March, 1956]
E.
S.
E.
HAFEZ
39
about 16 days before the first heat. Lactation in the ewe did not inhibit the expres-
sion of oestrus. Breed differences as well as individual differences were recorded for
the age at first oestrus, and the number of services per conception. This is either due
to the different inherited levels of output of the adenohypophysis among the breeds
or to the different reactions of the individuals to the environment. There is much
evidence of a general nature that the varying degrees of activity of the gland are
inherited. Genetic analysis of this character is rather difficult due to the interaction
of the different hormones and the genetic factors.
SUMMARY
In the expression of fertility there is an interaction between the components of
climate (mainly daylight and temperature), husbandry methods and the genetic make-
up of the animal. Thirty-three buffalo-cows, 22 Egyptian cows and 99 fat-tailed
sheep were tested with ochred teasers daily. Fertile services were allowed and the
conception and parturitions recorded. Rectal palpation was carried out in big
animals while all the after-births were dissected. Non-pregnant and pregnant geni-
talia of two classes of animals were examined to investigate ovulation rates and
the health of pregnancy.
In the buffalo-cow, the percentage of conceptions requiring one, two and three
services were 56, 22 and 8 respectively. The average interval to post partum oestrus
was 35 days in the buffalo-cow, 38 days in the cow and 40 days in fat-tailed ewes.
Twin ovulations were never observed in the buffalo-cows and were rare in the cows
Embryonic mortality occurred in 9 per cent of the buffalo-cows and 8 per cent of
the cows.
The breeding efficiency of the female of farm animals was raised by continuous
association with ochred fertile males. Reproduction sheets are also recommended.
The incidence of first oestrus, post partum oestrus, silent heat and reproductive
disorders (mainly foetal mortality) must be considered. Rectal palpation of
pregnant animals should be carried out at intervals to confirm healthy pregnancies.
The after birth of breeding animals as well as the genitalia of culled animals should
be examined.
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Asdell, S. A. (1952). A regional approach to problems of fertility and breeding efficiency in dairy
cattle. Proc. 2nd Int. Congr. Physiol. Path., (Copenhagen) 2, 7-16
Badreldin, A. L. (1952). Frequency of successful conception under free mating conditions in the
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