Effect of varying initial drink volume on rehydration of horses

Validity of a behavioural measure of heat stress and a skin tent test for dehydration in working horses and donkeys

“…The equine thirst mechanism is stimulated by plasma hypertonicity (Butudom 2003) and, among donkeys in this study, higher serum osmolality correlated with both a shorter latency to first drink and a larger volume of water drunk. However, plasma may be hypo-or isotonic in animals producing hyper-or iso-osmolar sweat during exercise, and hypotonic in animals with chronic electrolyte depletion due to malnutrition or long-term sweat losses, and therefore drinking behaviour may not be a good indicator of dehydration.…”

Validity of indicators of dehydration in working horses: A longitudinal study of changes in skin tent duration, mucous membrane dryness and drinking behaviour

“…Figure 2 shows that P osm (with Na + and Cl -) fell by 8 ± 1.2 mOsm/l after the first drinking bout and maintained a steady state until 300 min. This agreed with findings by Butudom et al (2003) who observed P osm and Na + returning to normal within 30 min of rehydration of horses by offering water to drink. For the current investigation, P osm was selected as the criterion against which to test the validity of other parameters, although, as discussed by Bland and Altman (1999), this does not imply that it was a perfect measure.…”

“…The pattern of drinking behaviour, illustrated in Figure 1, shows that animals appeared to quench their thirst immediately on being offered water and their intake remained low for the rest of the study period. This agrees with Butudom et al (2003) who observed that following a 45 km endurance exercise test, horses drank as soon as water was offered and consumed the majority of their intake within 1-2 min. Houpt et al (1989) found that resting ponies deprived of water for 24 h also drank to satiety within 90 s of gaining access to water, often in a single long draught, and their fluid deficits were corrected precisely within 15 min.…”

“…Guidelines for subjective clinical assessment of dehydration vary considerably both between and within current equine veterinary textbooks (Barton and Moore 1999;Rose and Hodgson 2000;Robinson 2003). Butudom et al (2003) noted that sweat losses following exercise in the horse may be isotonic or hypertonic to plasma (potentially leading to isotonic or hypotonic dehydration) and that dehydration results partly from a mismatch between thirst and water deficit. A primary stimulus for thirst is plasma hypertonicity (Johnson 1998); this may be interpreted to suggest that voluntary water intake may not be a useful indicator of hydration status.…”

Parâmetros fisiológicos do desempenho de cavalos de alta performance hidratados voluntariamente com água ou solução isotônica contendo carboidrato

“…Os valores referentes às médias do 25,27,30,38,39 . Quanto às médias finais das concentrações séricas dos íons potássio e cálcio observam-se decréscimo nos resultados finais, quando comparadas com as do início da atividade física (Tabela 3).…”