Quality of chilled and cold-stored (5xa0°C) canine spermatozoa submitted to different rapid cooling rates.

PMID 24985357


The aim of this study was to evaluate the sperm quality in chilled canine semen using different cooling rates from room temperature (23xa0°C) to 5xa0°C and subsequently cold-stored at 5xa0°C for up to 96xa0hours. In experiment 1, semen samples from five dogs were pooled, diluted in Tris-fructose-citrate extender with 20% egg yolk and split into four aliquots that were chilled to 5xa0°C using different cooling rates of 2.25, 0.9, 0.45, and 0.2 (control) °C/min. In experiment 2, semen from five dogs was processed individually as described above and split into two aliquots that were chilled to 5xa0°C using rates of either 2.25 °C/min or 0.2 °C/min. In both experiments, the sperm quality (i.e., sperm motility and viability) was evaluated before cooling and after 0, 24, 48, 72, and 96xa0hours of storage at 5xa0°C. The total motility, progressive motility, and quality of movement parameters were assessed using computer-assisted analysis system, and the percentage of viable spermatozoa was determined using flow cytometry (H-42/PI//FITC-PNA). The cooling rate did not influence the sperm quality parameters at any of the evaluation times. All evaluated males showed the same response to chilling semen at a rapid cooling rate. Storage time negatively influenced (Pxa0