NOVEMBER 2022
609
have a collection bottle attached to its extremity. Before the beginning of the semen collection, a tiny puncture in the plastic liner and at the level of the rigid artificial vagina case was made to allow air outflow during the collection. For all the collections, a mare in oestrus was used to tease
the stallions, as mentioned above. Once the penis was exposed, the veterinarians on site washed the penis and directed the stallion towards the phantom. While mounting the phantom, the stallion’s penis was deflected and inserted into the adapted artificial vagina. The personnel collecting semen were responsible for holding the artificial vagina and the base of penis simultaneously, whereas two assistants were responsible for clamping the plastic liner of the adapted artificial vagina with a forceps, as described by Oliveira et al. (2020) (Fig 1). This separation method allows the collection of three
different ejaculate fractions, defined as follows (Oliveira et al., 2020): fraction A (FA) = first and the second jets, fraction B (FB) = third and fourth jets and fraction C (FC) = fifth and following jets (Fig 2).
Pathologies in bulbourethral glands and prostate
The fraction A of the equine ejaculate is composed of fluids from the bulbourethral and prostate glands (Varner et al., 1987). Therefore, in cases of bulbourethritis and prostatitis, the pre-seminal fluid may be altered (McKinnon, 2013), containing purulent or bloody characteristics. Through the use
of the fractionated semen collection, it may be possible to find the variations in colour and aspect of the pre-seminal fluid. The healthy aspect of the pre-seminal fluid is transparent
and alterations in this expected feature may suggest a pathology. The variations in colour and aspect previously cited are depicted in Fig 3. The infections in the bulbourethral glans and prostate of stallions are rare (Varner and Schumacher, 2011).
Orchitis, epididymitis and ampullitis
The fraction B of the equine ejaculate is the sperm-rich fraction, which is composed mainly of the secretions from the testicles, epididymis and ampullae, with a minimal contribution from the other accessory sex glands (Oliveira et al., 2020; Varner & Schlafer, 2015). The high sperm concentration present in this fraction is responsible for conferring the whitish/milky colour to the ejaculate. The presence of high counts of PMNs in the sperm-rich
FC
fraction of the ejaculate is suggestive of orchitis, epididymitis or ampullitis. Because fraction B of the ejaculate has secretions that may originate from different anatomical structures, other complementary examinations (e.g. ultrasound) are necessary for a more specific diagnosis (McKinnon, 2013; Varner et al., 2000). In Fig 4, we depicted an ejaculate with no alterations in the volume but the
FB
FA
FC FB Pre a) Fig 2: Fractionated semen collection of the ejaculate of stallions
without pathological alterations: Pre: pre-sperm; FA, Fraction A, first and second jets of semen; FB, Fraction B, third and fourth jets of semen; FC, Fraction C, ≥fifth semen jets, as described by Oliveira et al. (2020).
Fig 3: (a) Conventional semen collection ejaculated with haemospermia. (b) Fractionated semen collection that may be found in stallion’s diagnosed with bulbourethritis or prostatitis, with evident alteration in the pre-sperm fluid (Video S2).
b) FA
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