult Katahdin breeder with biostimulation by male effect, as well as other indicators such as birth weight and pre-weaning weight gain. Methods: it was an experimental and longitudinal study. The work was carried out in the sheepfold of the Instituto Universitario de la Paz in Barrancabermeja, located in a tropical rainforest region. Synchronization was carried out with the introduction of a 7-year-old breeding stock to the herd and the variation in calf weight was determined every 15 days. Follow-up of gestation was performed by ultrasound check-up every 30 days. Descriptive and inferential statistics were used for data analysis with the Stata 14.0 program. Results and Discussion: 93% of calvings were grouped within 25 days, 19 females were pregnant, 17 calved and 2 had embryo loss, the conception rate was 95%, fertility 85% and the number of offspring per calving was 1.35. The average birth weight of calves was 3.8 kg, single and multiple birth calves had a birth weight and preweaning day weight gain respectively of 3.9 kg, 273 g and 3.67 kg, 193 g. Both characteristics showed significant statistical differences (P<0.05). In Katahdin ewes, similar results were reported in one breeding season of evaluation. Conclusion: the male effect allowed to agglutinate calving in a short time, proving its effectiveness as a natural synchronization method. Reproductive results demonstrate the good adaptation of Katahdin ewes to the environmental conditions of the low tropics. Birth weight and preweaning weight gain variables were within the normal range for the breed. [ABSTRACT FROM AUTHOR]

Introduction: Heat stress in sheep is the main physical risk factor for the animal's physiological imbalance. The requirements for water, energy, proteins, minerals, and vitamins are essential for growth, production, reproduction, and thermodynamic maintenance between the animal and environmental conditions. Objective: To study the effect of heat stress on plasma protein concentration in Katahdin sheep. Methods: The research was carried out at the Santa Lucia Research Center's Ovine Academic Research Unit. It was an experimental study with a unifactorial design. Sixteen adult Katahdin sheep with an average weight of 50 kg were used, which were managed under a semi-stabling system. Temperature samples were taken three times a week (Monday, Wednesday, and Friday), in the morning at 10 am and in the afternoon at 4 pm, using a thermo-hygrometer to measure ambient temperature. Blood samples were collected on days 30, 45, and 60, at 7 am and 4 pm. Blood chemistry tests were performed by colorimetry using a semi-automated BA-88A Mindray analyzer. Data analysis was carried out using descriptive and inferential statistics. Results and Discussion: Regarding ambient temperature, a significant difference was observed (AM=28.3 °C and PM=34.8 °C), with p=<0.0001. For total proteins, the t-student test showed p=0.0011, with plasma protein levels (AM=5.8 mg/dl and PM=6.3 mg/dl). For Albumin, the t-student test showed P=0.0011, (Albumin AM=3.2 mg/dl and PM=3.4 mg/dl). In the afternoon hours, the sheep were under heat stress, as hair breeds begin to experience signs of hyperthermia at temperatures =30 °C. It can be inferred that the activation of physiological adjustments in haired sheep to maintain normothermia in warm climates is closely related to changes in blood analyte levels. Conclusion: Although there were significant differences between plasma protein concentrations throughout the day, all values are within the normal reference ranges for haired sheep. [ABSTRACT FROM AUTHOR]

Introduction: Good seminal quality is necessary for cryopreservation to achieve proper post-thaw sperm survival, especially when it benefits endangered breeds. Functional tests that assess different characteristics within the same spermatozoon, such as the Sperm Functional Competence Test (SFCt; plasma membrane integrity, membrane functionality, acrosomal integrity and sperm morphology), promise greater precision in identifying an optimal subpopulation. Objective: To set a new SFCt and determine the association with ejaculates of good (GFE) and poor (PFE) freezability in semen from Chino Santandereano breed bulls. Methods: The study was conducted at the Laboratory of Animal Reproductive Biotechnology (LABRA) of the Paz University-UNIPAZ in Barrancabermeja-Santander. Thirty ejaculates from ten bulls were cryopreserved, then classified by freezability level using two-step cluster analysis based on variables: membrane integrity, sperm morphology, and sperm motility using fluorescence, phase-contrast, and computer-assisted sperm analysis (CASA) respectively. The SFCt outcomes in fresh and frozen-thawed semen and compared between both freezability groups through IBM Statistics 27 software. Correlation analysis was conducted for all variables. Results and Discussion: Statistic analysis revealed a positive and highly significant correlation (P<0.01) between fresh SFCt and post-thaw motility (r: 0.581), and post-thaw membrane integrity (r: 0.594). This may be because the SFCt evaluates sperm resistance to hypotonic shock, a fundamental characteristic of cells in the freezing protocol. There was no significant difference (P>0.05) between GFE and PFE groups in SFCt levels in fresh semen. However, post-thaw SFCt showed highly significant differences (P<0.01) between freezability groups. The SFCt, by evaluating different sperm characteristics simultaneously, replaces motility and membrane integrity analysis for ejaculate classification by freezability. Conclusion: The SFCt evaluated in fresh semen is related to post-thaw sperm variables but does not predict freezability. However, this test, when performed postthaw, serves to classify ejaculates by freezability, replacing conventional análysis. [ABSTRACT FROM AUTHOR]

