Evaluation of Usefulness of Equine Appeasing Pheromone
in Gentling of Foals and Yearlings

Equine Appeasement Pheromone (EAP) is a product available in Europe for use in calming horses (Pherosynthese, Le Rieu Neuf, Saint Saturnin d’Apt, France). The product is a synthetic pheromone based on a natural pheromone secreted from specialized glands associated with the mammary glands.  The pheromone is believed to be conserved across all mammals, including humans. The same pheromone, known as Porcine Appeasing Pheromone, used in pigs at weaning and group mixing has been reported to decrease certain types of injuries and increase average daily weight gain (Pageat and Tessier, 1998a, and 1998b).  Reports of studies in horses undertaken by the developing company, Pherosynthese Research Center, indicate that EAP resulted in decreased heart rate during and decreased time to approach a ‘fear eliciting test’ (Patrick Pageat, personal communication, 2000).  Our behavioral observations of horses would indicate during moments of apparent stress or fear, foals and yearlings do indeed exhibit an udder-nuzzling behavior that appears to have a calming effect on the foal.

The process of initial handling (gentling) and training of young horses can be a source of stress.  For the welfare of both the animal and the handler as well as for efficiency of the process, it is likely useful to minimize fear and stress during initial handling and training of horses.  The purpose of this project was to evaluate the potential effectiveness of EAP in the gentling of previously un-handled foals and yearlings.  Two related hypotheses are that EAP will reduce fear and thereby facilitate human animal interaction and increase efficiency of the process of gentling foals and yearlings.  The general design included between-group comparison of EAP and vehicle treated controls on the effort and time to achieve a battery of specific handling goals during a standard series of gentling sessions.

Ten foals and 7 yearlings belonging to a semi-feral pony herd at the New Bolton Center of the University of Pennsylvania School of Veterinary Medicine were assigned as age-matched pairs to either EAP or control treatment.  EAP treatment consisted of exposure to 1ml of EAP liquid on a cotton glove worn by the individual during the gentling procedures.  Control treatment consisted of similar exposure to sterile water (CONTROL).  The gentling procedure consisted of a series of handling sessions to achieve compliance with the 19 specific handling and restraint goals listed in Table 1.  The compliance goals were selected as those specifically needed for routine and research interaction with these animals, and were similar to compliance goals generally required for on-farm handling and care of horses and ponies.  Work proceeded generally in the order listed, with modifications as needed for individual subjects. Each session consisted of positive reinforcement-based systematic desensitization to the various forms of contact and restraint. The target duration of each session was 15 to 30 minutes depending upon progress during the session, trying to end each session during positive interaction. Almost all work was done in an 8 ft. X 8 ft. semi-padded catch pen with the dam and remaining harem members in adjacent enclosures within the semi-feral pasture.  For leading, some subjects were moved into a 16 ft X 16 ft enclosure.  Three subjects that had appeared somewhat anxious when in the enclosed work area each also received one session in an open field situation.

The handling procedures were done between June 26 and July 25, 2002.  Progression through the 19 specific compliance tasks was fairly standard in the order listed in Table 1, but modified as judged useful by the handler to meet individual animal temperament and sensitivities to specific handling. The sessions of the 17 subjects were done in the order that opportunities arose for convenient and safe access to the particular subject.   The gentling procedures were done by one person who was familiar with the principals of behavior modification with other species but who had no previous experience or knowledge of horse handling.  Training specifically for this task included 2 hours of introduction to the general principals of horse handling and specific gentling techniques for foals and yearlings, as well as approximately 4 hours of consultation or direct assistance by an experienced horse handler with challenging situations arose with particular subjects.

