Abstract: The intake of a 2.0% sodium saccharin solution in rats was observed to increase as a function of both the number (Experiment 1) and the duration (Experiment 3) of prior periods of access to the saccharin flavor, but did not increase when subjects were maintained on a fluid deprivation procedure in the absence of saccharin exposure (Experiment 2). The enhancement of intake was further influenced by the schedule of saccharin preexposures in the absence of variations in the amount of solution tasted (Experiment 4). The effect was not a function of the opportunity for subjects to determine their own pattern of contact with the saccharin flavor, the opportunity for association of the flavor with hunger and thirst reduction, or the amount of saccharin swallowed during preexposure (Experiment 5). These results suggest that mere exposure to a flavored solution is sufficient to increase subsequent intakes. The phenomenon is discussed in terms of the attenuation of neophobia elicited by the novelty of flavored solutions.

Abstract: Administration of lithium chloride disrupted the intake of flavored solutions but not water in rats. This intake suppression was directly related to the amount of lithium administered (Experiment 1), occurred with both palatable and unpalatable novel saccharin solutions (Experiment 2), but was only observed if subjects were tested starting less than 75 min. after lithium treatment (Experiment 3). Twenty-five daily exposures to saccharin did not attenuate the effect (Experiment 4). However, in saccharin-reared and vinegar-reared rats, lithium did not disrupt consumption of the solutions these subjects had access to throughout life, even though suppressions of intake were observed when these subjects were tested with novel flavors (Experiment 5). The selective disruption of drinking is interpreted as a novelty-dependent sensitization reaction to the discomfort of aversive drug administration.

Abstract: This study investigated three methods of water supply on drinking preference and behavior in six Standardbred geldings (2-9 years, 505+/-9 kg). The water sources were buckets (B), pressure valve (PV), and float valve (FV) bowls. In an initial drinking preference test, PV was tested at three flow rates: 3, 8, and 16 l/min (PV3, PV8, and PV16), and FV at 3 l/min (FV3). Water intake was measured in l and presented as the percentage of the total daily water intake from each of two simultaneously presented alternatives. The intake from PV8 was greater than from both PV3 (72+/-11% vs. 28+/-11%) and PV16 (90+/-4% vs. 10+/-4%). All horses showed a strong preference for B, 98+/-1% of the intake compared to 2+/-1% from PV8. Individual variation in the data gave no significant difference in preference between the two automatic bowls. In the second part of the study, drinking behavior and fluid balance were investigated when the horses drank from FV3, PV8, and B for 7 consecutive days in a changeover design. Despite a tendency for an increase in total daily drinking time from FV3, the daily water intake was significantly lower (43+/-3 ml/kg) than from PV8 (54+/-2 ml/kg) and B (58+/-3 ml/kg). Daily net water gain [intake-(fecal+urinary output)] was only 0.5+/-3 ml/kg with FV3, resulting in a negative fluid balance if insensible losses are included. These results show that the water supply method can affect both drinking behavior and fluid balance in the horse.

Abstract: The feeding and drinking behavior of 11 mares and 15 foals living on pasture with free access to water was recorded during 2,340 15-min focal samples taken over 2 yr. Lactating mares on pasture spent about 70% of the day feeding. Foals began feeding on their first day of life. As they grew older, they spent progressively more time feeding, but still spent only 47 +/- 6% of the time feeding by 21 wk of age. Foals fed primarily during the early morning and evening. While grass formed the major proportion of the diet of both foals and mares, they also ate clay, humus, feces, bark, leaves and twigs. Almost all feeding by foals was done while their mothers were feeding. Movement to water sources was frequently, but not invariably, carried out by an entire herd. Frequency (P = .005) but not duration (P greater than .05) of drinking bouts by mares increased as the temperature increased. Frequency was greatest at 30 to 35 C, at which temperature mares drank once every 1.8 h. Frequency of drinking varied with the time of day (P less than .01), being rarest during the early morning (0500 to 0900 h eastern daylight time) and most frequent during the afternoon (1300 to 1700 h). Drinking by foals was very rare. The youngest age at which a foal was observed to drink was 3 wk, and 8 of 15 foals were never observed to drink before weaning.