Browsing by Author "Dutan Sanango, Jorge Bolivar"

Now showing 1 - 6 of 6

Accuracy of ultrasound and visual inspection in antral follicular count in crossbred Holstein cows raised under grazing systems at high altitude
(2023) Astiz, Susana
The objective of this research was to investigate the diagnostic accuracy of post- mortem ultrasound in antral follicle count (AFC) determination and compare it with visual AFC in grazing crossbred Holstein cows, at high altitude in Ecuador. Pre- mortem blood from 80 cows was collected, and AFC and ovarian characteristics were ana-lysed post- mortem by ultrasound and visual techniques. AFC counts were stratified as high, medium or low by terciles. Mean AMH concentration in pre- mortem blood was 280.1 ± 15.53 pg/mL. The AFC obtained by visual inspection (26.9 ± 9.49 follicles) was 23.8% higher than by ultrasound (20.5 ± 7.53 follicles) in all ovaries. Body condi-tion score, age and weight of the cattle did not interact with the count technique. In the low AFC group, visual inspection and ultrasound provided similar AFC results. However, in the Medium- and High-AFC groups, AFC by ultrasound was 14.9% lower than AFC by visual inspection. We confirm that ultrasound can be used with great accuracy for AFC >3 mm (close to the resolution limit) in grazing crossbred Holstein cows at high altitude.
Capacidad de reinicio de la meiosis de ovocitos provenientes de folículos de varios tamaños obtenidos de ovarios de camal
(2019) Ayala Guanga, Luis Eduardo; Palacios Cedeño, Tito Emmanuel; Calle Ortiz, Guido Rigoberto; Rodas Carpio, Ermes Ramiro; Dutan Sanango, Jorge Bolivar; Murillo Apolo, Yury Agapito; Samaniego Campoverde, Jorge Xavier
The competence of oocytes according to follicle size to restart meiosis was evaluated. The follicles were measured and classified as Group 1 (G1 <4 mm), Group 2 (G2 4-8 mm) and Group 3 (G3 >8 mm). The aspiration was performed by group with a 21G needle connected to a vacuum pump, with a pressure of 65 mmHg. The complex oocyte clusters (COCs) recovered were classified as suitable and unsuitable to produce embryos in vitro, according to the characteristics of the cumulus and the cytoplasm. Eligible and unsuitable COCs were assessed with the Brilliant Cresyl Blue (BCB) and were classified into BCB+ and BCB-. In vitro maturation (IVM) was carried out in microdroplets, incubated in a 5% CO2 chamber, 38.5 °C and 90% humidity for 24 hours. The meiotic progression was determined by extrusion of the polar corpuscle by epifluorescence under an inverted microscope. Oocyte morphometry was established using a high definition camera (Excelis AU-600-HD) and software (AmScope v.3.7). The recovery percentage of oocytes was greater than 63%. The G2 follicles provided a higher percentage of eligible COCs (65.7%), where 59% of this group was classified as BCB+. The fit oocytes of G1 and G2 resumed meiosis by 75%. In addition, it was observed that oocytes after IVM reduced their diameter. It is concluded that follicle oocytes between 4-8 mm (G2) provide a higher percentage of mature COCs; however, 50% of follicles <4 mm (G1) are a promising source of viable oocytes, so they should be used for in vitro embryo production.
