ABSTRACT
ABSTRACT Objective. Aimed to describe the characteristics of the onset of puberty in males in Colombian hair ram lambs (Ovino de Pelo Colombiano, OPC), and their crosses with Katahdin and Santa Inés sheep in a farm located in Villavicencio, Meta. Materials and methods. 15 lambs of three biotypes: OPC x OPC (OPC), Santa Ines x OPC (SO) and Katahdin X OPC (KO) from four until 12 months old. Ram lambs were grazing and they had supplementation with commercial salt and water ad libitum. Monthly body weight (BW), scrotal circumference (SC), testicular volume (TV) were measured and testosterone level were determined by Elisa test, and ultrasound of the two testicles was performed to determine the presence of the testicular mediastinum, also evaluating the presence and detachment of the urethral prolongation and then electro ejaculation was performed to determine the macroscopic and microscopic characteristics of the semen. Results. Genotype effect was significant for evolution of body BW, SC, TV over time. The SO and KO crosses presented the highest values in BW, whereas OPC lambs maintained a lower value until the end of the assay. At six months old, the three biotypes presented a minimum concentration of 150 million of sperm per ml with 30% of individual progressive motility. Conclusions. In non-seasonal tropical conditions in Colombia (Orinoquia), depending on the variables included, body weight, testicular development, pennis morphology, semen quality, sperm concentration and testosterone levels, it is postulated that around six months of age, the onset of puberty is displayed in the three biotypes.
RESUMEN Objetivo. Describir las características del inicio de la pubertad en corderos machos (Ovino de Pelo Colombiano, OPC) y sus cruces en una granja ubicada en Villavicencio, Meta. Materiales y métodos. Se evaluaron 15 corderos de tres razas: OPC x OPC (OPC), Santa Inés x OPC (SO) y Katahdin X OPC (KO), a partir de los cuatro meses de edad, cinco corderos por cruzamiento, manejados en pastoreo rotacional, con sal mineralizada comercial y agua a voluntad. Mensualmente hasta los doce meses de edad, se evaluó el peso corporal (PC), circunferencia escrotal (CE), volumen testicular (VT), y se determinó la concentración de testosterona en suero mediante la prueba de Elisa, se determinó la presencia del mediastino testicular mediante ecografía y se evalúo el desprendimiento de la prolongación uretral. Finalmente se determinaron las características macroscópicas y microscópicas del eyaculado. Resultados. El efecto racial o de cruzamiento fue significativo para los resultados del PC, CE y VT en el tiempo. Los cruces OPC y KO presentaron los valores más altos en PC, mientras que los corderos OPC mantuvieron un valor menor de PC hasta el final de la investigación. Se realizaron al menos cuatro evaluaciones seminales hasta la presentación de una concentración mínima de 150 millones de espermatozoides por ml con un 30% de motilidad progresiva individual. Conclusiones. En condiciones tropicales no estacionales en Colombia (Orinoquia), para las variables peso corporal, desarrollo testicular, morfología del pene, calidad del semen, concentración de espermatozoides y niveles de testosterona, se postula que alrededor de los seis meses de edad, se presenta el inicio de la pubertad en los tres biotipos.
Subject(s)
Animals , Testosterone , Sheep , Sexual MaturationABSTRACT
Objective. This study evaluated the effect of age and coasting period over oocyte quality and their posterior development under in vitro conditions from prepubertal Bos indicus crossbred donors. Material and methods. Donors females received a norgestomet implant and estradiol benzoate. Four days later a unique dosage of 150 IU of eCG was administered. Three coasting periods (24, 48, and 56 h) and four ages (3, 6, 10, and 12 months) were proved. All antral follicles were aspirated and an in vitro culture proceed was done. Results. 439 follicles were aspirated, of which 385 (87.7%) were 2-5 mm, 41 (9.33%) were 5-10 mm, and 13 (2.3%) were 10 mm. After aspiration, a total of 373 oocytes (84.9%) were recovered, finding differences (p<0.05) between averages of 6 (9.3) and 10 months old animals (32.3). 285 (76.4 %) recovered oocytes were subjected to in vitro process. Cleavage values were significantly higher (p<0.05) in 10 (27.1%) and 12 months animals (26.8%). Although the number of transferable embryos was low, there were differences between ages (p<0.05) obtaining a higher percentage in age 3 (12.6%). Conclusions. A coasting period higher than 24 h has a negative effect on oocyte quality. Some oocytes from 3 months old calves were competent for in vitro embryo development; however, higher numbers of embryos were produced from 10 and 12 months of age prepuber females, indicating they have higher competency in vitro.