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Sufit, E., Houpt, K. A., & Sweeting, M. (1985). Physiological stimuli of thirst and drinking patterns in ponies. Equine Vet J, 17(1), 12–16.
Abstract: The stimuli that elicit thirst were studied in four ponies. Nineteen hours of water deprivation produced an increase in plasma protein from 67 +/- 0.1 g/litre to 72 +/- 2 g/litre, a mean (+/- se) increase in plasma sodium from 139 +/- 3 to 145 +/- 2 mmol/litre and an increase in plasma osmolality from 297 +/- 1 to 306 +/- 2 mosmol/litre. Undeprived ponies drank 1.5 +/- 0.9 kg/30 mins; 19 h deprived ponies drank 10.2 +/- 2.5 kg/30 mins and corrected the deficits in plasma protein, plasma sodium and plasma osmolality as well as compensating for the water they would have drunk during the deprivation period. In order to determine if an increase in plasma osmolality would stimulate thirst, 250 ml of 15 per cent sodium chloride was infused intravenously. The ponies drank when osmolality increased 3 per cent and when plasma sodium rose from 136 +/- 3 mmol/litre to 143 +/- 3 mmol/litre. Ponies infused with 15 per cent sodium chloride drank 2.9 +/- 0.7 kg; those infused with 0.9 per cent sodium chloride drank 0.7 +/- 0.5 kg. In order to determine if a decrease in plasma volume would stimulate thirst, ponies were injected with 1 or 2 mg/kg bodyweight (bwt) frusemide. Plasma protein rose from 68 +/- 2 g/litre pre-injection to 75 +/- 2 g/litre 1 h after 1 mg/kg bwt frusemide and to 81 +/- 1 g/litre 1 h after 2 mg/kg bwt frusemide.(ABSTRACT TRUNCATED AT 250 WORDS)
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Sweeting, M. P., Houpt, C. E., & Houpt, K. A. (1985). Social Facilitation of Feeding and Time Budgets in Stabled Ponies. J. Anim Sci., 60(2), 369–374.
Abstract: Eight pairs of pony mares were observed. Members of a pair were housed in adjacent stalls and fed hay ad libitum. The behavior of both ponies was recorded simultaneously in the morning (1000 to 1200 h) and afternoon (1400 to 1600 h) for a total of 117 h. The time budget was: 70.1 {+/-} 8.6% eating; 17.8 {+/-} 7.4% standing (including stand rest, stand alert and stand nonajert); 5.2 {+/-} 7.0% pushing hay; 2.9 {+/-} 1.2% walking; 1.9 {+/-} 2.9% drinking; 1.3 {+/-} 1.1% self-grooming; .2 {+/-} .3% defecating; .06 {+/-} .1% chewing nonfood items; .06 {+/-} .03% urination; .06 {+/-} .1% licking salt; .07 {+/-} .1% pawing hay; .6 {+/-} .7% lying and .07 {+/-} .08% stretching the neck over the stall wall dividing the ponies. While eating, the ponies lifted their heads 25.4 {+/-} 11.0 times/h. In less than one-half of the occasions when urination or defecation was observed, the ponies walked away from the spot where they had been eating to eliminate. During one-half of the observations, visual contact between the ponies was prevented by a solid partition between the stalls. The ponies spent significantly more time standing nonalert when the partition prevented visual contact (12 {+/-} 7%) than when visual contact could take place (6 {+/-} 3%, P<.05). When fresh hay was supplied in the mornings, the ponies spent similar amounts of time eating whether visual contact was allowed or not, but in the afternoon significantly more time was spent feeding when visual contact was allowed (73 {+/-} 4%) than when it was not (60 {+/-} 7%). Less time was spent eating, in the absence of visual contact, despite the presence of auditory and olfactory contact. Apparently social facilitation is important in maintaining feeding behavior in ponies. N1 -
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