Assessment of an iPad-based sperm motility analyzer for determination of canine sperm motility.

The objective of this study was to evaluate the repeatability and accuracy of canine sperm motility (total and progressive) assessment with a tablet-based Canine iSperm instrument compared to computer-assisted sperm analysis (CASA). The experiment used fresh and frozen/thawed canine semen samples for comparisons of semen analysis parameters (concentration, total motility, and progressive motility) between a CASA system, iSperm, and NucleoCounter SP-100 (concentration) instruments. Spearman's Rho correlational analysis was used to identify significant associations between motility assessment methods. Significant positive correlations were found between CASA assessment and iSperm for both progressive and total motility measurements. We also determined the coefficient of variation (CV) for repeatability of sample analysis for iSperm and CASA for fresh sperm, wherein each sample was assessed 10 times on both devices. For fresh and frozen-thawed samples, concentration assessment by iSperm showed high variability (CV= 19.9 ± 1.5%). For iSperm assessment of total and progressive motility, the CVs were 6.3 ± 0.5% and 10.7 ± 0.8%, respectively. The results indicate that the iSperm application offers an accurate and alternative measurement of motility to traditional CASA analysis, though caution should be taken when assessing concentration due to the high CV observed in this study.

Effects from aging on semen quality of fresh and cryopreserved semen in Labrador Retrievers.

Characteristics of frozen sperm associated with fertility and aging have not been fully determined in dogs. The aim of this study was to determine the relationship between fresh and post-thaw sperm quality, age, among the factors of motility, viability, morphology and oxidative stress in a group of fertile stud dogs with extensive breeding records and in dogs with reported subfertility problems. Sperm parameters from 39 fertile dogs were measured in fresh semen and frozen thawed semen. Additionally, frozen semen from 9 subfertile dogs was thawed and analyzed. Subfertile dogs were defined by referring veterinarians solely on the basis of owner history; breeding records were not available to this study. Evaluation included total motility (TM) and progressive motility (PM), average path velocity (VAP), viability, morphology and presence of sperm reactive oxygen species (ROS). Fertile males' ages ranged from 1 to 10 years, subfertile males' ages ranged from 4 to 14 years. All dogs were assigned to age groups according to age as young (1-3 years) middle (4-6 years) and senior (>7 years). The effect of sperm state (fresh vs. frozen-thawed), age, and fertility history (fertile vs. subfertile) on the measured endpoints were determined using a mixed effects model. TM showed a negative correlation with age in the frozen-thawed semen. Additionally, TM in fresh semen was higher in all age groups compared to post thaw semen (P < 0.05). PM was higher in all age dogs of fresh semen compared to frozen-thawed semen (P < 0.05). As such, TM and PM in post thaw semen statistically decreased compared to fresh semen regardless of age of stud male (P < 0.05). Differences in VAP were only observed between young and senior age groups in fresh semen (P < 0.05) while young and middle age dogs from fresh semen were different in all age groups for frozen-thawed semen (P < 0.05). ROS was higher in the young frozen-thawed semen compared to the young fresh semen (P < 0.05). When comparing TM, PM and VAP of fertile vs. subfertile dogs, middle aged fertile dogs are different from middle aged and senior subfertile dogs (P < 0.05). No differences were found in measures of ROS between fertile and subfertile. For sperm viability and morphology, differences were observed between all age groups of fertile dogs in comparison to all ages of subfertile dogs (P < 0.05). Sperm motility appeared to be the most affected parameter by freezing damage than any other parameter measured in this study, while we were not able to determine a significant association between ROS production and fertility status.

Semen evaluation and fertility assessment in a purebred dog breeding facility.

Semen quality in dogs has not been assessed in a longitudinal study that includes endpoints of female fertility and pregnancy. Although use of artificial insemination with chilled semen is increasingly used in canine reproduction, the resultant level of predictability and odds of fertile matings for dogs is still not fully understood. This research provides, for the first time, comprehensive semen evaluation in a large population of dogs in which fertility has been tracked. Duplicate ejaculates were obtained from 39 Labrador retriever males of the Guide Dogs for the Blind (San Rafael, CA, USA) breeding program. Sperm endpoints were determined in fresh semen and extended chilled semen at 48 hour after collection. Evaluation included total and progressive motility, average path velocity, morphology, membrane lipid peroxidation, presence of sperm reactive oxygen species, sperm chromatin structure, and mitochondrial DNA copy number. Male age ranged from 1 to 10 years and were grouped as young (Y; 1-3 years, n = 21), middle aged (M; 4-6 years, n = 13), and senior (S; 7 years or greater, n = 5) for analysis. The effects of age and sperm state (fresh vs. chilled) on the above sperm endpoints were determined using a linear mixed effects model. Semen endpoint values for all parameters were established for this group of fertile males. Progressive motility was only lower in the senior male chilled samples compared to all other groups, fresh and chilled (P < 0.05). Velocity decreased with increasing age and was lower overall in chilled samples (P < 0.05). Percent morphologically normal sperm was lower in senior dogs compared with the other age groups (P < 0.05). The presence of reactive oxygen species was lower in chilled samples compared with fresh (P < 0.05). For sperm chromatin structure, the senior-aged group had a higher %COMPαt than the middle-aged group (P < 0.05). Bayesian analysis determined that no differences were seen in total motility, membrane lipid peroxidation, and mitochondrial DNA copy number, with regard to conception rate or average litter size between age groups or between fresh and chilled samples. We observed no effects from semen quality on fertility or fecundity regardless of age, despite the differences found in semen quality. The use of advanced laboratory tests to evaluate sperm parameters beyond the standard motility, morphology, and concentration will open investigation to more specific and sensitive fertility tests in canine reproduction.