Semen cryopreservation from angora bucks under artificial photoperiodic treatments

AISEN E; ALVAREZ H; MEDINA V; VENTURINO A; MORELLO H

Madrid- España

Simposio; 10th International Symposium on Spermatology; 2006

International Symposium on Spermatology

Sperm quality in mate Angora goats is highly seasonal in response to change in the photoperiod. Thus, it is difficult to obtain semen with good cryopreservation ability outside the breeding season. Artificial photoperiodic cycles have been used to control reproductive activity in other seasonal breeds. In those cases, the stock of semen was greatly increased, especially in the artificial insemination centers. The aim of this study was to apply artificial photoperiodic treatments to improve the sperm recovery after the freeze-thawed process. 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 (g hs light), starting in March 2002. For each buck, one ejaculate was obtained and processed weekly during the 2003 - 2004 breeding and non-breeding seasons. Freeze-thawing tolerance of spermatozoa was evaluated by sperm motility (MI), supravital stain (Eo) and hyposmotic swelling test (HOST). The ejaculates were obtained by artificial vagina, centrifuged twice in Krebs-Ringer solution, diluted in skim milk-glucose-glycerol extender, packaged in 0,25 ml French straws and frozen in nitrogen vapors. At non-breeding season, differences (p<0.05) in cryopreservation ability between natural and artificial photoperiadic groups were observed (MI: 38,28% vs. 47,81%; Eo: 33,38% vs. 54,50%; HOST: 25,50% vs. 35,37%, respectively). In addition, the sperm doses production per year was higher in treated bucks. We conclude that artificial photoperiod applied to Angora bucks allows to obtain frozen semen during the whole year, with higher preservation of the sperm cell membranes.