COUNTYWIDE : Antiserum Working on 3 Sick Horses

An experimental antiserum given to three horses suffering an illness that has killed 18 horses in Southern California appears to be working, officials said Monday.

Officials also were encouraged that no new cases of the illness surfaced over the weekend at the Orange County Fairgrounds Equestrian Center, where the sickness was discovered on Oct. 28.

Nine horses have died in Orange County, and botulism has been blamed. Officials believe that the toxin was in hay cubes manufactured in Utah and shipped late last month to at least 60 stables from Ventura to San Diego.

State officials have issued a recall of more than 850 tons of the cubes produced and distributed by Paramount Cubing, a Los Angeles County firm that denies that its product led to the deaths of any horses. The recall should be complete by the end of this week, said Stanley Buscombe, chief of feed and fertilizer for the state Department of Food and Agriculture.

Operators of the equestrian center, where 260 horses are boarded, stopped using the hay cubes last Monday, switching to loosely baled alfalfa. The illness has a five- to seven-day incubation period, thus officials are optimistic that no more horses will be stricken.

The conditions of three horses apparently have stabilized, possibly the result of the antiserum used to treat them since late last week.

Elsewhere in Southern California, several other horses became ill over the weekend, but none has died. The illness strikes the equine’s nervous system, apparently “short-circuiting” their nerve endings, causing their legs to quiver uncontrollably.