Page 443 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

418 CHAPTER 2

VetBooks.ir or cycling. The stage of the cycle and the time since (formalin or Bouin’s solution) and tissue sections are
examined for:
parturition should also be kept in mind when inter-
preting endometrial cytology. For example, the
presence of polymorphonuclear cells <5 days post • Inflammation or endometritis.
partum is part of the normal cytological picture at • Periglandular fibrosis.
this time. • Cystic glandular distension and lymphatic stasis
(Fig. 2.19).
Endometrial biopsy • Classification is based on the severity and
This procedure is useful for the diagnosis of endo- distribution of the lesions and is associated with
metrial pathology and prognosis for future fertility, the expected ability of the mare to conceive and
but is not necessary in every mare. Samples should carry a foal to term:
be sent to an equine pathologist experienced in the • Category I: slight and/or widely scattered
interpretation of endometrial biopsies. It is useful for pathology; 80–90%.
an aged mare, mares with a history of pregnancy loss • Category IIA: endometrial changes that
or chronic endometritis and in mares being assessed reduce breeding efficiency but are moderate
as potential embryo-transfer recipients. Histological or reversible. Inflammation is detected;
assessment can detect varying degrees of inflamma- 50–80%.
tion and fibrosis and evaluate glandular changes. It • Category IIB: as for IIA but fibrosis is also
is a well-established and safe procedure. The biopsy present; 30–50%.
is collected using a custom-made 70-cm alligator • Category III: irreversible and severe changes
biopsy punch with a basket size of 20 × 4 × 3 mm. of fibrosis, cellular infiltration and lymphatic
A single biopsy taken from the base of one horn is stasis; 10%.
generally considered to be representative of the
entire uterus. Samples can be obtained at any time Fibreoptic examination of the uterus
in the oestrous cycle, but the pathologist should be Hysteroscopy or uteroscopy provides visual infor-
informed of the stage of the cycle and other relevant mation on the endometrium and is carried out using
findings. The collected tissue is placed into fixative a suitable fibreoptic or video endoscope (Fig. 2.20).

2.19 2.20

Fig. 2.19 Histopathology of an endometrial biopsy Fig. 2.20 Examination of a mare by video
specimen from a Thoroughbred mare showing an hysteroscopy. (Photo courtesy Tracey Chenier)
endometrial gland nest, as is often seen in older mares
with chronic endometrial pathology.