Características morfométricas de las razas criollas encerado, colorado, atigrado y pintado de la región interandina del Ecuador
(ALPA, 2018) Dután Sanango, Jorge Bolívar; Murillo Apolo, Yury Agapito; Rodas Carpio, Ermes Ramiro; Vázquez Mosquera, Juan Mesías; Calle Ortiz, Guido Rigoberto; Nieto Escandón, Pedro Emilio; Ayala Guanga, Luis Eduardo; Ortega Herrera, Vanessa Viviana; Dutan Sanango, Jorge Bolivar
Se caracterizó la morfometría de las razas Criollas Encerado, Colorado, Atigrado y Pintado de la región interandina del Ecuador, donde se evaluaron 106 vacas multíparas, edad promedio 5,3±0,19 años, número de partos 2,9±0,21 y condición corporal 3,1±0,11. Para establecer las características morfométricas se analizaron 21 medidas corporales, 4 caracteres de ubre, con el bastón zoométrico, cinta bovinométrica, calibrador, para determinar el peso se utilizó el método de Quetelet; además, 9 variables fanerópticas por observación directa. El análisis estadístico se realizó a través del Paquete Estadístico SPSS®, versión 22, en el cual se analizaron frecuencias, estadígrafos principales, análisis de varianza y chi cuadrado. Para la determinación de los biotipos se aplicó clúster bietápico basado en el color de capa, altura a la cruz, perímetro torácico y peso. Se estableció que el ganado criollo tiene una representatividad del 4% en la zona de estudio. Dentro de este genotipo se establecieron 4 biotipos; Encerada (28%), Colorada (14%), Atigrada (9%) y Pintada (55%), con características morfoestructurales similares entre sí (P>0,05), como altura a la cruz entre 120,9±1,11 - 121,5±0,80cm, peso 334,2±11,13 - 356,0±23,33kg; perímetro torácico 163,39±1,79 - 168,33±3,43cm y perímetro de caña 16,0 ±0,34 - 17,2 ±0,67cm. Los biotipos Encerada y Pintada presentaron tendencia lechera (96,4%) con un perfil rectilíneo de 75,0% y 88,5% respectivamente y proporciones longilíneas, superiores al 92,9%, a diferencia de la Colorada (42,9%) y Atigrada (33,3%) con un perfil convexilineo y caracteres de producción mixta de 14,3% y 33,3% para cada uno de ellos. Se concluye que los biotipos criollos tienen tendencia productiva lechera y doble propósito y la única diferencia entre ellos es el color de capa.
Effect of Follicle-stimulating hormone administered epidural on ovarian response and hormone profile in Holstein cows
(2023) Ayala Guanga, Luis Eduardo
The study was carried out in crossbred Holstein cows, raised in the high tropics of Ecuador. The effect of single dose epidural follicle-stimulating hormone (FSH) administration on ovarian response, structure number and collected transferable embryos was determined; as well as the hormonal profile. Two treatments (T) were tested: T1 (n=14; conventional) received 300 mg of FSH divided into 8 decreasing doses intramuscular (IM), on days (d) 4, 5, 6 and 7 of the protocol in the morning and in the afternoon, in T2 (n=14; epidural) 200 mg of FSH was administered in a single epidural dose on d 4. In a second instance, FSH levels were determined at 0, 2, 4, 12, 24, 26, 28, 36, 48, 50, 52, 60, 72, 74, 76 and 84 h of the superovulation (SOV) protocol. The number of antral follicles (AF) that responded to the application of FSH was similar (P>0.05) in the two Treatments (T1=17.9± 1.55 follicles; T2=14.3 ± 1.69 follicles); as well as their size. However, the animals of T2 (5.8±1.83 CLs: corpus luteum) presented 2.4 times fewer CLs than those observed in T1 (13.9±1.57 CLs), with a statistical difference (P<0.05). A greater number of structures was obtained in T1 (9.4±1.05) than T2 (4.5±1.29), and the same occurred with the transferable embryos. FSH reached the highest values at 4 h and remained at similar concentration throughout the first 50 h. Then the concentration in T2 decreased to basal values lower than those observed in T1. In conclusion 200 mg of FSH applied via epidural causes an superstimulation similar to the conventional protocol: however, the number of ovulations and transferable
Relación de la hormona anti-mülleriana con la cantidad y calidad de ovocitos colectados por aspiración ecoguiada en vaquillas Holstein