Table 1
19 Specific Compliance Tasks
Approach Handler
Tolerate Manipulation of Muzzle and Nostrils
Face
Ears
Eyes
Neck and Shoulder
Body (Back and Barrel and Belly)
Rump
Weight Tape Around Girth
Auscultation
Simulated Jugular Stick
Halter
Tail, Anus and Perineum
Udder/Male Genitals
Oral Exam
Front Legs and Feet
Hind Legs and Feet
Tie
Lead

Sessions were video recorded for subsequent measure of duration of contact to achieve each compliance goals the total duration of contact to reach full compliance with the set of 19 specific goals, and the frequency and duration of behavior indicating fear and stress, as well as heart and respiratory rates were recorded during a final session following achievement of full compliance, during which the subject was exposed to a handling challenge incorporating all 19 compliance goals under open pasture conditions.

All personnel remained blind to treatment assignment of subjects until procedures and data analyses were complete.

Interim Results

            To date, all 17 subjects have successfully reached full compliance, and are now ready for the open-field challenge handling and examination sessions.  Among subjects, full compliance was reached within 3 to 5 handling sessions (mean 4.18 + 0.17) each with a duration of 10 to 52 minutes, for a total contact time of 74 to 160 minutes (96.7 + 5.8) contact time per subject.

        Subjects exposed to EAP  required 3 to 5 (mean 4.2 + 0.7) sessions for a total of 76 to 160 (mean, 101.6 + 10.1) minutes compared to CONTROL with a range of 74 to 114 (mean, 91.2 + 4.9 minute).  These differences are not significant.

            Subjects were also ranked (1 to 17) based primarily on measures of total time and number of sessions to achieve full compliance, and secondarily on the technician’s subjective rating of overall ease of gentling.  Ranks were similar for EAP and CONTROL group (Wilcoxin Rank Sum, p > 0.10).

            Duration of contact to reach compliance for each specific task, as well as frequency and duration of behaviors indicating fear and stress are yet to be analyzed. Heart and respiratory rates and total time to complete a routine examination during an open-field challenge have also not yet been analyzed.  

Foals required a mean of 102.6 + 8.7 and yearlings a mean of 93 + 7.2 minutes of total contact time to reach compliance.  Males required 103.4 +8.4 and females 92.1 + 7.8 minutes of total contact time to reach full compliance.  These differences are not significant (p >0.10, independent t-test).

Discussion

Results so far with these 17 previously unhandled foals and yearlings living under semi-feral conditions indicate no effect of EAP on efficiency of gentling. 

The total contact time to reach full compliance with 19 specific handling and restraint goals for these 17 previously unhandled foals and yearlings was just under 28 hours.  This represents extraordinary efficiency and success.  These results are similar to results of gentling procedures done within this herd in 2000 (Alarcon and McDonnell, unpublished).  In that work, 37 previously unhandled ponies, ages 1 week to 3 years, in a series of one to several 10- to 20-minute sessions, required an average of 89.7 + 4.7 minutes to reach compliance on a similar set of handling goals.  That work was done under mostly open field, as opposed to primarily small catch pen conditions as was done in the present study.  As in this present study, the technician was mostly inexperienced with horse handling.  For both studies, the technicians, though completely naïve or fairly novice at handling horses, were judged by experienced collaborators to carefully follow good behavior modification technique, using a gentle persistent approach with only positive reinforcement, and no punishment.  Both took care to avoid inadvertent strongly negative consequences of escape or avoidance behaviors.  For each technician, timing of positive reinforcement and careful pairing of the primary and secondary reinforcement, as well as consistency of verbal secondary reinforcement, improved from awkward initially to satisfactory as the work progressed.  Together these studies suggest that good results and extraordinary efficiency can be achieved by technicians with little or no previous  horse handling experience.

References

Pageat P and Tessier Y (1998a) Can a pig pheromone analogue improve daily weight gain and food conversion efficiency in post-weanlings?  Congr. Internat. Pig Vet. Soc., Birmingham, UK, p.401.

Pageat P and Tessier Y (1998b) Usefulness of a porcine pheromone analogue in the reduction of aggressions between weanlings on penning; behavior study. Congr. Internat. Pig Vet. Soc., Birmingham, UK, p.413.