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Houpt, K. A., & Feldman, J. (1993). Animal behavior case of the month. Aggression toward a neonatal foal by its dam. J Am Vet Med Assoc, 203(9), 1279–1280.
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Kirkpatrick, J. F., & Turner, A. (2003). Absence of effects from immunocontraception on seasonal birth patterns and foal survival among barrier island wild horses. J Appl Anim Welf Sci, 6(4), 301–308.
Abstract: Despite a large body of safety data, concern exists that porcine zonae pellucidae (PZP) immunocontraception--used to manage wild horse populations--may cause out-of-season births with resulting foal mortality. Our study at Assateague, Maryland indicated the effects of immunocontraception on season of birth and foal survival between 1990 and 2002 on wild horses from Assateague Island. Among 91 mares never treated, 69 (75.8%) of foals were born in April, May, and June (in season). Among 77 treated mares, 50 (64.9%) were born in season. Of 29 mares foaling within 1 year after treatment (contraceptive failures), 20 (68.9%) were born in season. Of 48 mares treated for greater than 2 years then withdrawn from treatment, 30 (62.5%) of 48 foals were born in season. There were no significant differences (p <.05) between either treatment group or untreated mares. Survival did not differ significantly among foals born in or out of season or among foals born to treated or untreated mares. Data indicate a lack of effect of PZP contraception on season of birth or foal survival on barrier island habitats.
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Mrosovsky, N., & Shettleworth, S. J. (1974). Further studies of the sea-finding mechanism in green turtle hatchlings. Behaviour, 51(3-4), 195–208.
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Collery, L. (1974). Observations of equine animals under farm and feral conditions. Equine Vet J, 6(4), 170–173.
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Owren, M. J., Dieter, J. A., Seyfarth, R. M., & Cheney, D. L. (1993). Vocalizations of rhesus (Macaca mulatta) and Japanese (M. fuscata) macaques cross-fostered between species show evidence of only limited modification. Dev Psychobiol, 26(7), 389–406.
Abstract: Two rhesus and two Japanese macaque infants were cross-fostered between species in order to study the effects of auditory experience on vocal development. Both the cross-fostered and normally raised control subjects were observed over the first 2 years of life and their vocalizations were tape-recorded. We classified 8053 calls by ear, placed each call in one of six acoustic categories, and calculated the rates at which different call-types were used in different social contexts. Species differences were found in the use of “coo” and “gruff” vocalizations among control subjects. Japanese macaques invariably produced coos almost exclusively. In contrast, rhesus macaques produced a mixture of coos and gruffs and showed considerable interindividual variation in the relative use of one call type or the other. Cross-fostered Japanese macaques adhered to their species-typical behavior, rarely using gruffs. Cross-fostered rhesus subjects also exhibited species-typical behavior in many contexts, but in some situations produced coos and gruffs at rates that were intermediate between those shown by normally raised animals of the two species. This outcome suggests that environmentally mediated modification of vocal behavior may have occurred, but that the resulting changes were quite limited.
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Henry, S., Richard-Yris, M. - A., & Hausberger, M. (2006). Influence of various early human-foal interferences on subsequent human-foal relationship. Dev Psychobiol, 48(8), 712–718.
Abstract: Whereas the way animals perceive human contact has been particularly examined in pet animals, a small amount of investigations has been done in domestic ungulates. It was nevertheless assumed that, as pet animals, non-aggressive forms of tactile contact were as well rewarding or positive for these species, even though the features of intraspecific relationships in pet animals and domestic ungulates may be to some extent different.We test here the hypothesis that horses may not consider physical handling by humans as a positive event. When comparing different early human-foal interactions, we found that early exposure to a motionless human enhanced slightly foals reactions to humans whereas forced stroking or handling in early life did not improve later human-foal relation. Foals that were assisted during their first suckling (e.g., brought to the dam's teat) even tended to avoid human approach at 2 weeks, and physical contact at 1 month of age.We argue that interspecies differences may exist in how tactile stimulation is perceived. It may be important for the establishment of a bond that a young animal is active in the process and able, through its behavioral responses, to help define what is positive for it. This way of investigation may have important general implications in how we consider the development of social relations, both within and between species.
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Williams, J. L., Friend, T. H., Collins, M. N., Toscano, M. J., Sisto-Burt, A., & Nevill, C. H. (2003). Effects of imprint training procedure at birth on the reactions of foals at age six months. Equine Vet J, 35(2), 127–132.
