Low-dose insemination--why, when and how.
The typical dose for insemination into the uterine body of the mare is > 300 x 10(6) progressively motile spermatozoa (PMS) and an insemination dose of > 200 x 10(6) PMS is recommended for frozen-thawed semen. Low-dose insemination techniques allow for a drastic reduction in the numbers of spermatozoa required to achieve pregnancy. Acceptable pregnancy rates can be achieved with doses ranging from 1 to 25 x 10(6) PMS in volumes ranging from 20 to 1000 microL. Two techniques have been described: hysteroscopic insemination and transrectally guided deep horn insemination using a pipette. Similar pregnancy rates can be attained by either method when 5 x 10(6) PMS are used. Hysteroscopic insemination may provide an advantage when the dose is 1-3 x 10(6) PMS. These techniques have the potential to make more efficient use of frozen-thawed or sex-sorted semen from certain stallions. The use of low-dose insemination to improve fertility of infertile stallions warrants further investigation.
Lyle
S K
SK
Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA. slyle@lsu.edu
Ferrer
M S
MS
D000818:Animals; D015925:Cryopreservation / Q000379:methods / Q000662:veterinary; D004716:Endometritis / Q000209:etiology / Q000662:veterinary; D005260:Female; D006734:Horse Diseases / Q000209:etiology; D006736:Horses; D015907:Hysteroscopy / Q000009:adverse effects / Q000662:veterinary; D007315:Insemination, Artificial / Q000009:adverse effects / Q000379:methods / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D012662:Semen Preservation / Q000379:methods / Q000662:veterinary; D013076:Sperm Count; D013081:Sperm Motility; D013997:Time Factors