Abstract: OBJECTIVE: To determine signalment, history, clinical signs, duration, seasonality, and response to various treatments reported by owners for headshaking in horses. DESIGN: Owner survey. ANIMALS: 109 horses with headshaking. PROCEDURE: Owners of affected horses completed a survey questionnaire. RESULTS: 78 affected horses were geldings, 29 were mares, and 2 were stallions. Mean age of onset was 9 years. Headshaking in 64 horses had a seasonal component, and for most horses, headshaking began in spring and ceased in late summer or fall. The most common clinical signs were shaking the head in a vertical plane, acting like an insect was flying up the nostril, snorting excessively, rubbing the muzzle on objects, having an anxious expression while headshaking, worsening of clinical signs with exposure to sunlight, and improvement of clinical signs at night. Treatment with antihistamines, nonsteroidal anti-inflammatory drugs, corticosteroids, antimicrobials, fly control, chiropractic, and acupuncture had limited success. Sixty-one horses had been treated with cyproheptadine; 43 had moderate to substantial improvement. CONCLUSIONS AND CLINICAL RELEVANCE: Headshaking may have many causes. A large subset of horses have similar clinical signs including shaking the head in a vertical plane, acting as if an insect were flying up the nostrils, and rubbing the muzzle on objects. Seasonality and worsening of clinical signs with exposure to light are also common features of this syndrome. Geldings and Thoroughbreds appear to be overrepresented. Cyproheptadine treatment was beneficial in more than two thirds of treated horses.

Abstract: Nine yearling horses, stabled in individual stalls, were used in a trial to determine the diurnal pattern of wood chewing and the effects of exercise on this behavior. The trial was a Latin square design conducted over three 2-wk periods during which each horse was exposed to each of the three following treatments: 1) no exercise (NE), 2) exercise after the morning feeding (AM), and 3) exercise in the afternoon (PM). Horses were fed a complete pelleted feed in the morning and both pelleted feed and long-stemmed hay in the afternoon. Exercise consisted of 45 min on a mechanical walker followed by 45 min in a paddock with bare soil. Each stall was equipped with two untreated spruce boards during each period for wood chewing. Wood chewing was evaluated by videotaping each horse for 22 h during each period, determining the weight and volume of the boards before and after each period, and by visual appraisal of the boards. Intake of trace mineralized salt was also measured. Wood chewing occurred primarily between 2200 and 1200. All measures of wood chewing were correlated when totals for the entire 6 wk were analyzed. When analysis was performed on 2-wk values, videotape results were not correlated with volume or weight loss of boards. Horses chewed more when on the NE treatment (511 s/d) than when on AM or PM (57 and 136 s/d, respectively; P less than .05). Salt intake tended to be greater for NE than for the other treatments (P less than .10).(ABSTRACT TRUNCATED AT 250 WORDS)

Abstract: Past studies of galliform anti-predator behavior show that they discriminate between aerial and ground predators, producing distinctive, functionally referential vocalizations to each class. Within the category of aerial predators, however, studies using overhead models, video images and observations of natural encounters with birds of prey report little evidence that galliforms discriminate between different raptor species. This pattern suggests that the aerial alarm response may be triggered by general features of objects moving in the air. To test whether these birds are also sensitive to more detailed differences between raptor species, adult chickens with young were presented with variously sized trained raptors (small, intermediate, large) under controlled conditions. In response to the small hawk, there was a decline in anti-predator aggression and in aerial alarm calling as the young grew older and less vulnerable to attack by a hawk of this size. During the same developmental period, responses to the largest hawk, which posed the smallest threat to the young at all stages, did not change; there were intermediate changes at this time in response to the middle-sized hawk. Thus the anti-predator behavior of the adult birds varied in an adaptive fashion, changing as a function of both chick age and risk. We discuss these results in light of current issues concerning the cognitive mechanisms underlying alarm calling behavior in animals.

Abstract: Although the Piagetian framework has been used by numerous researchers to compare cognitive abilities of diverse species, the system is often criticized as implemented. I examine the various criticisms, suggest ways in which the system can be improved, and argue for the need for descriptive systems such as the Piagetian framework to complement programs that look for cellular and molecular bases or mathematical models to explain behavior.