Frozen Semen Overview
Use these quick links to navigate to each section of this article.
Semen quality must be good for freezing | Main sperm defects in dogs | Which defects matter with frozen semen? | Frozen semen handling – potential points of failure | Additional resources | Additional references
Semen quality must be good for freezing.
- 150 million minimum needed
- Average for Large dogs (25-45kg) : 600-800 million sperm cells/ejaculate
- Collection impacts count- miss some, dog not aroused
- 70% forward motility minimum needed
- Average for Large dogs (25-45kg) : 600-800 million sperm cells/ejaculate
- Environment impacts motility- temperature, assess immediately or keep at proper temp
- 1-2 hrs -room temperature (20-22°C), > dilute in extender, cool slowly to 4-5° C)
- > 70% normal morphology considered normal- higher the better but always some
- >30% abnormal- Don’t freeze
- >50% abnormal- Risk of infertility
- Ejaculate male 2 days prior to analysis if hasn’t been ejaculated recently,
- >12 months old best or may have abnormalities due to sexual immaturity
Main Sperm Defects in Dogs
LOCATION
Head
Neck
Midpiece
Tail
Spermatogenesis Abnormalities
(Primary)
Macrocephalus, microcephalus, double, pointed, indented heads
Thickened, eccentric insertion
Thickened (swollen, thinned, coiled, kinked, double midpiece
Thin, double, triple tail
Maturation, ejaculation or handling
(Secondary)
Free, bent heads, swollen acrosomes, detaching acrosomes
Bent midpiece, extraneous material surrounding midpiece, proximal, mid and distal cytoplasmatic droplets
Coiled, looped, kinked, folded, detached tail.
Chart: Artificial Insemination in Dogs, Rita Payan-Carreira1, Sónia Miranda2 and Wojciech Niżański, Poland
Images from Colorado State and http://therio.vetmed.lsu.edu/sperm_abnormal_print.htm, fertilitypedia.org
Which defects matter with frozen semen?
- Proximal droplets: Don’t freeze, Maturation defect that impacts fertility
- Any defect that impairs movement, viability
- Primary Head Defects – impacts DNA. May penetrate egg but no pups result
- Not all abnormalities impact fertility – But they may impact viability of frozen semen
- You can’t see all abnormalities
Clinical and Structural Features of Sperm Head Vacuoles in Men Included in the In Vitro Fertilization Programme
Nina Fekonja,1 Jasna Štrus,1 Magda Tušek Žnidarič,1,2 Katja Knez,2 Eda Vrtacnik Bokal,3 Ivan Verdenik,3 and Irma Virant-Klun3
Frozen Semen Handling - Potential points of failure
- Collection- contaminants (blood, chemicals)
- Extender used
- Chilling procedure to prepare for freeze
- Freeze temperature and speed
- Storage – always in LN2
- Thaw temperature
Additional Resources
- Sperm Motility – Principles – Melissa Rouge, Colorado State University – http://www.vivo.colostate.edu/hbooks/pathphys/reprod/semeneval/motility.html
Additional References
- Charlesworth, D., Willis, J. The genetics of inbreeding depression. Nat Rev Genet 10, 783–796 (2009). https://doi.org/10.1038/nrg2664