Search

Germplasm banking is a fundamental tool for the preservation of autochthonous breeds. Semen cryopreservation is effective for this task, but protocols are adapted to commercial species, and post‐thawing sperm quality could be sensitive to environmental cues. We compared the post‐thawing sperm quality in doses from the CBA‐SERIDA bank in northern Spain for the Asturiana de la Montaña (AM) and Asturiana de los Valles (AV) autochthonous cattle breeds. Doses from 23 AM and 16 AV bulls (ejaculates from at least three different seasons) were assessed for motility (computer‐assisted sperm analysis), physiology and chromatin status (flow cytometry) after thawing and after 5 h at 38°C. Data were analysed using linear mixed‐effects and cosinor models for seasonal and breed effects and by correlations with the association of sperm quality with temperature‐humidity index (THI), considering the interval of spermatogenesis plus maturation. The breed affected sperm quality, with higher motility for AV and higher apoptotic ratio, mitochondrial activity, reactive oxygen species, DNA fragmentation and chromatin immaturity for AM. However, seasonality effects were minimal, and THI was not associated with sperm quality. In summary, the season seems to be a minor factor in the post‐thawing quality of the AM and AV autochthonous breeds, well‐adapted to their local environment. [ABSTRACT FROM AUTHOR]

Semen banking is critical to preserving rare and autochthonous breeds. However, protocols can change with time, leaving heterogeneous semen batches. The objective of this study was to assess differences in sperm quality and field fertility. We report differences between batches frozen with the Biociphos and BIOXCell extenders in the Asturiana de la Montaña cryobank (autochthonous and endangered breed, Northern Spain). Doses from 48 bulls were analysed by CASA and flow cytometry. The 85‐days non‐return rates from AI records were used to assess the fertility of 23,853 AI. BIOXCell showed higher quality post‐thawing. Differences increased after a 5‐hr incubation at 37°C, and Biociphos yielded doses with lower resilience. Field fertility did not differ between extenders (Biociphos: 57.4% ± 1.2; BIOXCell: 56.6% ± 3.0), possibly because of AI protocols compensating for differences in quality. However, this needs to be confirmed by controlled intervention studies. In conclusion, batches frozen with Biociphos may require specific strategies for compensating for the lower sperm quality. Regular surveys and evaluation of cryobank procedures may be useful to characterizing stored batches and defining strategies to guaranteeing success in their future use. [ABSTRACT FROM AUTHOR]