Therapeutic management of marwari mares suffering from bacterial endometritis vis-à-vis antimicrobial sensitivity

Inappropriate use of antibiotics to treat infectious endometritis in mares can lead to increased antimicrobial resistance (AMR) and, ultimately, hinder the success of achieving pregnancy. This study aims to investigate the diagnosis and treatment of infectious endometritis in sub-fertile Marwari mares. The mares with a reproductive history of either failure of conception upon repeated covering or failure to exhibit estrus were investigated through trans-rectal real-time B-mode ultrasonography for intra uterine fluid-IUF, endometrial cytology-EC and bacteriology. The 61 mares (repeat breeder-50, anoestrus-9 and silent estrus-2) with bacterial uterine infection were subjected to pre-breeding treatment which comprised of sensitive antibiotics (3 g Chloramphenicol/200mg Gentamicin/3 g Ampicillin Sulbactum diluted in 50ml normal saline, intrauterine), ecbolic (25IU i/m, Inj. Oxytocin), and anti- inflammatory drugs (500mg PO, Bol. Tolfenamic Acid, bid) for three days during estrus. The mares were naturally covered by proven stallion, and pregnancy was confirmed by transrectal ultrasound examination on Day 30 post mating. The results revealed that 62.88% of mares had bacterial uterine infections and 69 isolates, with the highest frequency of E. coli (36.23%) and Staphylococcus spp. (30.43%). The chi-square analysis revealed a significant association of uterine infection with IUF and EC. The study further identified chloramphenicol and gentamicin were the most sensitive antibiotics against the bacterial isolates. The pre-breeding therapeutic management of mares resulted in a 54.01% overall pregnancy rate (48.00, 77.78 and 100.00% in RB, anoestrus and silent estrus mares, respectively). The study’s findings indicate that bacterial infections are present not only in repeat breeder mares but also in mares experiencing anestrus and silent estrus. This finding highlights the widespread prevalence of bacterial infections among different types of sub-fertile mares, emphasizing the necessity for comprehensive management strategies to tackle this issue. This study highlights the importance of pre-breeding bacterial investigation and treatment to improve fertility and minimize rise of AMR in equine industry.