ABSTRACTS
331
once cerceriæ resembling those of Fasciola from Physopsis africana. The author found
that the miracidia of Fasciola escapes from the eggs in water in a test-tube on the 21st
day, this finding is in contravention to the observations of Mönnig who observed that in
Fasciola the miracidia emerge out of the egg on the 14th day. The author has observed
that it is not necessary for the eggs to pass through the gut in order to attain maturity.
They can do so even in bile-ducts. The author is of the opinion that molluscs are not
infected simply by devouring Fasciola ova which have not had the opportunity of reaching
maturity in water. The author concludes with the remarks that Lymnæa natalensis is
only an occasional carrier of Fasciola disease in S. Africa and that a search should be made
for another intermediate host which may not necessarily be a fresh-water mollusc.
[G.D. B.]
Mouldy hay a cause of broken wind in horses and abortion in cows and
mares. E. MORGAN (1940). Vet. J. 96, 51-53
I N the experience of the author, extending to thirty years in Cardiganshire (Venezuela)
the occurrence of broken wind in horses is rare as compared with that in former
years. The lower incidence at present is attributed to the better system of storing hay
in up-to-date buildings. Previously farmers used to store in badly ventilated mud wall
buildings in which the hay bordering on the wall was covered with grey coloured mould.
Feeding on mouldy hay resulted in larger number of cases of broken wind. The
opinion of several farmers in the locality strongly supported this view.
The author states of having observed numerous cases of abortion in mares and
cows fed on mouldy hay. He refers to literature on the subject and points out the
difference in the clinical manifestation as noticed by him.
He also observes that the knowledge of the fungus on hay is meagre and briefly
reviews some of the diseases in animals caused by moulds or fungi. [V. R. G.]
Fertility in farm animals. A. WALTON, J. EDWARDS and J. HAMOND. (1940).
J. Roy. Agric. Soc. Eng. 100, Pt. III, 1-12.
T HE causes of infertility may be physiological or pathological. Physiological
causes may be due to inherent functional or genetical or to environmental factors.
Genetical analysis is not possible at present owing to lack of exact methods of measuring
fertility. The main physiological factors common to all animals are : fertility in the
female, fertility in the male, and the fertility of mating. The lowering of fertility from
pathological causes is either direct, due to invasion of the reproductive organs by special
micro-organisms, or indirectly due to debilitating diseases.
The (primary) fertility of the female or its fecundity depends on the egg-producing
capacity of the ovaries. Ovarian activity has two phases which alternate, viz., oestrum,
the " heat " period, when the eggs are produced, and dioeslrum, when the corpus luteum
is active. Mating rarely occurs in dioestrum, and if so, is not fertile. A state of total
inactivity of the reproductive system, anoestrum, can also occur. Fecundity is improved
by good nutritional conditions. Secondary fertility, or number of young born, depends
on the successful maintenance of the embryo during pregnancy, and foetal atrophy is
due to many factors, genetic, physiological and nutritional. Male fertility depends upon
the intensity of sperm production in the testis, which is continuous during sexual maturity.
Nutritional factors slightly affect this intensity whilst exposure of the scrotum to high
temperatures will cause spermatogensis to cease. The sperm ripens to maximum activity
in the epididymis. The success of mating depends on the coordination of the many
different processes and normal functioning of both male and female reproductive organs,
and the reproductive act culminates in the entry of one spermatozoon into the ovum.
The chances of fertilization depend on the time interval between mating and ovulation,
the length of time the ovum remains fertilizable in the female tract, the number of sper-
matozoa which reach the Fallopian tubes and the time taken to make the ascent, and the
length of time the spermatozoa can remain in the Fallopian tubes and still be able to
fertilize the ovum.
Physiological infertility in mares is common ; 40 per cent of Heavy and 33 per cent
of Thoroughbreds fail to produce foals after service. This infertility is due to inapprop-
riate time of mating during heat, irregularities of the oestrous cycle and using a stallion