Abstract: A group of six chimpanzees was placed in a social learning situation, without training. The learning task was an operant conditioning situation; that is, a subject had to pull two handles simultaneously to cause a piece of fruit to fall into the cage. Only three individuals acquired the operant behaviour. For the operant individuals, social influences on the expression of the learning task were then examined; the dominant chimpanzee during feeding had an inhibiting effect when close to the operant subjects. Depending on the subject, social factors may influence not only the specific expression of what is learnt, but also the nature of what is learnt. Chimpanzees appear to experience situations differently: they develop an individual problem-solving strategy according to their social relationships even if the experimental procedure is the same for all.

Abstract: This study reports on leadership behavior in a domestic goat group (370 animals) moving from night-time areas to grazing areas. Of the adult females which occupied leadership positons, all of them were born in the study area. Also, they were individuals with more relatives alive in the group (according to matrilineal kinship) than the rest, but they did not show special physical characteristics.

Abstract: Sixteen horses were used to determine if number of trials given per training session (5, 10, 15 or 20) affected learning performance in an avoidance conditioning task. The horse had to move from one side of a test pen to the other during an auditory cue presentation to avoid aversive stimulation. A pen 8 mx3.6 m, divided into two equal sections by a 13-cm diameter plastic pipe lying on the ground, was used as the test pen. Painted plywood panels were fastened to the fence in half the pen to help horses distinguish visually between the two parts. A 10-s auditory cue was used as a signal for horses to move from one side of the test pen to the other. A 20-s intertrial interval was used. Training sessions were conducted every third day. Each trial was recorded as an avoidance (the horse completed the task during auditory cue presentation and avoided aversive stimulus) or an error (the horse received aversive stimulus). After completing ten consecutive avoidances (criterion), the horse was removed from the study. Numbers of training sessions, trials, avoidances and errors until reaching criterion were recorded for each horse. Horses varied greatly within these variables with ranges of 3-18 sessions, 37-121 trials, 20-68 avoidances and 17-53 errors to criterion. No differences were detected (P>0.05) in the number of conditioning trials per training session (treatment) for the mean number of trials, avoidances or errors to criterion. Number of training sessions to criterion differed (P<0.01) among treatments, indicating that an optimum number of learning trials per training session might exist. Mean sessions to criterion for horses receiving 5, 10, 15 and 20 trials per session were 15.1+/-1.3, 5.8+/-1.1, 5.3+/-1.1 and 4.6+/-1.1, respectively. Regression analysis indicated that 16.2 trials per training session would minimize number of sessions to criterion. Although it is widely assumed that learning efficiency in horses is decreased when intense activity is concentrated into a small number of sessions, these results indicate that moderate repetition of training activities is needed for efficient learning.

Abstract: The time-motion characteristics of Canadian basic- and medium-level dressage competitions are described, and the results are applied in formulating sport-specific conditioning programs. One competition was analyzed at the six levels from basic 1 to medium 3. Each test was divided into a series of sequences based on the type and speed of activity. The durations of the sequences were measured from videotapes. The basic-level tests had fewer sequences, and they were shorter in distance and duration than the medium tests (P < 0.10), but the average speed did not differ between the two levels. It is recommended that horses competing at the basic levels be conditioned using 5-min exercise periods, with short (10-s) bursts of lengthened trot and canter included at basic 2 and above. In preparation for medium-level competitions, the duration of the work periods increases to 7 min, 10- to 12-s bursts of medium or extended trot and canter are included, and transitions are performed frequently to simulate the energy expenditure in overcoming inertia.

Abstract: The pressure exerted on a flat level surface by recently trimmed, unshod hoofs of the front limbs of 23 sound, adult horses was measured using pressure-sensitive film and a specially built cassette. The horses were tranquilized and stood with one foot on the 2.9-cm-thick cassette and the other on a block of equal height. The hoofs were observed for motion during the measurement, and the developed film was examined for improper alignment of the film or slipping of the hoof. The center of pressure was located using the method of weighted proportions of Barrey. This static measurement system with a long measurement time and the number of measurements reduced the influence of variables inherent in the horses' behavior and the measuring system. The calculated point was recorded as falling medial to, lateral to or on a line bisecting the central sulcus of the frog. In the dorsal to palmar orientation the point was classified with reference to a line drawn halfway between the most dorsal and the most palmar mark on the film. Forty-six percent of the calculated centers of pressure were located in the medial heel area. Binomial analysis for large samples indicates that this was a significant variation from a random distribution. Seventy-six percent of the centers were located in or on the borders of the medial heel.