VIe CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. II

TABLE 3

Sheep and Cattle - Possible causes of subfertility
at sznchronized oestrus following
progestagen treatment

1. Causes of failure

a. Failure of fertilization J
b. Embryonic mortality

i. Non-lactating X

i1 Seiac tatine J

2. Reasons for failure of fertilization

a. Poor sperm transport and/or survival J
b. Faulty sperm-capacitation X
c. Faulty eggs X
d. Faulty tubal environment X
e. Non-synchronous oestrus and ovulation X
3. Reasons for faulty sperm transport and/or
survival
a. Cervical penetration - mucus X
b. Motility of the tract X
c. Faults in tract )
d. Faults in vagina 2
4. Reasons for faults in the tract
a. Physical faults early after parturition v
b. Endocrine status
i. Progesterone-oestrogen interaction N
ii. Other hormones ?
5. Reasons for embryonic mortality
a. Faulty eggs X
b. Late fertilization {
cildEaulitse invtract 2

1353