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© 2018 Elsevier Inc. Group housing provides horses with social contact, a lack of which is associated with health and behavior problems. Despite the benefits of group housing for horses, horse owners are concerned about aggression and resulting injuries. This study focused on agonistic and affiliative interactions in a focal group of (originally) 12 horses with short-term and longer term changes in composition, variation in available area, and presence of periparturient mares. Age and density had no significant effect on agonistic or affiliative behavior. However, when agonistic behavior was considered within 3 subcategories, density did have a significant positive effect on contact and threat aggression but not on passive aggression (avoid and displace). When analyzing only the days without the most aggressive horse, age and density had a positive effect on agonistic interactions, and density had a negative effect on affiliative interactions. Days with and without the most aggressive horse showed no significant overall differences in either category of social interactions. Agonistic and affiliative interactions were not significantly correlated, but agonistic interactions had a significant linear and quadratic effect on affiliative interactions. Relative level of aggressiveness was used instead of a formal measure of dominance rank as aggression level is the main issue for horse owners. Comparing interactions with more and less aggressive horses, there was no overall effect for affiliative interactions. However, overall, horses in the focal group were on average 3.7 times more aggressive toward less aggressive horses, compared to more aggressive horses. Relationships between agonistic and affiliative interactions, density, age, and the role of relative aggressiveness are complicated, and more research is needed to clarify the most relevant factors under particular sets of circumstances and their contribution to intraspecific aggression in various contexts. ispartof: JOURNAL OF VETERINARY BEHAVIOR-CLINICAL APPLICATIONS AND RESEARCH vol:29 pages:61-69 status: published

Dissertação de Mestrado Integrado em Medicina Veterinária Anthelmintic resistance (AHR) in gastrointestinal parasites of ruminants and horses has been continuously described all over the world in the last two decades. In order to delay, or even prevent, the further development of resistance to anthelmintics, a new deworming approach must be taken, considering the diagnostic tools available nowadays. This study aims to evidence the differential performances of four commonly employed coprological methods, using different flotation solutions, and make some practical recommendations on which technique seems better-suited to face this emerging problem in horse management. This thesis contains two parts. In the first one, three wild ungulate species were analyzed at ARTIS Amsterdam Royal Zoo to determine the repeatability of four common coprological methods – simple flotation (SF), centrifugal flotation (CF), McMaster (McM - sensitivity of 50 eggs per gram EPG) and Mini-FLOTAC (MF – sensitivity of 5 EPG) – in association with three flotation solutions with different specific gravities: salt (SG=1.20), magnesium sulphate (MgSO4) (SG=1.24) and sugar solution (SG=1.28); where each sample was analyzed 10 times. In the second part 17 fecal samples of Sorraia horses were collected in April 2019 (12 females on the pasture and five stabled males) and analyzed with the same methods but only with the salt and sugar solutions; each sample was analyzed in triplicates for SF and CF and in duplicates for McM and MF. As a semi-quantitative parameter, the number of eggs were counted in 10 fields of each slide and the mean was obtained for each replicate. In the first part of the study, CF was able to evidence a higher amount of total egg counts, especially with the denser solutions, with lower coefficients of variation (CV). MF performed with very good precision across the species, with different solutions apparently better for each one of them. In the second part of the study, SFsalt obtained the best results for detecting Triodontophorus spp. eggs, although not significantly (p>0.05). Yet, it showed lower CV than CF techniques, which makes it a more precise and reliable technique. High parasitic burdens (mean of 1825 EPG for all techniques) were registered and MFsugar performed more consistently as seen by its low variability. Through coprocultures, the prevalence of Cyathostomum s.l. type D (100%) and S. vulgaris (5.9%) were also detected. The results obtained here support the use of CF and MF methods in zoos as valid diagnostic tools. In general, MF was shown to be more precise and reliable across the study, urging the need to review current guidelines for the diagnosis of AHR, namely in horses. Unexpectedly, a clear association was evidenced, as salt solutions seem to be better suited for qualitative methods, whereas the sugar solutions better suited for quantitative ones instead. RESUMO - A resistência a anti-helmínticos (RAH) de parasitas gastrointestinais de ruminantes e cavalos tem sido largamente descrita em todo o mundo nas últimas duas décadas. De modo a atrasar, ou até prevenir, o seu desenvolvimento, uma nova abordagem à desparasitação destes animais deve ser feita, considerando as ferramentas de diagnóstico disponíveis atualmente. Este estudo tem como objetivo evidenciar os desempenhos diferenciais de quatro métodos coprológicos comummente empregados, usando diferentes soluções de flutuação, e fazer algumas recomendações práticas sobre qual a técnica que parece ser mais adequada para enfrentar este problema emergente no maneio de equinos. Esta tese divide-se em duas partes. Na primeira, três espécies de ungulados selvagens foram analisadas no ARTIS Amsterdam Royal Zoo para determinar a repetibilidade de quatro métodos coprológicos testados - flutuação simples (SF), flutuação com centrifugação (CF), McMaster (McM - sensibilidade de 50 ovos por grama OPG) e Mini-FLOTAC (MF - sensibilidade de 5 OPG) - em associação com três soluções de flutuação de diferente gravidade específica (GE): de sal (GE = 1,20), de sulfato de magnésio (MgSO4) (GE = 1,24) e de açucar (GE = 1,28) onde cada amostra foi analisada 10 vezes. Na segunda parte, foram colhidas 17 amostras fecais de equinos da raça Sorraia, em Abril de 2019 (12 fêmeas na pastagem e cinco machos estabulados), e analisadas com os mesmos métodos, mas apenas com as soluções de sal e açúcar. Cada amostra foi analisada em triplicado para SF e CF e em duplicado para McM e MF. Como parâmetro semi-quantitativo, o número de ovos foi contado em 10 campos de cada lâmina microscópica e a média foi obtida para cada réplica. Na primeira parte, a CF foi capaz de evidenciar maiores contagens totais com menores coeficientes de variação (CV), principalmente com as soluções densas. MF apresentou muito boa precisão em todas as espécies, com diferentes soluções aparentemente melhores para cada uma. Na segunda parte, o SFsal obteve os melhores resultados para a deteção de Triodontophorus spp., embora não significativos (p> 0,05). No entanto, teve um CV menor do que as de CF, o que a torna a técnica qualitativa mais precisa. Foram observadas altas cargas parasitárias (média de 1825 OPG para todas as técnicas) e MFaçúcar foi a técnica mais consistente pela sua baixa variabilidade. Através de coproculturas confirmou-se a presença e prevalência de Cyathostomum s.l. tipo D (100%) e S. vulgaris (5,9%). Os resultados obtidos aqui suportam o uso de CF e MF em parques zoológicos como ferramentas de diagnóstico válidas. Em suma, MF mostrou-se mais preciso em todo o estudo, exigindo a revisão das diretrizes atuais para o diagnóstico de RAH, nomeadamente em equídeos. Surpreendentemente, uma a solução de sal parece ser mais adequada para métodos qualitativos e a solução de açúcar mais adequada para os quantitativos. N/A