It
may be due to fertilization failure or atypical fertilization.
Fertilization failure may be due to death of sperm, death of egg
before fertilization, structural and functional abnormalities in egg
or sperm and physical barriers which prevent the gamete transport
e.g. closure of fallopian tube. It may also be due to ovulatory
failure as in case of COD.
Abnormalities of Egg:
Several morphological and functional abnormalities of eggs as
Abnormalities of Sperms:
-
Structural defect of DNA
-
Sperm aging - aged sperm have changes in acrosome
-
Life of sperm or egg and life of fertilization - fertilizable
life is lost much earlier as compared to life of sperm. With
aging ability to fertilize is lost and leakage of intracellular
enzymes and constituents like cyclic ANP. Life of sperm is 24
hours while life of ovum is 12-18 hours.
Structural and Functional Causes of Fertilization Failure:
Cause |
Abnormality |
Species |
Mechanism |
|
Structural Abnormalities |
Congenital |
Mesonephric cyst , uterus unicornuous or double cervix |
Swine Cattle |
Sperm transportation is affected |
Acquired |
Tubal adhesions, hydrosalpinx, pyosalpinx
|
All species |
Transportation mechanism is affected |
|
Functional Abnormalities |
Hormonal |
COD, defective secretions from uterus
|
All species |
ovulation and gamete transport is affected |
Managemental |
Delayed insemination, wrong time insemination, errors in
estrous detection |
Bovine |
Death of sperm or ovum, fertilization does not occur |
|
|