Research: Season affects free-range frozen poultry semen motility

Spanish researchers in Madrid have presented research on the influence of the season on the freezing of free-range poultry semen, while preserving sperm motility. They conclude that spring is the best time to collect for Mediterranean chicken breeds.

The purpose of study was to examine the seasonal variation in freezing damage in free-range rooster sperm.

Method
Over a period of 1 year, heterospermic semen samples were collected weekly by massage from the roosters of 14 Spanish chicken breeds, all housed under natural photoperiod and climatic conditions. All samples were frozen in straws using DMA as a cryoprotectant, placing them first in nitrogen vapour and then plunging them into liquid nitrogen.

Results
No seasonal effects on fresh sperm quality were found. Neither did season affect the percentage of viable frozen-thawed spermatozoa nor the percentage with an intact acrosome. However, the collection season influenced (p<0.05) most frozen-thawed sperm motility values. The percentage of immotile frozen-thawed spermatozoa was lower (p<0.05) in spring-collected sperm than in summer- or autumn-collected samples. The percentage of spermatozoa showing progressive motility was higher in spring-collected sperm compared with winter-, summer- or autumn-collected samples (p<0.05). The curvilinear velocity (VCL), straight-line velocity (VSL) and average path velocity (VAP) values of spring-collected sperm were also higher (p<0.05).

In conclusion, spring would appear to be the best season for collecting and freezing the semen of free-range Mediterranean chicken breeds.

Source: Reproduction in Domestic Animals