Abstract: REASONS FOR PERFORMING STUDY: While imprint training procedures have been promoted in popular magazines, they have received limited scientific investigation. OBJECTIVES: To determine the effects of a neonatal imprint training procedure on 6-month-old foals and to determine if any one session had a greater effect than others. METHODS: Foals (n = 131) were divided into the following treatments: no imprint training, imprint training at birth, 12, 24 and 48 h after birth or imprint training only at birth, 12, 24, 48, or 72 h after birth. Foals then received minimal human handling until they were tested at 6 months. RESULTS: During training, time to complete exposure to the stimulus was significant for only 2 of 6 stimuli. Percentage change in baseline heart rate was significant for only 2 of 10 stimuli. These 4 effects were randomly spread across treatments. CONCLUSIONS: Neither the number of imprint training sessions (0, 1, or 4) nor the timing of imprint training sessions (none, birth, 12, 24, 48, or 72 h after birth) influenced the foal's behaviour at 6 months of age. POTENTIAL CLINICAL RELEVANCE: In this study, imprint training did not result in better behaved, less reactive foals.
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Bard, K. A. (2007). Neonatal imitation in chimpanzees (Pan troglodytes) tested with two paradigms. Anim. Cogn., 10(2), 233–242.
Abstract: Primate species differ in their imitative performance, perhaps reflecting differences in imitative capacity. The developmentally earliest form of imitation in humans, neonatal imitation, occurs in early interactions with social partners, and may be a more accurate index of innate capacity than imitation of actions on objects, which requires more cognitive ability. This study assessed imitative capacity in five neonatal chimpanzees, within a narrow age range (7-15 days of age), by testing responses to facial and vocal actions with two different test paradigms (structured and communicative). Imitation of mouth opening was found in both paradigms. In the communicative paradigm, significant agreement was found between infant actions and demonstrations. Additionally, chimpanzees matched the sequence of three actions of the TC model, but only on the second demonstration. Newborn chimpanzees matched more modeled actions in the communicative test than in the structured paradigm. These performances of chimpanzees, at birth, are in agreement with the literature, supporting a conclusion that imitative capacity is not unique to the human species. Developmental histories must be more fully considered in the cross-species study of imitation, as there is a greater degree of innate imitative capacity than previously known. Socialization practices interact with innate and developing competencies to determine the outcome of imitation tests later in life.
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Muscatello, G., Anderson, G. A., Gilkerson, J. R., & Browning, G. F. (2006). Associations between the ecology of virulent Rhodococcus equi and the epidemiology of R. equi pneumonia on Australian thoroughbred farms. Appl Environ Microbiol, 72(9), 6152–6160.
Abstract: The ecology of virulent strains of Rhodococcus equi on horse farms is likely to influence the prevalence and severity of R. equi pneumonia in foals. This study examined the association between the ecology of virulent R. equi and the epidemiology of R. equi pneumonia by collecting air and soil samples over two breeding seasons (28 farm-year combinations) on Thoroughbred breeding farms with different reported prevalences of R. equi pneumonia. Colony blotting and DNA hybridization were used to detect and measure concentrations of virulent R. equi. The prevalence of R. equi pneumonia was associated with the airborne burden of virulent R. equi (both the concentration and the proportion of R. equi bacteria that were virulent) but was not associated with the burden of virulent R. equi in the soil. Univariable screening and multivariable model building were used to evaluate the effect of environmental and management factors on virulent R. equi burdens. Lower soil moisture concentrations and lower pasture heights were significantly associated with elevated airborne concentrations of virulent R. equi, as were the holding pens and lanes, which typically were sandy, dry, and devoid of pasture cover. Few variables appeared to influence concentrations of virulent R. equi in soil. Acidic soil conditions may have contributed to an elevated proportion of virulent strains within the R. equi population. Environmental management strategies that aim to reduce the level of exposure of susceptible foals to airborne virulent R. equi are most likely to reduce the impact of R. equi pneumonia on endemically affected farms.
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Takai, S., Fujimori, T., Katsuzaki, K., & Tsubaki, S. (1987). Ecology of Rhodococcus equi in horses and their environment on horse-breeding farms. Vet Microbiol, 14(3), 233–239.
Abstract: Quantitative culture of R. equi in the feces of dams and foals, in the air of the stalls and in the soil of the paddocks was carried out on three horse-breeding farms during the foaling season. The isolation rates of R. equi from the feces of dams from the 3 farms suddenly increased to approximately 80% at the end of March, when the snow in the paddocks finished melting, and remained at that level during April and May. The mean number of R. equi and the isolation rate of R. equi from the feces of dams on the farms were investigated for 5 weeks before and 5 weeks after delivery. During the 10 weeks, there were no differences in the isolation rate or in the mean number of R. equi from the feces of dams. R. equi was first isolated from the feces of the foals born in February and the middle of March at 3-4 weeks of age, on the other hand, it was first isolated from the feces of foals born in the end of March and April at 1-2 weeks of age. The number of R. equi in the soil collected from the paddocks used by dams during the winter was approximately 10(2)-10(4) g-1 of soil during the experiment. R. equi was isolated from the air in the stalls at the end of March and the number of R. equi in the air increased particularly on dry and windy days.(ABSTRACT TRUNCATED AT 250 WORDS)
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