Abstract
Interest in the preservation of endangered breeds such as the Blanca Andaluza goat, has increased and some steps should be therefore taken to ensure it. The study was designed to determine the seasonal reproductive pattern of Blanca Andaluza bucks, and whether this affects the quality of their semen and its freezability over the year. Seven bucks were used and their body weight, testicular weight, plasma testosterone concentration and fresh sperm quality determined every week. The collected sperm was cryopreserved and stored; it was then thawed and the same sperm quality variables measured every fortnight. High plasma testosterone concentrations were recorded during the summer and autumn, and low concentrations were recorded during winter and spring (p<0.001). No differences were seen between seasons in terms of the percentage of bucks ejaculating, the percentage of active bucks, or ejaculate volume. However, the sperm concentration, the total number of sperm per ejaculate, and the values for most fresh sperm variables were lower during the winter period (at least p<0.05). After freezing-thawing, the quality of winter-collected sperm was better, in some respects, than that of summer-collected sperm (at least p<0.05). These results reveal that Blanca Andaluza bucks show seasonal reproductive activity in terms of their plasma testosterone concentration, but no clear change in their sexual behaviour between seasons was observed. The values of fresh sperm variables also vary over the year, reaching their lowest during winter. However, after freezing-thawing, winter-collected sperm is of overall better quality than sperm collected during the summer.
Highlights
The Blanca Andaluza breed of goat, which is native to Spain and adapted to Mediterranean environmental conditions, is endangered according to the Official Catalogue of Spanish Livestock Breeds (RD 2129/2008; BOE, 2009)
High plasma testosterone concentrations were recorded during the summer and autumn, and low concentrations were recorded during winter and spring (p
After freezing-thawing, the quality of winter-collected sperm was better, in some respects, than that of summer-collected sperm. These results reveal that Blanca Andaluza bucks show seasonal reproductive activity in terms of their plasma testosterone concentration, but no clear change in their sexual behaviour between seasons was observed
Summary
The Blanca Andaluza breed of goat, which is native to Spain and adapted to Mediterranean environmental conditions, is endangered according to the Official Catalogue of Spanish Livestock Breeds (RD 2129/2008; BOE, 2009). In addition to its use in the genetic improvement of livestock animals, semen cryopreservation is essential in the preservation of endangered genetic resources. It is not sure whether male Blanca Andaluza goats show reproductive seasonality. Understanding how this might affect semen quality and freezability over the year could throw light on how to improve the quality of cryopreserved sperm. Short days and decreasing daylength stimulate the secretion of luteinizing hormone (LH), which in turn, induces testicular growth and the release of testosterone, resulting in quantitative and qualitative improvements in semen production plus increased sexual behaviour.
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