Antecedentes: la interacción entre espermatozoide y el plasma seminal promueve cambios en la membrana espermática que implican una redistribución de lípidos a través de procesos bioquímicos y fisiológicos. Dado que el colesterol es el responsable de la fluidez de la membrana espermática, hay una estrecha relación entre el colesterol y factores como la capacitación y la viabilidad espermática en procesos de criopreservación. Objetivo: determinar la relación entre los niveles de colesterol y parámetros de la calidad seminal en espermatozoides de toros Chino Santandereano. Métodos: la investigación se desarrolló en el Laboratorio de Biotecnología Reproductiva Animal del Instituto Universitario de la Paz-UNIPAZ en Barrancabermeja (Santander) siguiendo el método observacional de las variables movilidad (Mg), movilidad progresiva (Mp), vitalidad (Vt), espermatozoides funcionalmente competentes (EFC) y los niveles de colesterol espermático en 30 eyaculados de 10 toros en iguales condiciones de manejo nutricional y sanitario. La valoración de la movilidad espermática (general y progresiva), la vitalidad y los EFC se realizó mediante el sistema computarizado de análisis seminal (CASA). Los niveles de colesterol se determinaron mediante espectrofotometría semiautomatizada. La evaluación de la normalidad y la homocedasticidad de datos sugirieron la utilización de estadística no paramétrica. Resultados: la prueba de Pearson evidenció una correlación significativa entre las cantidades de colesterol y el EFC (r = -0,473; p < 0,01) y el colesterol y la movilidad general (r = -0,382; p < 0,05); sin embargo, se evidenció baja correlación y significancia entre el colesterol y la movilidad progresiva (r = -0,152; p > 0,05) y el colesterol y la vitalidad (r = -0, 251; p > 0,05). Conclusiones: los resultados sugieren una relación interesante entre la calidad seminal y la capacidad de los espermatozoides para liberar colesterol. Sin embargo, es necesario complementar la valoración del colesterol con otras pruebas adicionales con el fin de explorar mejor los altos niveles de calidad seminal en toros Chino Santandereano en semen fresco y descongelado [ABSTRACT FROM AUTHOR]

Antecedentes: los probióticos son una opción favorable para el potenciamiento productivo animal Objetivo: evaluar ganancia de peso (GP), mortalidad (M) y cambios morfométricos en microvellosidades de intestino delgado (ID) y grueso (IG) en pollos de engorde, frente adición de probióticos en el agua. Métodos: en el Instituto universitario de la Paz, se siguió a 240 pollos de engorde de línea Cobb, en condiciones adecuadas para el crecimiento; desde el día 7 hasta el 42 se adicionó de dosis de probióticos, organizándose 4 tratamientos con 60 pollos cada uno, divididos en 3 réplicas con 20 animales; el T0 sin adición, T1: comercial recomendada, T2: recomendada doble; T3: recomendada triple. Los datos para % de M, tabulados diariamente; GP, datos de peso cada 7 días a todos los animales hasta día 42. Al final del estudio al azar 10 pollos de cada réplica sacrificados al azar por método tradicional, para el estudio histológico, siendo un total de 120 pollos por los 4 tratamientos, extrayéndose un corte de 1 cm por 1 cm, porción media de ID y una porción en la parte inicial del ciego, preservadas en formaldehido al 10 %, enviadas y procesadas en histopatología de la Universidad Industrial de Santander. La lectura de las placas se llevó a cabo con óptico micrométrico. El análisis de datos estadística paramétrica, T student, descriptiva, ANOVA y Tukey. Resultados: altura de vellosidades ID, diferencias significativas (p > 0,05) entre T0: 511,11 μm; con T1: 773,33 μm; T2: 797,33 μm y T3: 793,33 μm, ancho de vellosidades no mostró diferencias (p < 0,05); T0: 118,44 μm; T1: 109,11 μm; T2: 126,33 μm y T3: 120,11 μm. En IG, no hay diferencias (p < 0,05), T0: 122,8 μm, T1: 131,2 μm, T2: 144 μm y T3: 163,20 μm; en el ancho no hay diferencias (p < 0,05), T0: 49,00 μm, T1 46,53 μm, T2: 48,60 μm y T3: 52,20 μm. GP se observó diferencia (p > 0,05) entre T0 y T1, en el caso de T0: 1936,9 gr, T1: 2120,9, T2: 1975,6 gr y T3: 1974,6 gr. La M, los siguientes %: T0: 21,7 %; T1: 8,3 %; T2: 11,7 %; T3: 11,6 %. Conclusiones: los probióticos son una buena elección para mejorar los parámetros productivos y biológicos de los pollos de engorde generando producciones limpias cuidando el bienestar animal. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencias Pecuarias is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Ciencias Pecuarias is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Ciencias Pecuarias is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Colombiana de Ciencias Pecuarias is the property of Universidad de Antioquia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)