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Klingel H,. (1987). Unpaarhufer, Pferde. in Grzimek B (ed): Grzimeks Enzyklopädie Säugetiere, 4, 548–592, Kindler.
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Mcinnis Ml, V. M. (1987). Dietary relationships among feral horses, cattle, and pronhorn in southeastern Oregon. J Range Mgmt, 40, 60–66.
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Olivier W,. (1987). Is it possible to bring back the quagga? Roan News, 4, 1–2.
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Penzhorn Bl,. (1987). Descriptions of incisors of known – age Cape Mountain Zebras from the Mountain Zebra National park. Onderstepoort J vet Res, 54, 135–141.
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Penzhorn Bl, G. R. (1987). Incisor wear in free – ranging Cape mountain zebras. S Afr J Wildl Res, 17, 99–102.
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Penzhorn Bl, L. P. (1987). Comparisons of reproductive parameters of two Cape mountain zebra populations. J Reprod Fert Suppl, 35, 661–663.
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Schilder Mbh, B. P. (1987). Ethological investigations on a herd of Plains Zebra in a safari park: Time – budgets, reproduction and food competition. App Anim Behav Sci, 18, 45–56.
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SUMMERS PM et al,. (1987). Sucessful transfer of the embryos of Przewalski's horses and Grant's zebra to domestic mares. J Reprod Fert, 80, 13–20.
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Lane, J. G., & Mair, T. S. (1987). Observations on headshaking in the horse. Equine Vet J, 19(4), 331–336.
Abstract: The clinical records of 100 cases of headshaking in horses were reviewed. Possible causes of the abnormal behaviour were identified in 11 animals; these included ear mite infestation, otitis interna, cranial nerve dysfunction, cervical injury, ocular disease, guttural pouch mycosis, dental periapical osteitis and suspected vasomotor rhinitis. However, in only two of these could it be shown that correction of the abnormality led to elimination of the headshaking. The additional clinical signs exhibited by the other idiopathic cases of headshaking included evidence of nasal irritation, sneezing and snorting, nasal discharge, coughing and excessive lacrimation. Many of these horses also showed a marked seasonal pattern with respect to the onset of the disease and the recurrence of signs in subsequent years. The clinical presentation of idiopathic headshakers and the seasonal incidence of the signs closely resemble allergic rhinitis in man.
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Sherwin, C. M., & Johnson, K. G. (1987). The influence of social factors on the use of shade by sheep. Appl. Anim. Behav. Sci., 18(2), 143–155.
Abstract: Individual differences in shading behaviour within a flock of sheep could be due to differences in thermoregulatory capabilities or to the influence of social factors. The possible influence of social factors on shade-use is examined in this paper. Two measures of dominance were made on 39 Merino wethers. These were based on the hierarchy determined by butting during feeding and on priority of access to limited feed. Leadership was also assessed while driving the sheep to a woolshed and as the sheep entered weighing scales. These behavioural traits were compared with leadership to shade and shade-use observed on 9 days during summer in a small pastureless enclosure containing natural shade. Maximum ambient temperature on these 9 days varied between 29.0 and 39.5[degree sign]C. All behavioural traits examined were significantly repeatable. The two dominance ranks were negatively correlated (P<0.05). The butting hierarchy was correlated with shading behaviour; those sheep that butted the larger proportion of the flock were seen to shade for longer periods of time (P=0.05). This relationship became more significant as environmental temperature increased. Significant (P<0.05) differences in the amount of time each sheep spent shading were evident throughout the flock, but in particular seven individuals shaded much less than others. Shade-use increased in hot weather and was slightly more strongly correlated with radiation load than with air temperature. The non-shading leadership ranks were related neither to each other nor to the leadership to shade. However, the sheep that moved to shade first remained there longest (P<0.05). Reduced motivation to feed did not appear to explain early movement to shade. Few overtly aggressive or other interactions between animals were seen to be associated with movements to or within shade. Nonetheless, the results indicate that social forces do exert some influence on shade-use.
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