Vie CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. I

THE EFFECTS ON EQUINE REPRODUCTIVE
FUNCTION OF UTERINE INFUSION OF SALINE

G.H. ARTHUR
Department of Surgery and Obstetrics,
Royal Veterinary College, London, England.

In veterinary practice non-pregnant mares
which do not show heat may be cases of true
anoestrus with cyclical inactivity, or they may
be cycling mares which do not manifest heat -
so-called suboestrus, or "silent heat", cases.

When a veterinary surgeon is asked to examine and
treat a mare which does not show heat it is im-
possible for him to state on the basis of a single
gynaecological examination of the ovaries and
cervix whether the mare is anoestrous or dioestrous.
Only the suboestrous mares that happen to be in
silent heat at the time of the examination can be
identified; all the remainder tend to be put into
the same category of "anoestrus!'. The present in-
vestigation was designed to clarify the responses
at different times of the year of both anoestrous
and dioestrous mares to uterine infusion of saline
and, in particular, to find out whether ovulation
accompanied the heats which might be induced in
both these phases of reproduction.

MATERIALS AND METHODS. Five of the mares used
were of the Welsh Mountain breed and three were
Thoroughbreds; their ages ranged from 5 to 10
years. The mares were in good bodily condition.
They wintered out-of-doors when hay was fed but
during Spring and Summer they were housed during
the day and turned out at night. The investi-
gation extended from February 1967 to May 1968.
Two of the mares were treated at approximately
monthly intervals throughout the experiment. The
remaining 6 mares were treated during the breeding
seasons of 1967 and 1968 and of these, 3 had
foaled during 1967 and 3 were barren that year.
The reproductive status of each mare at the time
of treatment was known from previous gynaecological
examinations.

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