(2023) Dutan Sanango, Jorge Bolivar; Garay Pena, Gabriela Sofia; Pesántez Pacheco, José Luis; Jacome Aucay, Andres Santiago; Ayala Guanga, Luis Eduardo; Samaniego Campoverde, Jorge Xavier
The experiment had two phases, the first one determined the relationship between the antral follicle count (AFC) and the concentration of Anti-Müllerian hormone (AMH) valued on the day the follicular wave restarted in 61 crossbred Holstein heifers, raised on farms, from the high tropics of Ecuador. The second phase compared the AFC assessed on the day of ultrasound-guided aspiration (OPU); as well as the quantity and quality of Cumulus Oocyte Complexes (COCs) recovered in animals with high (n=8) and low (n=8) concentrations of AMH. Follicular wave synchronization in the first phase of the study was performed with estradiol benzoate plus an intravaginal progesterone (IVD) and prostaglandin (PG) implant. The AFC and the taking of the blood samples in the first phase of the experiment were carried out on day 11 of the protocol. AMH cut-off values of greater than 0.12 ng·mL-1were established for the high AMH group and 0.05 ng·mL-1for the low AMH concentration group. The AMH concentration on day 0 (start of the follicular wave) was 0.13 ± 0.01 ng·mL-1, with an AFC of 17.31 ± 0.69 follicles and a high and positive correlation between AMH and the AFC of r=0.93; P<0.001. In the second phase of the experiment, it was observed that the heifers with a high concentration of AMH had double the number of follicles and COCs compared to those with a low concentration; however, the recovery rate was similar (57 %) in the two groups. The existence of a high and positive correlation between AFC and AMH concentration was confirmed; Furthermore, a strong relationship was observed between AMH and the quantity and quality of COCs recovered by OPU. Heifers with greater than 12 ng·mL-1should be selected as oocyte donors, since they provided double the COC's suitable for the production of embryos in vitro (PIVE), which will influence the quantity and quality of embryos obtained at the end of the PIVE.
Relationship between the concentration of anti-Müllerian hormone and antral follicle count in pasture-managed Holstein cows in the high tropics
(2022) Fernández Fonseca, Hug; Samaniego Campoverde, Jorge Xavier; Lopez Cabrera, Rodrigo Xavier; Perea Ganchou, Fernando Pedro; Astiz, Susana; Ayala Guanga, Luis Eduardo; Pesántez Pacheco, José Luis; Dutan Sanango, Jorge Bolivar
We evaluated the relationship between plasma levels of anti-Müllerian hormone (AMH) and the number of antral follicles at the restart of the follicular wave in crossbred Holstein cows reared under extensive grazing systems over 2500 m above sea level. The study included 140 cows from 15 farms that were in average at the 75.3 ± 2.10 d post partum. Animals were synchronized according to the following regime: day 0 = intravaginal progesterone releasing device (IPD) + estradiol benzoate (EB); day 7: withdrawal of IPD + prostaglandin; and day 8: EB, for restart of the follicular wave on day 11. On this day 11, antral follicle counts (AFCs) were made by transrectal ultrasound, and a plasma sample was taken for the determination of AMH. The mean AMH plasma level was 0.06 ± 0.03 ng/ml and the mean AFC was 17.26 ± 0.38 follicles. A strong positive linear correlation was found between these two variables (r = 0.783, r = 0.613, P < 0.0001). Cows were categorized according to AMH concentration as high (>0.09 ng/ml), intermediate (0.09–0.05 ng/ml) or low (<0.05 ng/ml). Cows with high AMH presented a higher AFC (25.0 ± 2.21 follicles) than those with low AMH (14.08 ± 2.68 follicles; P < 0.001. Our results suggest that the cut-off value of AMH = 0.09 ng/ml may be useful for selecting donors in multiple ovulation embryo transfer programs involving cows with these characteristics. Our data further suggest that AMH plasma concentration correlates with AFC and can be used as an endocrine biomarker of the number of antral follicles present at a given moment of the estrous cycle in crossbred Holstein cows raised at altitudes above 2500 m.