Seasonal variation in semen quality of lacaune rams in Brazil

Abstract

Little is known regarding the seasonal semen production of Lacaune rams in southern Brazil. Thus, the aim of this study was to evaluate semen quality and production of Lacaune rams maintained in Rio Grande do Sul (RS). Semen was collected using an artificial vagina, from 12 rams (1 to 4 years of age), kept under intensive conditions. The quantitative and qualitative characteristics of the semen and scrotal circumference of each ram were recorded, from the winter of 2002 to the spring of 2003. Seasonal variations were recorded in almost all the monitored semen characteristics and in scrotal circumference. Sperm concentration was the only semen characteristic evaluated that did not show seasonal variation. Sperm volume varied between 1.1 ± 0.4 mL (winter of 2002) and 1.5 ± 0.4 mL (autumn of 2003). Total number of sperm per ejaculate varied between 4.0 ± 3.3x10(9) (winter of 2002) and 5.7 ± 3.3x10(9) (summer of 2003). For scrotal circumference records, in 2002 significant differences between seasons were observed. Significant differences were also found in accordance with the age of rams (P < 0.05) in the winter of 2002. Results showed improvement in motility, concentration and volume of the sperm during summer and autumn when compared to spring and winter. So, in this region of Brazil summer and autumn are the more indicated seasons to maximize the utilization of Lacaune rams for reproductive practices. Further studies must be done to evaluate Lacaune semen freezability in these seasons of the year.