Forage-Animal Production Research

Reieareh Proposals to Identity the Causes and Prevention of Mare Reproducdve LoSS Syndrome: . Mare Reproductive Loss Syndrome (MRLS) had u severe impact on horse breeding in central Kentucky in April and May of 2001. Clin.ical signs of the disease included early and late::fetal losses, birth, of weak foals and a number of cases of pericarditis and unilateraJ uveitis. Environmental toxins are the primary SUspectl;~with opportunistic infectious agents playing a secondary role. Epidcmiologicalstudies suggest strong associations with the presence of Black Cherry trees and Eastern Tent Caterpillars (ETC). Contingency recommendations and monitoring programs are being put in place to reduce the risk of MRLS in 2002. To complement the monitoring program and addre~sidenlHicatjun of tbe cause(s) of MRJ~. the University ofKentuoky, CoUegeof Agriculture has devoloped a group often targeted research proposals. On an accelerated basis, scientists within the College of Agriculture will investigat~the efficacy and safety of insecticides recommended to eliminate ETC. , The ETC connection will be investigated by evaluating the toxicity of caterpillars for pregnant mares. AdditionallYt the rote of ETC excreta (ftass) will be studied by exposing mares to frass. University ofKontucky scientists will also survey the symbionts and paraSites of ETC, with the goal of identifying ETC- associated microorganisms that may contribute to MRLS. Preliminary work on the role of estrogenic factors in MRLS have shown ETC to contain anti-estrogenic activity; ~eriments have been designed to investig~t~the role of these substances in MRLS. The role of mycotoxins growing on pastures and/or ETC frass will also be explored. University of Kentucky and collaborating scientists will identify fungi ftom selected pastures or frass, grow tbe fungi, recover the mycotoxins and investigate their role in the etiology ofMRLS. The ergot and laline alkaloids are well-established causes of fesc'ue toxicosis in horses. University of Kentucky soientists will study their absorption in the equine intestint\ltract, with the goat of establishing their possible role in MRLS. Black Cherry trees contain cyanogenic glycosides, whose' toxic potentia1 1~ highest in early spring. Scientists will establish normal cyanide concentrations in horses at pasture, and investigate the role of cyanogens on fctal survivability. Related proposals will focus on the effects of cyanogcn.son cellular defense mechanisms. Together these projects will define the role of cyanogens and 'opportunistic bacterial pathogens in MRLS.