Vle CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. Il

She-Mule MUL/I

 

Observiiis nun;be gz;?.?:;e?f Control of ovaries
period mo(:mfhs ’ ] number of
ovulation| atresia folliclos
false atresia)

n % n %

| 19 22 21 3761l 8| 39 - -

I 69 15 6 4 | 66 251834 - -
11 27, 73 3 1 34 21566 - - I
________________________________________________ et |

115 40 30 18 60 12 40 - -

On November14, 1965 she came in heat spontaneously after a long
anoestrus. A follicle grew on the left ovary which reached 6 cm in dia-
m eter on the fourth day, and disappeared the next day (ovulation).

Two days later the mule was slaughtered, and treated as was mule
1. From the left tube three egg cells were flushed. One was found to be
about 168 p in diameter with a comparatively thick zona of 20
(Photo 2).

The second was elongated, 163 x 144 p , with a zona 12.5y
thick (Photo 3), and the third was about 152p in diameter with a damaged
zona pellucida. The zona was 12,5 p  thick (Photo 4).

It is possible to say that in older she-mules the activity of the ov-
aries is less and less regular than in animals 5-8 years old. In spite of a
long period of anoestrus, both the 15-year old mules reacted to prolonged
daily light periods. This shows that light may play arole in inducing
fertility in the mules where reported cases of progeny born of she-mules
w ere concentrated in the tropical and subtropical zones.

We hope the finding of egg cells in she-mules will stimulate further
research in countries where suitable material is available for this purpose.

The authors express sincere thanks to Dr, S. JAROSZ for his help
in flushing and examining the egg cells.

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