El objetivo del estudio fue determinar el efecto de tres curvas de congelación sobre la viabilidad pos-descongelación de espermatozoides colectados del conducto deferente de llamas. Se utilizaron seis llamas machos con desviación quirúrgica de los conductos deferentes. Las muestras de los seis machos se mezclaron para su procesamiento (pools) y se diluyeron con Tris-yema de huevo. Se procedió al enfriamiento hasta los 5 °C donde se completó la dilución (dilutor con glicerol) y se mantuvo por media hora (fase de equilibrio). Las muestras en pajillas de 0.25 ml fueron sometidas a congelamiento utilizando una tasa de descenso de temperatura de -20°C/min hasta llegar a -80°C (TI), a -100 °C (TII) y a -120 °C (TIII) en 4, 5 y 6 minutos, respectivamente, para finalmente almacenarlas en nitrógeno líquido. Las muestras fueron colectadas durante tres meses (n=19 pooles). Se determinó la motilidad total (motilidad progresiva, circular, oscilatoria), viabilidad y funcionalidad de membrana luego de la colecta, en la fase de equilibrio y al descongelamiento. Se observó una disminución significativa (p˂0.05) en todas las características espermáticas evaluadas en las muestras equilibradas respecto a las muestras luego de la colecta. Se obtuvo una correlación alta positiva entre viabilidad y motilidad total (r2=0.78) y en fase de equilibrio entre funcionalidad de membrana y motilidad total (r2=0.881) En las muestras descongeladas, la motilidad total y viabilidad fueron significativamente mayores en las muestras congeladas con la curva de congelamiento TIII respecto al TI (p=0.041 y p=0.003, respectivamente). No se observaron diferencias significativas en la funcionalidad de membrana entre las tres curvas de congelamiento (p˃0.27). En conclusión, la curva de descenso de la temperatura hasta los -120 °C utilizando una tasa de -20 °C/min sería la más adecuada para criopreservar espermatozoides de llama obtenidos a partir de la desviación de los conductos deferentes.

B-mode and Doppler ultrasonography in ruminants, as a technique has allowed establishing new concepts on the reproductive physiology of females, through the study of follicular dynamics and morphometry of the corpus luteum, therefore, the objective was to characterize by means of B-mode and Doppler ultrasonography the corpus luteum in recipient llamas. Thirty-seven recipient llamas were used (27 for B-mode ultrasonography and 10 Doppler) that were synchronized by applying buserelin acetate 0.0096 mg, nine days later 0.048 mg of prostaglandin F2α analog was applied two days later, the second dose of buserelin acetate was applied at the same dose to guarantee ovulation and subsequent formation of the corpus luteum, the evaluation in mode B of the morphometry consisted of observing the echotexture, area, diameter and volume of the corpus luteum with the use of a SonoStar SS-8 ® ultrasonograph at 6.5 MHz frequency and 6 cm depth equipped with a transrectal linear transducer; using the same technique with a Draminski 4Vet ® Doppler equipment, the percentage of luteal area of vascularization (% AVL) was determined. The data were subjected to a descriptive analysis being 0.119±0.032 cm2 of area, 12.7±1.7 mm of diameter and 0.84±0.32 cm 3 of CL volume, to determine the relationship between metric measures the Pearson correlation was used observing a positive relationship between area/diameter of 0.7506, area/volume of 0.9289 and diameter/volume of 0.6602, observing a high positive correlation between area and volume, finally the % AVL characteristics was 34.97 for the CL of recipient llamas. In conclusion, the morphometric characteristics evaluated in mode B (area, diameter and volume) have a positive correlation and the % AVL could be applied as a tool in the efficient reproductive management for the selection of recipients in camelids, understanding that it is one of the first reports of these characteristics in llamas 2021. Journal of the Selva Andina Animal Science ® . Bolivia. All rights reserved.

B-mode and Doppler ultrasonography in ruminants, as a technique has allowed establishing new concepts on the reproductive physiology of females, through the study of follicular dynamics and morphometry of the corpus luteum, therefore, the objective was to characterize by means of B-mode and Doppler ultrasonography the corpus luteum in recipient llamas. Thirty-seven recipient llamas were used (27 for B-mode ultrasonography and 10 Doppler) that were synchronized by applying buserelin acetate 0.0096 mg, nine days later 0.048 mg of prostaglandin F2α analog was applied two days later, the second dose of buserelin acetate was applied at the same dose to guarantee ovulation and subsequent formation of the corpus luteum, the evaluation in mode B of the morphometry consisted of observing the echotexture, area, diameter and volume of the corpus luteum with the use of a SonoStar SS-8 ® ultrasonograph at 6.5 MHz frequency and 6 cm depth equipped with a transrectal linear transducer; using the same technique with a Draminski 4Vet ® Doppler equipment, the percentage of luteal area of vascularization (% AVL) was determined. The data were subjected to a descriptive analysis being 0.119±0.032 cm2 of area, 12.7±1.7 mm of diameter and 0.84±0.32 cm 3 of CL volume, to determine the relationship between metric measures the Pearson correlation was used observing a positive relationship between area/diameter of 0.7506, area/volume of 0.9289 and diameter/volume of 0.6602, observing a high positive correlation between area and volume, finally the % AVL characteristics was 34.97 for the CL of recipient llamas. In conclusion, the morphometric characteristics evaluated in mode B (area, diameter and volume) have a positive correlation and the % AVL could be applied as a tool in the efficient reproductive management for the selection of recipients in camelids, understanding that it is one of the first reports of these characteristics in llamas 2021. Journal of the Selva Andina Animal Science ® . Bolivia. All rights reserved.

Trout production in Peru has export potential. However, there are no fry available to maintain production throughout the year and there is also a lack of egg production at certain times of the year. Therefore, the alternative is to cryopreserve semen for the non-reproductive season. The objective of the study was to determine the influence of freezing temperature on the quality of rainbow trout semen. The semen of 12 reproductive males was collected in the facilities of the Chucuito Research and Production Center of the National University of the Altiplano of Puno, which underwent a macroscopic, microscopic pre and post thaw seminal evaluation and the fertility rate was measured. Due to the effect of three freezing temperatures (-80 °C, -100 °C, -120 °C), cryopreservation had a decline curve of -20 °C / min. The fresh seminal parameters were similar to those reported by other researchers. While freezing had unfavorable effects on semen quality, the best results for activation time (51.33 sec) and vitality (35.33%) were obtained with -100 °C, but the higher motility was obtained with -120 °C (36.33%). Regarding fertility, the higher rate was obtained with -100 °C (70.97%), followed by -80 °C and -120 °C in which 68.86% and 64.34% were obtained, respectively. In conclusion, the results suggest that the tolerable freezing temperature of rainbow trout semen is around -100 °C, which is shown as a favorable alternative for the reproductive management of rainbow trout under natural hypobaric conditions of the Peruvian highlands