College of Agriculture
Veterinary Science	Mare Reproductive Loss Syndrome Index Page
Keeneland Session

Mare Reproductive Loss Syndrome

Sample Testing Summary
Results and Conclusions
May 24, 2001

Dr. Jimmy C. Henning
Extension Professor
University of Kentucky College of Agriculture
Department of Agronomy

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• White clovers were not a source of cyanide due to stress and frost on problem farms.

• Ergot-type alkaloids from bluegrass or orchardgrass were not the cause of EFL or LTA.

• Tall fescue alkaloids were associated with all LTA fields observed (although this was a small number). There is possible involvement with endophyte infected tall fescue with the LTA problems. However, the symptoms of LTA observed in 2001 are unlike any known case of fescue toxicosis.

• It is unlikely that pasture mycotoxins were involved in EFL or LTA. This conclusion is based on HPLC results from the Trilogy Laboratory in Missouri. However, testing is ongoing to fully test the early samples that tested positive for Fusarium mycotoxins using the ELISA based assays.

• No Kentucky hay sample (all baled before the rain on May 6) tested positive for Fusarium mycotoxins. It is therefore highly unlikely that properly cured hay from first or subsequent cuttings in Kentucky will cause any mycotoxin related problems in horses.

• Because of the possible presence of eastern tent caterpillars in first cuttings of hay, producers should cull any hay made from fields that had significant numbers of wild cherry trees in the proximity.

• There is an extremely close association between the presence of wild cherry trees, the presence of the eastern tent caterpillar in very high numbers, and both EFL and LTA. Therefore, this wild cherry/ETC complex has to be considered a leading suspect in the cause of the MRLS in 2001. This conclusion is strengthened by the finding that previous outbreaks of EFL (1979-1981) were also correlated with high numbers of eastern tent caterpillars.