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Author Turner, J.W.J.; Kirkpatrick, J.F.
Title Androgens, behaviour and fertility control in feral stallions Type Journal Article
Year 1982 Publication Journal of reproduction and fertility. Supplement Abbreviated Journal J Reprod Fertil Suppl
Volume (down) 32 Issue Pages 79-87
Keywords Animals; Animals, Wild; Copulation/drug effects; Female; *Fertility/drug effects; Horses/*physiology; Male; Periodicity; Pregnancy; Seasons; *Sexual Behavior, Animal/drug effects; Sexual Maturation; Sperm Count; Sperm Motility/drug effects; Testosterone/*blood/pharmacology
Abstract This field study of feral stallions in Montana and Idaho examines and correlates the seasonal pattern of plasma androgens and specific sociosexual behaviour and reports the effect of a long-acting androgenic steroid on this behaviour and on fertility. Plasma testosterone was measured by competitive protein binding assay in samples obtained by jugular venepuncture from captured animals. In samples taken from 34 sexually mature stallions in 6 different months during the year, a definite seasonal pattern in testosterone was present, with a peak in May (3.04 +/- 0.63 ng/ml) and a nadir in December (1.55 +/- 0.34 ng/ml). Values were less than 2.0 ng/ml in non-breeding months and greater than 2.4 ng/ml in breeding months. Behavioural endpoints measured were (1) stallion scent marking in response to elimination by mares (elimination marking), (2) mounting and (3) copulation. The frequencies of each of these endpoints followed closely the seasonal pattern seen for plasma androgens. In the fertility study microcapsulated testosterone propionate (microTP) was administered i.m. to 10 harem stud stallions 3 months before the 1980 breeding season. In these stallions and in 10 control harem studs, the above behavioural endpoints were examined in the 1980 and 1981 breeding seasons, and foal counts were made in 1981. There were no direct inhibitory or stimulatory effects of microTP treatment on any of the behavioural endpoints in either year. In 1981 foals were produced in 87.5% of the control bands and 28.4% of the microTP-treated bands. These results indicate that microencapsulated testosterone propionate can provide effective fertility control in feral horses without causing significant alterations in sociosexual behaviour.
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0449-3087 ISBN Medium
Area Expedition Conference
Notes PMID:6962905 Approved no
Call Number refbase @ user @ Serial 138
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Author Kirkpatrick, J.F.; Vail, R.; Devous, S.; Schwend, S.; Baker, C.B.; Wiesner, L.
Title Diurnal variation of plasma testosterone in wild stallions Type Journal Article
Year 1976 Publication Biology of reproduction Abbreviated Journal Biol Reprod
Volume (down) 15 Issue 1 Pages 98-101
Keywords Animals; *Circadian Rhythm; Horses/*blood; Male; Montana; Sexual Behavior, Animal; Species Specificity; Testosterone/*blood
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-3363 ISBN Medium
Area Expedition Conference
Notes PMID:986195 Approved no
Call Number refbase @ user @ Serial 149
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Author Andrew, R.J.
Title Changes in visual responsiveness following intercollicular lesions and their effects on avoidance and attack Type Journal Article
Year 1974 Publication Brain, Behavior and Evolution Abbreviated Journal Brain Behav Evol
Volume (down) 10 Issue 4-5 Pages 400-424
Keywords Animals; Chickens; Humans; Male; Mutism; Superior Colliculi/*physiology; Tectum Mesencephali; Testosterone; Visual Fields; Vocalization, Animal
Abstract In the normal chick, conspicuous visual stimuli induce targetting and pecking together, with vocalization. All three are abolished by lesion of the intercollicular area (ICo) or of connections passing through its medial margin. After such lesions, chicks also cease to treat significant visual stimuli as if they were startling and exciting, and may delay response as a result. However, they are still able to recognise, orient accurately to, and respond appropriately to, a variety of complex visual stimuli (e.g. food grains, copulation object). In addition, they are little affected by strange surroundings. Lesion evidence suggests the mammalian subcollicular area to have similar functions to the ICo and to be homologous with it. A route (present in bird), which is well-known in mammals for its association with threat, defense and escape evoked by strange and frightening objects (amygdala-diencephalic periventricular system-central mesencephalic grey, A-DPS-CMG) is stimuli via the 2 ICo (subcollicular area). Two different mechanisms may be involved caudal to the ICo. One consists of tectal afferents which might modulate the evocation of targetting, pecking and other responses via the tectum. The other is the predorsal system of tectal efferents which may mediate such responses. Classical syndromes of tameness and unresponsiveness produced by various interruptions of the A-DPS-CMG route may depend on interruption of connections to these midbrain mechanisms. Attack is depressed by ICo lesions as one aspect of reduced responsiveness to conspicuous and startling visual stimuli. Avoidance, which is apparently mediated by a separate system, much as in Anura, is facilitated.
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0006-8977 ISBN Medium
Area Expedition Conference
Notes PMID:1169102 Approved no
Call Number Equine Behaviour @ team @ Serial 4626
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