Linklater, W. L., Henderson, K. M., Cameron, E. Z., Stafford, K. J., & Minot, E. O. (2000). The robustness of faecal steroid determination for pregnancy testing Kaimanawa feral mares under field conditions. N Z Vet J, 48(4), 93–98.
Abstract: AIMS: To investigate the utility of faecal oestrone sulphate (OS) concentrations for detecting pregnancy in mares during behavioural studies of feral horses, in which the collection and preservation of samples is not immediate. METHODS: Oestrone sulphate concentrations were measured in fresh dung samples collected from 153 free-roaming Kaimanawa mares throughout the year. In addition, multiple samples were taken from the same pile to investigate the reliability of diagnosis from a single sample, as well as the influence of time until preservation on OS concentrations. Samples were also taken before and after a 10mm simulated rainfall event to test for dilution of OS concentrations by rain. Oestrone sulphate concentrations in all samples were measured using an enzyme immunoassay. RESULTS: From approximately 150 to 250 days of gestation, OS concentrations were consistently >80 ng/g in mares which subsequently foaled. Mares which did not foal and had low faecal OS concentrations in multiple samples throughout the year had faecal OS concentrations of 31+/-13 ng/g (mean+/-s.d.) with an upper 95% confidence limit of 57 ng/g. Mares sampled from 1 week before to 1 month after behavioural oestrus, and that did not foal in the previous and subsequent seasons, had OS concentrations of 37+/-32 ng/g (mean+/-s.d.) with an upper 95% confidence limit of 100 ng/g. The standard error of oestrone sulphate concentrations in multiple samples from the same dung pile ranged from 1 to 37% of the mean. This large within-pile variation, however, did not result in incorrect diagnoses from single samples unless mares were within 18 days of parturition. Keeping samples at ambient temperatures for up to 16 hours did not affect OS concentrations. Simulated rainfall caused a 17% mean reduction in OS concentrations, but did not change pregnancy diagnoses. CONCLUSIONS: Faecal OS concentrations >100 ng/g were indicative of pregnancy in Kaimanawa mares. For mares more than 150 days post-mating, OS concentrations <57 ng/g were indicative of non-pregnancy, while concentrations between 57 and 100 ng/g provided an inconclusive diagnosis. A single sample from each dung pile collected within 16 hours of defecation was sufficient to accurately diagnose pregnancy in mares 150-250 days post conception. CLINICAL RELEVANCE: Measurement of OS concentrations in dung samples was a reliable and robust indicator of pregnancy status in feral mares 150-250 days post mating. This corresponds approximately to the period from May to August, given the seasonal breeding pattern in this population. This method of determining pregnancy status is suitable for field use in behavioural and demographic studies of wild horse populations.
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Cooper, J. J., McDonald, L., & Mills, D. S. (2000). The effect of increasing visual horizons on stereotypic weaving: implications for the social housing of stabled horses. Appl Anim Behav Sci, 69(1), 67–83.
Abstract: Stabled horses commonly perform stereotypic patterns of weaving, where the horse shifts its weight from side to side often swinging its head. Ten warm-blood types, of which five were known to reliably weave, were housed in similar 12x12 ft wooden loose boxes in a single stable block surrounding a courtyard. Each horse was exposed to each of five stable designs. These were: the conventional front top-half of the door open only with a view of the stable courtyard (F); front half-door open and a similar half-door open at the back of the stable with a view to the surrounding fields (FB); back open only (B); front and one-side panel open with a view into the adjacent stable (FS); and front, back and both sides open (All4). During observation days, horses were brought in from the field at 0830 h, fed concentrate at 0930 h, fed haylage at 1005 h and turned out at 1600 h. Behaviour was recorded from 0900 to 1040 h, 1200 to 1300 h and 1500 to 1600 h. Weaving was most common prior to feeding in the morning and prior to putting out to pasture in the afternoon. There was a significant effect of stable design on weaving, with less weaving in the FS and All4 designs than the F treatment. There was also a significant effect of stable design on repetitive nodding, though in this case, FB, B, FS and All4 designs each reduced nodding compared with the F treatment. The effect of stable design can be explained in a number of ways. Firstly, it could be the novelty of the environmental change, though there was no evidence in this study of an increase in stereotypy with prolonged exposure to the new stable designs. Secondly, opening windows may increase opportunities for environmental interaction, and the expression of new activities may compete with stereotypic behaviour for the horse's time. Thirdly, the open windows may allow expression of specific activities such as environmental monitoring or social interaction that are denied by the conventional stable.
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Roels, S., Tilmant, K., Van Daele, A., Van Marck, E., & Ducatelle, R. (2000). Proliferation, DNA ploidy, p53 overexpression and nuclear DNA fragmentation in six equine melanocytic tumours. Journal of Veterinary Medicine, Series A, 47, 439–438.
