05/30/2001 11:00PM

Hemlock could be cause of abortions


LEXINGTON, Ky. - Ongoing research by a pair of Clemson University scientists has identified another possible culprit for mare reproductive loss syndrome: the hemlock plant.

Dr. Dee Cross, a professor of animal science at Clemson, and graduate student Sam Gray have been studying the syndrome since May 9 at the request of several large central Kentucky farms. Their work has revealed a high correlation between the presence of poisonous hemlock plants and the syndrome's occurrence.

University of Kentucky officials announced on May 24 that they believed cyanide from wild black cherry trees was a likely cause of at least 1,200 early-fetal and near-term abortions in central Kentucky's mares since April 26. Now, Cross's epidemiological survey - which includes major operations in Paris and Midway, among others - suggests that there may be a closer relationship between hemlock and the abortions. But both Cross and UK have emphasized that investigations are continuing and scientists have more research to do.

Hemlock produces a group of five alkaloids, called coniine alkaloids, that are toxic when eaten. Drought and late-spring freezing may have damaged horses' preferred pasture grasses, prompting them to browse for different forage.

"Hemlock plants are very toxic," Cross said. "Their leaves and roots are especially toxic, and the plants are more toxic when they are young and immature. For some reason, maybe due to the freeze and drought, the conditions were just right to encourage horses to do some browsing as they grazed. No one knows why horses began browsing, but we have found bite marks on hemlock to show that."

Cross said he and Gray have studied farms and fields affected by the syndrome and some not affected by it, and their research to this point shows a low correlation between the syndrome and the presence of wild black cherry trees.

"But we are coming up with a very high correlation between fields and farms with problems, those with no problems, and the number of hemlock plants in fields that are grazed," he said.

Cross also said that he has found some early consistencies between hemlock poisoning and pathological findings on aborted fetuses, but he would not elaborate, citing the need for more investigation.

Hemlock typically grows to between three- and six-feet tall and has a white, umbrella-shaped seed head on a purple-tinted stalk. A member of the parsley family, it also has parsley-like leaves.

Cross said that hemlock rarely grows in pasture but is fairly common in fence rows and in tree enclosures that dot some horse pastures.

"Hemlock grows well in low-lying areas with rich, fertile soil, like that near waterways, and in tree enclosures and fence rows," Cross said. "You rarely see it right in a pasture, because it isn't a plant that survives close mowing very well."

Cross has worked with central Kentucky farms in recent years on another pasture threat, fescue toxicosis, and he said that his work so far, like Gluck's, has shown little relationship between tall fescue and the abortion syndrome.

Cross emphasized that he and Gray are still investigating hemlock's connection to the syndrome and have contacted UK's Gluck Equine Research Center and Livestock Disease Diagnostic Centers regarding their findings.

"We want other people to confirm or negate what we're finding," Cross said. "Our goal is to help the horses and the foals."

Record low in Keeneland July catalog

Keeneland's July selected yearling sale will have a record low number of horses this year, with just 164 lots in the catalog. That beats the previous low of 208 in last year's catalog.

But Keeneland spokesman Jim Williams, noting last year's record sale average of $621,015 and overall receipts of more than $80 million, said the auction house is still committed to holding the July auction despite a trend toward a smaller catalog.

The catalog numbers have declined every year since 1997, when 260 yearlings were in the book. "We're selling some of these horses as weanlings, and they're not going back through the ring again," said Williams, who cited recent Irish 2000 Guineas winner Black Minnaloushe, a $750,000 weanling bought by Demi O'Byrne, agent, as an example of an expensive, potentially July-quality horse bought young and kept for racing rather than resale.

Williams also noted that some consignors - most notably Will Farish's Lane's End Farm, formerly a mainstay of the Keeneland July auction - are choosing to sell at the company's popular September sale instead. That auction, which offers a much larger catalog over more than a week of selling, allows consignors to present horses who are slightly more mature, which especially benefits sellers with late foals who may appear small in July.

But the September sale may also slim down this year after selling 3,313 head in 2000.

"It looks like the total number of yearlings Keeneland will sell this year could be down slightly overall," Williams said. "Early indications are that we might not be selling quite as many in September."

The Keeneland July sale will be held in two consecutive evening sessions on July 16-17, starting at 7:30 p.m. Catalogs are available online at www.keeneland.com; Keeneland will mail print versions the week of June 11.