Artificial photoperiodic cycles for semen collection from male angora goats during non-breeding season

MORELLO H; ALVAREZ H; MEDINA V.; BOGADO D; QUINTANA M; VENTURINO A; AISEN E

Colonia del Sacramento, Uruguay

Simposio; Satellite Symposium on Reproduction in Small Ruminants 2004, for the 15th International Congress on Animal Reproduction (ICAR-2004); 2004

ICAR

Reproductive activity in Angora bucks is highly seasonal in response to change in the photoperiod. Testicular size, androgens and sperm production is higher in the breeding season (February to June in the Southern Hemisphere), as compared to the non-breeding season. Therefore, it is difficult to collect semen outside the breeding season. Artificial photoperiodic cycles have been used to control reproductive activity in other seasonal breeds (Chemineau et al., Reprod. Nutr. Dev. 28 (2B) 409-422, 1988). The aim of this study was to apply artificial photoperiodic treatments to decrease the seasonal variation of testicular size and semen production of male Angora goats. Ten adult Angora bucks were divided into 2 groups. Control males perceived the natural variation of photoperiod (38° 56? S). Another group was subjected to two months of long days (16 hs light), followed by two months of short days (9 hs light), starting in March 2002. Testicular circumference and quantitative seminal parameters (volume, sperm concentration and total number of spermatozoa per ejaculate) were measured weekly during the 2003 breeding and non-breeding seasons. The mean differences were determined using t-tests. In the treated group, testicular circumference, sperm concentration and total number of spermatozoa per ejaculate during the non-breeding season were significantly different from the control group (see table). Although the scrotal circumference during the breeding season was higher in the control group, we found non significant differences in the other seminal parameters. The photoperiod treatment used (long days + short days) decreased the seasonal fluctuation in scrotal circumference. In consequence, the sperm production (measured as total spermatozoa per year) was higher than non-treated bucks. This would allow more seminal doses to be obtained from males during a year, and the stock of semen could be greatly increased in the artificial insemination centers. (Leboeuf et al., Anim. Reprod. Sci. 62, 113-141, 2000).