Research articleEffect of method and clinician on stallion sperm morphology evaluation
Introduction
Sperm morphology evaluation is an essential component of semen analysis and provides the clinician invaluable information for assessing the breeding soundness of a stallion and the potential fertility of individual semen samples. Although the Society for Theriogenology (SFT) recommends the use of wet-mount semen preparations and phase-contrast or differential interference contrast microscopy for evaluation of sperm morphology in stallions [1], comparisons among different methods have apparently not been reported. Eosin/nigrosin is a stain recommended by the SFT for evaluation of bull sperm morphology [2] and is widely used, mainly because of its ease of use. In contrast, the World Health Organization (WHO) recommends the use of Papanicolaou stain for evaluation of human sperm morphology [3].
Several studies from laboratories evaluating human sperm described variations in sperm morphology results that could be attributed to technician differences [4], [5], [6], [7]. One of the main reasons for this variation was likely the lack of quality control measures, including appropriate training, continuing education, and proficiency testing. Although no similar studies have been reported, the same issues are expected to affect sperm morphology assessment in veterinary andrology laboratories.
The objectives of the present study were to determine the effect of method and clinician on stallion sperm morphology evaluation.
Section snippets
Preparation of semen samples
Sixty semen samples from 34 stallions (1 to 4 samples per stallion) were evaluated in this study. Stallions represented 12 breeds, ranged from 3 to 23 y of age, and were part of the population presented to the New Bolton Center of the University of Pennsylvania School of Veterinary Medicine for breeding soundness evaluation, fertility problems, breeding management, or semen processing for shipment or freezing. As such, this diverse population represented a wide range of fertility, from normal
Results
The proportion of sperm with “other sperm defects” (duplicate heads and tails, and teratoids) was very low (< 0.5%) and was excluded from the analysis. There were method effects (P < 0.05) on the proportions of all sperm morphology categories (Table 1). The proportion of normal sperm was greater (P < 0.05) and the proportions of acrosome, head, midpiece, and principal piece defects, and cytoplasmic droplets were less (P < 0.05) in Papanicolaou-stained samples when compared to wet-mount
Discussion
Differences in sperm morphology results among different evaluation methods can only be attributed to introduction of artifacts, poor resolution/definition of sperm structures, and unfamiliarity of the evaluator with the distinctive appearance of sperm processed by a particular method. Studies comparing methods of sperm morphology evaluation have either used only the proportion of normal sperm, which by itself is not a reliable endpoint from which to draw conclusions, or have made little effort
References (22)
Evaluation of stallion semen
Vet Clin North Am Equine Pract
(1992)Evaluation of stallion sperm morphology
Clinical Techniques in Equine Practice
(2007)- et al.
Sperm morphology of beef bulls evaluated by two different methods
Anim Reprod Sci
(2010) Evaluation of potential soundness of the bull
- et al.
Monitoring technologist reading skills in a sperm morphology quality control program
Fertil Steril
(2003) - et al.
Society for Theriogenology manual for clinical fertility evaluation of the stallion
(1983) - et al.
A new bull breeding soundness evaluation form
(1992) World Health Organization laboratory manual for the examination and processing of human semen
WHO Press
(2010)- et al.
Multicenter study on reproducibility of sperm morphology assessments
Arch Androl
(1998) - et al.
Results of the American Association of Bioanalysts national proficiency testing programme in andrology
Hum Reprod
(2000)
Inter-individual variability in the morphological assessment of human sperm: effect of the level of experience and the use of standard methods
Hum Reprod
Cited by (51)
Post-thawing Sperm Quality in Chilean Purebred Stallions: Effect of Age and Seasonality
2020, Journal of Equine Veterinary ScienceHeterosis for morphometric characteristics of sperm cells from Duroc x Pietrain crossbred boars
2019, Animal Reproduction ScienceCitation Excerpt :In research conducted with humans (Maree et al., 2010) and animal semen (Łącka et al., 2016; Andraszek et al., 2018), staining method was determined to effect the measurements for sperm variables (e.g., head shape), therefore staining methods can affect results when there are sperm cell measurements (Maree et al., 2010). The staining technique used can contribute to variability in sperm measurement outcomes as a result of the action of the chemical reagents used for staining (Brito et al., 2011; Czubaszek et al., 2019). Staining reagents can induce shrinkage or swelling of the sperm heads (Banaszewska et al., 2015).
- 1
Present address: ABS Global, 1525 River Rd, DeForest, WI 53532, USA.