Applied Animal Behaviour Science, 15 (1986) 103--111 103 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands NIGHT-TIME BEHAVIOR OF STABLED AND PASTURED PERI-PARTURIENT PONIES KATHERINE A. HOUPT, MICHAEL F. O'CONNELL, THOMAS A. HOUPT and DENISE A. CARBONARO Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca, NY 14853 (U.S.A.) Department of Biology, Ithaca College, Ithaca, NY 14850 (U.S.A.) (Accepted for publication 28 February 1985) ABSTRACT Houpt, K.A., O'Connell, M.F., Houpt, T.A. and Carbonaro, D.A., 1986. Night-time be- havior of stabled and pastured peri-parturient ponies. Appl. Anita. Behav. Sci., 15: 103--111. Pregnant and lactating pony mares were observed in two environments, stable and pasture. Twenty-six pony mares were observed on pasture for 2 weeks before and after parturition. The behavior of each mare was recorded every 30 min from 18.00 to 06.00 h. The mutually exclusive behaviors were standing (either standing alert or standing at rest with a hindlimb flexed), grazing (prehending or masticating grass), walking, lying in sternal recumbency and lying in lateral recumbency. The total time-budget for pre- partum mares on pasture was 55.3 + 4.1% grazing, 32.9 + 3.3% standing, 6.0 ~ 1.5% lying in sternal recumbency, 2.7 ± 0.7% walking and 1.4 ± 0.6% lying in lateral recumbency. Grazing and standing occurred at all times, but grazing was most common from 18.00 to 21.00 h and after 05.00 h. Lying was most common between 01.00 and 04.00. Lying in lateral recumbency occurred only after dark, in pre-partum mares. The total time-budget for post-partum mares on pasture was 68.6 +_ 4.0% grazing, 22.5 + 3.0% standing, 4.7 -+ 1.0% walking, 4.2 + 1.2% lying in sternal recumbency and 0.2 ± 0.2% lying in lateral recumbency. Lying in lateral recumbency was seen only at 18.00 h. Lying in sternal recumbency occurred between 21.00 and 04.30 h. More time was spent grazing by the post-partum mares than by the pre-partum mares. The same behaviors were recorded for stabled pony mares except that eating hay rather than grazing constituted the ingestive behavior quantified. The total time-budget for pregnant stabled ponies was 71 + 3% standing, 15 ± 3% eating, 0.5 + 0% lying in lateral recumbency, 0.5 ± 0.2% walking and 12.1 ± 2.3% lying in sternal recumbency. Eating decreased and standing increased during the night. Most lying was seen between 01.30 and 05.00 h. Lying in lateral recumbency occurred between 19.30 and 03.30 h. The total nocturnal time-budget of post-partum stalled ponies was 67 ± 3% eating, 19 _+ 3% standing and 13.0 ± 2.3% lying in sternal recumbency. Post-partum mares were not observed to walk or to lie in lateral recumbency. The change in behavior after parturition may reflect: (1) nutritional demands of lacta- tion; (2) maternal protective behavior; (3) response to seasonal changes in the environ- ment. 0168-1591/86/$03.50 © 1986 Elsevier Science Publishers B.V.