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Hohmann, G., & Fruth, B. (2000). Use and function of genital contacts among female bonobos. Anim. Behav., 60(1), 107–120.
Abstract: Female bonobos, Pan paniscus, show a mounting behaviour that differs physically from that in other primate species. They embrace each other ventroventrally and rub their genital swellings against each other. We investigated five hypotheses on the function of ventroventral mounting (genital contacts) that derive from previous studies of both primate and nonprimate species: (1) reconciliation; (2) mate attraction; (3) tension regulation; (4) expression of social status; and (5) social bonding. We collected data in six field seasons (1993-1998) from members of a habituated, unprovisioned community of wild bonobos at Lomako, Democratic Republic of Congo. No single hypothesis could account for the use of genital contacts, which appeared to be multifunctional. We found support for hypotheses 1 and 3. Rates of postconflict genital contacts exceeded preconflict rates suggesting that the display is used in the context of reconciliation. Rates of genital contacts were high when food could be monopolized and tension was high. However, genital contacts also occurred independently of agonistic encounters. Our study shows rank-related asymmetries in initiation and performance of genital contacts supporting the social status hypothesis: low-ranking females solicited genital contacts more often than high-ranking females while the latter were more often mounter than mountee. Although subordinates took more initiative to achieve genital contact, dominants mostly responded to the solicitation (ventral presentation) with mounting, indicating that the performance benefits both individuals. We suggest that genital contacts can be used to investigate both quality and dynamics of dyadic social relationships among female bonobos. Copyright 2000 The Association for the Study of Animal Behaviour.
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Lanier, J. L., Grandin, T., Green, R. D., Avery, D., & McGee, K. (2000). The relationship between reaction to sudden, intermittent movements and sounds and temperament. J. Anim Sci., 78(6), 1467–1474.
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Olesen, I., Groen, A. F., & Gjerde, B. (2000). Definition of animal breeding goals for sustainable production systems. J. Anim Sci., 78(3), 570–582.
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Sprigge, T. L. S. (2000). Darwinian Dominion: Animal Welfare and Human Interests: Lewis Petrinovich, Cambridge, Mass, London, England, MIT Press, 1999, ix + 431 pages, {pound}31.50 (hc). J. Med. Ethics, 26(5), 412–.
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Bickerton, D. (2000). Resolving Discontinuity: A Minimalist Distinction between Human and Non-human Minds. Integr. Comp. Biol., 40(6), 862–873.
Abstract: Our genotype is so similar to those of the African apes, and our last common ancestor with them so recent, that it seems impossible that human and non-human cognition should differ qualitatively. But the outputs of human cognition are unique in their limitless creativity and adaptability. Exaption resolves the apparent paradox. Assume that the power to create symbols emerges from stimulus-stimulus linkages and is latent in many animals, and that the structural side of language emerges from the argument structures inherent in the social calculus associated with reciprocal altruism. These adaptations confer the potential for language. However, creating complex messages requires uniquely long-lasting coherence of neural signals, which depends in turn on the large quantities of neurons unique to Homo. The only difference between human and non-human minds is that we can sustain longer and more complex trains of thought. All else (emotions, rational processes, even consciousness) could be exactly the same.
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Forkman, B. (2000). Domestic hens have declarative representations. Anim. Cogn., 3(3), 135–137.
Abstract: It is generally considered that information can be stored either as a procedural or as a declarative representation. A devaluation technique was used to determine whether hens have declarative representations. Individual hens (Gallus gallus domesticus) were fed in an enclosure with two containers, each with a new food type. One of the food types was devalued by pre-feeding with that food, after which the hens were tested with empty food containers. The pre-feeding should only affect the choice of the hens if they have learned where a particular food type was (declarative representation) rather than “go left when coming into the enclosure” (procedural representation). A significant proportion of the hens went to the location previously occupied by the non-devalued food (seven out of eight). This supports the hypothesis that domestic hens can form declarative representations.
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Xia, L., Siemann, M., & Delius, J. D. (2000). Matching of numerical symbols with number of responses by pigeons. Anim. Cogn., 3(1), 35–43.
Abstract: Pigeons were trained to peck a certain number of times on a key that displayed one of several possible numerical symbols. The particular symbol displayed indicated the number of times that the key had to be pecked. The pigeons signalled the completion of the requirement by operating a separate key. They received a food reward for correct response sequences and time-out penalties for incorrect response sequences. In the first experiment nine pigeons learned to allocate 1, 2, 3 or 4 pecks to the corresponding numerosity symbols s1, s2, s3 and s4 with levels of accuracy well above chance. The second experiment explored the maximum set of numerosities that the pigeons were capable of handling concurrently. Six of the pigeons coped with an s1-s5 task and four pigeons even managed an s1-s6 task with performances that were significantly above chance. Analysis of response times suggested that the pigeons were mainly relying on a number-based rather than on a time-based strategy.
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