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Author (up) Mitchell, D.; Allen, W. R.
Title Observations on reproductive performance in the yearling mare Type Journal Article
Year 1975 Publication Journal of Reproduction and Fertility Abbreviated Journal J. Reprod. Fert.,
Volume (Suppl. 23) Issue Pages 531-536
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Abstract Reproductive performance was studied in 137 yearling mares run with stallions in small groups for 3 months between June and August in 1968 to 1971 (four breeding seasons). Pregnancy diagnosis by repeated rectal palpation and qualitative tests for PMSG, showed that ninety-five mares conceived of which forty-four aborted spontaneously between days 30 and 160 of gestation. Laboratory examination of twenty-one aborted fetuses failed to show any infectious agents. Serial quantitative and qualitative tests for PMSG in aborting animals gave results similar to those observed in mares with normal pregnancies. Plasma progestagen assays showed marked individual variations although the loss of the conceptus was always associated with a drop in progestagen level. The high incidence of early pregnancy loss in these pubertal mares may also be related to immaturity, inadequate nutrition and physical stress.
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Call Number Equine Behaviour @ team @ Serial 2378
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Author (up) Mitchell, D.; Kirschbaum, E.H.; Perry, R.L.
Title Effects of neophobia and habituation on the poison-induced avoidance of exteroceptive stimuli in the rat Type Journal Article
Year 1975 Publication Journal of Experimental Psychology. Animal Behavior Processes Abbreviated Journal J Exp Psychol Anim Behav Process
Volume 1 Issue 1 Pages 47-55
Keywords Animals; Avoidance Learning/*drug effects; *Awareness; *Cognition; Conditioning, Operant; Feeding Behavior/drug effects; *Habituation, Psychophysiologic; Injections, Intraperitoneal; Lithium/administration & dosage/poisoning; Male; Rats; *Taste; Time Factors; *Visual Perception
Abstract Two experiments on the role of neophobia in poison-induced aversions to exteroceptive stimuli are reported. In Experiment 1, rats were given either 10 or 25 days of habituation to the test situation prior to conditioning. Those animals with the longer habituation period avoided a complex of novel exteroceptive stimuli while those with the shorter habituation period did not. In Experiment 2 rats initially avoided the more novel of two containers, but gradually came to eat equal amounts from both. A single pairing of toxicosis with consumption from either the novel or the familiar container reinstated the avoidance of the novel container in both cases. The results were discussed in terms of an interaction between habituation and conditioning procedures. It was suggested that previously reported differences between interoceptive and exteroceptive conditioning effects may have been influenced by the differential novelty of the two classes of stimuli in the test situation. It was further suggested that non-contingently poisoned control groups should routinely be included in poison avoidance conditioning studies.
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ISSN 0097-7403 ISBN Medium
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Notes PMID:1151289 Approved no
Call Number Equine Behaviour @ team @ Serial 2791
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