BEHAVIORAL AND PHYSIOLOGICAL RESPONSES OF HORSES TO INITIAL TRAINING: THE
COMPARISON BETWEEN PASTRUE VERSUS STALLED HORSES
E. Rivera; S. Benjamin; A. Morrison; L. Callender; B. D. Nielsen and A.
J. Zanella. Michigan State University, East Lansing, MI.
Pasture kept horses have the ability to interact socially and are exposed
to a richer environment but have less contact with humans. Horses kept
in stalls have greater exposure to human contact however they lack social
interaction. There are evidences, for several species, that learning ability
may be impaired in animals housed in social isolation or barren environment.
In the present work the behavior and physiological responses to initial
training was monitored in stall (S) and pasture (P) kept horses. Sixteen,
2 year old Arabian horses were involved in the present study. Twelve horses
were subjected to a standardized "training procedure" (6P & 6S) and
4 (2P & 2S) animals were selected as control (C). Training was carried
out by two trainers who handled both pasture and stall kept horses. The
horses, which were never ridden before, were kept in pasture or in individual
stalls for three months prior to this experiment. Behavioral observation
assessing the interactions between the trainer and the horse in training
were collected using video recorder and data was analyzed using a behavior
observation software. Measures of plasma cortisol were monitored by radioimmunoassay
in blood samples collected by jugular puncture in training days 1, 7, 21
and 28. Samples were collected prior to training (basal), immediately post-training
(pt), 15 minutes post training (pt15) and 60 minutes post-training (pt60).
During the first training day, horses were haltered and lead to the round
training pen where they were released. The horse was caught and gradually
the trainer began to get the horse accustomed to handling, being saddled,
mounted and ridden within an average of 30 minutes. The horses were encouraged
to walk, trot and canter in each direction. Control horses were released
into the round pen and left to explore the environment for 30 minutes.
Additional tasks were incorporated during days 7, 21 and 28 of training
protocol. Horses kept in stalls showed significantly higher frequency of
behavioral patterns associated with resistance to training than pasture
kept horses. Bucking and jumping (S=3.83 q 10.81SEM and P=1.09 q 10.30SEM,
p<0.05) head tossing (S=5.17 q 11.29SEM and P=2.04 q 1.74SEM ) tucking
of tail (S=6.08 q 11.35SEM and P=2.09 q 1.526SEM ) were performed more
by stall housed horses. Stall housed horses ran for longer periods in the
training pen than pasture kept horses (S=7.10 q 11.04SEM and P=2.21 q 1.753SEM
). Increase in salivary cortisol in response to training, tended to be
higher in stall housed horses for all the samples taken in the four experimental
days, but the difference only approached significance (p=0.08, df, F-2.62)
in samples collected immediately post-training (pt). The highest increase
in plasma cortisol levels was observed in the first training day and the
lowest was observed at the day 28. The difference among training days was
significant (df 3; f=7.16; p=0.0004). Differences between basal cortisol
levels and post-training levels were not evident for control horses in
days 7, 21 and 28 post-training. Effective training may be accomplished
in rather short time using humane techniques. Housing conditions seems
to have a significant effect on the behavioral responses of horses to training
but no effect on plasma cortisol levels. These results may generate recommendations
that could be given to horse owners on which training technique and housing
conditions that would maximize the success of training procedures.