Pickerel, T. M., Crowell-Davis, S. L., Caudle, A. B., & Estep, D. Q. (1993). Sexual preference of mares (Equus caballus) for individual stallions. Appl. Anim. Behav. Sci., 38(1), 1–13.
Abstract: Eight mares were tested to determine if they remained near one of two stallions longer than would be expected if association was random. Six stallions were paired in 30 combinations and each mare was tested 30 times. The mares (Equus caballus) demonstrated a definite preference for individual stallions throughout the breeding season. This preference was influenced by the estrous state of the mare. During estrus, mares' preferences for stallions were positively correlated with the rate at which a given stallion vocalized. During diestrus, mares spent significantly less time in the proximity of stallions and did not exhibit any preference for individual stallions.
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Hall, C., Crowell-Davis, S. L., & Warren, R. J. (1993). Maternal and developmental behavior of the feral horses of Cumberland Island, Georgia. Appl. Anim. Behav. Sci., 37(1), 85.
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Mellor, P. S. (1993). African horse sickness: transmission and epidemiology. Vet Res, 24(2), 199–212.
Abstract: African horse sickness (AHS) virus causes a non-contagious, infectious, arthropod-borne disease of equines and occasionally of dogs. The virus is widely distributed across sub-Saharan African where it is transmitted between susceptible vertebrate hosts by the vectors. These are usually considered to be species of Culicoides biting midges but mosquitoes and/or ticks may also be involved to a greater or lesser extent. Periodically the virus makes excursions beyond its sub-Saharan enzootic zones but until recently does not appear to have been able to maintain itself outside these areas for more than 2-3 consecutive years at most. This is probably due to a number of factors including the apparent absence of a long term vertebrate reservoir, the prevalence and seasonal incidence of the vectors and the efficiency of control measures (vaccination and vector abatement). The recent AHS epizootics in Iberia and N Africa spanning as they do, 5 or more yr, seem to have established a new pattern in AHS virus persistence. This is probably linked to the continuous presence of adult C imicola in the area. Culicoides imicola is basically an Afro-Asiatic insect and prefers warm climates. Therefore its continuous adult presence in parts of Iberia and N Africa may be due to some recent moderations of the climate in these areas.
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Forbes, A. B. (1993). A review of regional and temporal use of avermectins in cattle and horses worldwide. Vet Parasitol, 48(1-4), 19–28.
Abstract: Ivermectin and abamectin are two members of the group of parasiticides known as the avermectins; ivermectin was first registered as an injectable treatment for cattle in 1981. Since then, abamectin has been registered for cattle and ivermectin for horses. The relative popularity of the avermectins amongst farmers and veterinarians can be attributed to their spectrum of activity, convenience, wide margin of safety and the improved health and performance of stock following their use. Patterns of use in grazing animals apply equally to the avermectins as to other antiparasitics, particularly anthelmintics; these are based on a knowledge of epidemiology integrated with practical management considerations. For cattle, programs are commonly aimed at control of abomasal nematodes of the genera Ostertagia and Haemonchus. Use of avermectins is largely strategic in cattle, treatments being favored at the end of the period of transmission of these parasites; this frequently coincides with housing, entry into a feedlot or movement to another pasture. Simultaneous control of important ectoparasites at this time is an added benefit. Prophylactic use of avermectins at pasture is primarily targeted at the young first season grazing animal. In horses, a bimonthly treatment schedule during the period of risk has proved effective in helping prevent adverse effects of the main target parasites, including large and small strongyles and stomach bots. These patterns of use can be applied to the evaluation of the potential for avermectin residues in feces to have impact on pasture ecology. The evidence presented suggests that any effects are temporally and spatially limited. After more than a decade of practical use, there is no indication that avermectins have had a significant impact on pasture ecology and the environment.
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Capela, R., Sousa, C., Pena, I., & Caeiro, V. (1993). Preliminary note on the distribution and ecology of Culicoides imicola in Portugal. Med Vet Entomol, 7(1), 23–26.
Abstract: Data on Culicoides imicola were obtained during studies carried out during the recent outbreak of African horse sickness in Portugal. The previous most northerly published record of C. imicola in Portugal was 38 degrees 40'N (Pegoes). In the present work the geographical distribution of this species is extended to the parallel of 41 degrees 17'N. We have also confirmed the continuous presence of adult C. imicola in Southern Portugal (Alentejo and Algarve) throughout the year. In the laboratory we obtained this species from a sample of cattle faeces and from another of soil contaminated with animal excreta. In relation to host association 57.37% of C. imicola were trapped in the vicinity of pigsties. Finally, we collected 11,463 Culicoides of which 12.47% were C. imicola.
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Beveridge, W. I. (1993). Unravelling the ecology of influenza A virus. Hist Philos Life Sci, 15(1), 23–32.
Abstract: For 20 years after the influenza A virus was discovered in the early 1930s, it was believed to be almost exclusively a human virus. But in the 1950s closely related viruses were discovered in diseases of horses, pigs and birds. Subsequently influenza A viruses were found to occur frequently in many species of birds, particularly ducks, usually without causing disease. Researchers showed that human and animal strains can hybridise thus producing new strains. Such hybrids may be the cause of pandemics in man. Most pandemics have started in China or eastern Russia where many people are in intimate association with animals. This situation provides a breeding ground for new strains of influenza A virus.
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McGlone, J. J., & Hicks, T. A. (1993). Teaching standard agricultural practices that are known to be painful. J. Anim Sci., 71(4), 1071–1074.
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Heyes, C. M. (1993). Imitation, culture and cognition. Anim. Behav., 46(5), 999–1010.
Abstract: Abstract. This paper examines the significance of imitation in non-human animals with respect to the phylogenetic origins of culture and cognitive complexity. It is argued that both imitation (learning about behaviour through nonspecific observation) and social learning (learning about the environment through conspecific observation) can mediate social transmission of information, and that neither is likely to play an important role in supporting behavioural traditions or culture. Current evidence suggests that imitation is unlikely to do this because it does not insulate information from modification through individual learning in the retention period between acquisition and re-transmission. Although insignificant in relation to culture, imitation apparently involves complex and little-understood cognitive operations. It is unique in requiring animals spontaneously to equate extrinsic visual input with proprioceptive and/or kinaesthetic feedback from their own actions, but not in requiring or implicating self-consciousness, representation, metarepresentation or a capacity for goal-directed action.
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Mitchell R. (1993). Mental models of mirror self-recognition: two theories. New Ideas Psychol., 11, 211.
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Nagell K, Olguin RS, & Tomasello M. (1993). Processes of social learning in the tool use of chimpanzees (Pan troglodytes) and human children (Homo sapiens). J. Comp. Psychol., 107, 174.
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