Abstract: Eastern equine encephalitis virus (EEE) was isolated from the salt marsh mosquito, Aedes sollicitans, collected from coastal areas of New Jersey on 3 occasions during the late summer and fall of 1982. The isolations were made at a time when local Culiseta melanura were either undergoing a population increase or exhibiting high levels of EEE virus. Although no human cases were reported during the epizootic period, the data lend support to the hypothesis that Ae. sollicitans is capable of functioning as an epidemic vector in the coastal areas of New Jersey where human cases of EEE have been most common.

Abstract: Venezuelan encephalitis (VE) virus has intermittently produced epidemics and equine epizootics on the dry Pacific coastal plain of Peru since at least the 1930's. However, evidence that the virus exists in the Amazon region of Peru to the east of the Andes mountains was not obtained until antibodies were found in human sera collected in 1965, and 10 strains of the virus were isolated in a forest near the city of Iquitos, Peru during February and March 1971. Eight strains came from mosquitoes and two from dead sentinel hamsters. Three hamsters exposed in forests near Iquitos developed VE virus antibodies suggesting that hamster-benign strains also exist there. Antibody tests of equine sera revealed no evidence that VE virus was actively cycling during the late 1950's or 1960's in southern coastal Peru, where equine epizootics had occurred in the 1930's and 1940's. In northern coastal Peru bordering Ecuador, antibodies were present in equine sera, presumably residual from the 1969 outbreak caused by subtype I virus, since neutralizing antibody titers were higher to subtype I virus than to subtypes III or IV. No VE virus was detected in this northern region during the dry season of 1970 by use of sentinel hamsters. The possibility is considered that VE epidemics and equine epizootics on the Pacific coast of Peru are caused by movements of virus in infected vertebrates traversing Andean passes or in infected vertebrates or mosquitoes carried in airplanes from the Amazon region.

Abstract: Three horses (Equus caballus) with a history of performing cognitive tasks including discrimination learning, categorization, and concept use were tested to evaluate their long-term memory (LTM) in three experiments. In addition, use of LCD multi-displays for stimulus presentation was incorporated into cognition testing protocol for the first time with horses. Experiment 1 tested LTM for discrimination learning that originally occurred 6 years earlier. Five sets of stimuli were used and the two horses tested showed no decrement in performance on four of the sets; however, both horses did score below chance on one set. Experiment 2 examined long-term categorization recall 10 years after horses had demonstrated the ability to make stimulus selections based on shared characteristics within a given category. The horse tested for LTM after the decade-long interval immediately and consistently applied the previously learned categorization rule to not only familiar but also novel sets of stimuli. Experiment 3 tested another horse for LTM for a relative size concept. This horse had originally demonstrated concept rule use in order to select stimuli based on their relative size to one another. More than 7 years later and without further training, this horse reliably applied the previously established size concept to both familiar and novel sets of stimuli. These findings are the first reports of long-term categorical and conceptual memory in horses and are consistent with observations of domestic and wild horses, which indicate that behavioral and ecological events may be remembered for long periods of time. These studies also demonstrate the adaptive nature of horses with regard to their ability to generalize over several different testing conditions.

Abstract: This presentation will include commentary on work presented at this meeting as representative of the rapidly growing body of equine behavior science evidence relevant to human-horse interaction and the welfare of domestic, feral, and wild horses.
A substantial literature has accumulated detailing the behavior patterns of wild and feral equid populations, and to some extent the behavior of horses in various domestic environments. Professor Klingel“s and Professor Houpt”s work, begun nearly 40 years ago, continues to inspire colleagues around the world to qualitatively and quantitatively describe behavior of equids in a variety of environments. Several examples of the importance of this type of work to human-horse interaction and horse welfare are evident in throughout the meeting. It forms the basis for assessing the disturbance of behavior in wildlife management projects such as fertility manipulations (Hopkins; Ransom & Cade) or species reintroduction (Kaczensky et al). Study of the apparent variability in observations among the populations will lead to a better understanding of environmental and other factors, which will have fruitful application to welfare of horses both in domestic and natural environments. Unfortunately, this work always brings to mind what I perceive as a nagging threat to horse welfare and quality of human-horse interaction is misinformation concerning natural horse behavior. Natural horse behavior seems to be of great general interest, but unfortunately inaccuracies and misinterpretations are pervasive in popular “horse culture” and continue to be a conspicuous influence on management and training of domestic horses. Unfortunately, this misinformation often makes its way and influences equine education, both lay and equine science/veterinary education. Comparative observational study of behavior of horses in all settings by trained behaviorists, along with research designed to address purported implications for management of domestic horses, along with initiatives to transfer knowledge to educators at all levels should be encouraged.

Included in this meeting is considerable work addressing questions of domestic management practices such as forced weaning, transportation, stabling, and arbitrary grouping and regrouping of horses. This adds to a growing body of applied physiology and behavior research that has established trained behaviorists as a critical resource on teams making decisions on humane management.
Also well represented in work presented at this meeting is the exploration of cognition, perception, and temperament in horses. It is personally pleasing to see examples of direct investigation of the ability of the horse to respond to subtle human posture and gesture, which for many of us has represented just annoying possible confounders of earlier cognition studies. Behaviorists trained in perception and learning will no doubt contribute enormously to this exciting area of investigation.

Abstract: This study investigates the ability of horses to recall a feeding event in a two-point choice apparatus. Twelve horses were individually tested whereby they were maintained immobile in a test arena and visually and aurally experienced the delivery of food into one of two feed goals. The horses were then released to make their choice in two experimental contexts: immediate release after experiencing the delivery of food, and release 10 s after food delivery. Each horse performed 40 immediate-release (IR) trials, followed by forty 10-s release trials over a 3-day period. In addition, the same horses were tested 3 months later in the spring with the same number and sequence of trials. Results were analysed by log-linear analysis of frequencies. Results showed that while horses were able to achieve the correct feed goal choice in the immediate-release trials, they were unsuccessful with the 10-s release trials. This suggests that there are limitations in recall abilities in horses, in that they may not possess a prospective type of memory. There are welfare and training implications in these findings concerning the effects of overestimating the mental abilities of horses during training and the effects of delays in reinforcements.