Comparative study utilizing different post-breeding treatment regimens in cyclic Arabian mares

Abstract

Background and Aim: Post-breeding treatment is the most common practice in the reproductive management of mares. Oxytocin, uterine lavage, and intrauterine (I/U) antibiotic are usually used as prophylactic therapy. This study aimed to determine the most efficient prophylactic treatment regimen among six treatment protocols applied during natural breeding of cyclic Arabian mares. Materials and Methods: The current study was conducted on cyclic Arabian mares that were subdivided into three age categories (n=968): Category I (5-10 years, n=380), Category II (11-15 years, n=361), and Category III (≥16 years, n=227). Six prophylactic treatments were applied after 4 h of breeding. According to the treatment regimen, treated mares (n=483) were divided into six treatment groups: A (n=80), treated with I/U antibiotic (1 g gentamicin); B (n=81), I/U lavage (normal saline 500 mL); C (n=83), intramuscular (I/M) oxytocin (10 IU); D (n=82), I/U antibiotic and I/M oxytocin; E (n=78), I/U lavage and I/M oxytocin; and F (n=79), I/U lavage with I/U antibiotic and I/M oxytocin. Non-treated mares were classified as controls (n=485). Ultrasonography was performed to monitor pregnant mares 30 and 60 days after mating, and mares were followed until foaling. Results: Pregnancy and foaling results reveals that in age Category I, treatment with oxytocin alone or oxytocin with I/U lavage showed the highest pregnancy and foaling rates (p<0.01). In age Category II, the highest pregnancy and foaling rates were observed in lavage treatment (p<0.01), whereas, in age Category III, the good pregnancy and foaling rates were monitored in treatment with oxytocin and I/U lavage (p<0.01). Conclusion: Treatment with systemic I/M oxytocin is ideal in early age group mares (5-10 years of age). However, irrespective of the age categories, all mares exhibited high pregnancy and foaling rates after treatment with systemic I/M oxytocin and I/U lavage with normal saline (0.9%) 4 h post-breeding.

Unexplained reproductive failure in a Thoroughbred mare with a uterine infection by Arcanobacterium hippocoleae

“…In the present case, the clinician chose an antimicrobial treatment followed by an antimicrobial prophylactic infusion. Previous studies have demonstrated an increase in pregnancy rates in mares using post-breeding treatment with intrauterine antibiotic infusion (Karam et al, 2021). In opposition, some authors have demonstrated that post-breeding endometritis is a physiological response during the first 48 h after cover and does not necessarily require medical treatment (Karam et al, 2021;Maischberger et al, 2008).…”

“…Previous studies have demonstrated an increase in pregnancy rates in mares using post-breeding treatment with intrauterine antibiotic infusion (Karam et al, 2021). In opposition, some authors have demonstrated that post-breeding endometritis is a physiological response during the first 48 h after cover and does not necessarily require medical treatment (Karam et al, 2021;Maischberger et al, 2008). This endometrial inflammation is caused by components directly introduced into the uterus of mare, including semen, bacteria and other debris.…”

“…Past 48 h after mating, a persistent post‐breeding endometritis (PPBEM) is confirmed through complementary examinations, as endometrial cytology, bacterial culture and ultrasonography. Antibiotic treatment is strictly recommended after bacteria involvement confirmation and antimicrobial susceptibility test performance (Karam et al, 2021; Maischberger et al, 2008). Additionally, the prophylactic antimicrobial infusion practice may contribute to the increase of bacterial resistance.…”

Clinical Aspects of Bacterial Distribution and Antibiotic Resistance in the Reproductive System of Equids

“…Uterine lavage by using normal saline after mating is often employed in stud farms because of its ability to increase the tone of uterine muscular layer and its effect in clearing microorganisms, spermatozoa, inflammatory cells and debris from the uterine lumen, as these have been found to contribute to early embryonic death in mares [ 121 ]. Use of lactated Ringer’s solution has also been advocated [ 122 ], whilst the use of iodine povidone solution has not become widely applied, as it might cause local inflammation [ 123 ] and reduced expression of endometrial progesterone receptors, hindering fertility [ 124 ].…”

“…A potential benefit of oxytocin administration after mating or artificial insemination refers to the increase of contractions of uterine muscles to eliminate excessive spermatozoa, as well as bacteria that might have invaded into the uterus at that time. Oxytocin is used because of its contractile action on the myometrium that would accelerate uterine involution and mucosal degeneration [ 121 ]. However, at later stages during gestation, the increased uterine contractility may cause adverse effects to the foetus borne, hence caution must be applied when administering to mares the correct oxytocin dose according to specific situations [ 172 ].…”