| Records |
| Author |
Linklater, W.L.; Cameron, E.Z. |
Title  |
Tests for cooperative behaviour between stallions |
Type |
Journal Article |
| Year |
2000 |
Publication |
Animal Behaviour. |
Abbreviated Journal |
Anim. Behav. |
| Volume |
60 |
Issue |
6 |
Pages |
731-743 |
| Keywords |
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| Abstract |
Breeding groups with multiple stallions occur sympatrically with single-stallion breeding groups in feral horse, Equus caballus, populations. Mutualism and reciprocal altruism between stallions have been proposed to explain the origin and functioning of multistallion bands. However, empirical support for these hypotheses is contradictory and incomplete. Furthermore, there are no explicit tests of the predictions that each hypothesis makes about stallion behaviour and social structure. We compared nine multistallion and 18 single-stallion bands in the Kaimanawa Ranges, New Zealand. Compared with agonistic behaviours, affiliative behaviours were relatively unimportant in the relationships between stallions within bands. The number of stallions in the band did not have a positive influence on mare group size, stability, home range quality or reproductive success in bands. Furthermore, there was a positive relationship between aggression ('intolerance') by the dominant towards subordinate stallions and the subordinates' effort in mare group defence ('helping') but a negative relationship between helping effort by subordinates and their proximity to, and mating with, the bands' mares. Therefore, the predictions of the mutualism and reciprocal altruism hypotheses were not supported. Indeed, for some of the predictions we found the opposite outcomes to be true. Multistallion bands had significantly poorer reproductive success, and dominant stallions were less tolerant of subordinates that helped most and reduced their access to mares. Nevertheless, in all other respects Kaimanawa stallions in multistallion bands behaved like those described elsewhere. Thus, we reject cooperative hypotheses for multimale breeding groups in horses and discuss the mate parasitism and consort hypotheses as better alternatives. Copyright 2000 The Association for the Study of Animal Behaviour. |
| Address |
Ecology Group, Institute of Natural Resources, Massey University |
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Place of Publication |
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| Language |
English |
Summary Language |
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Original Title |
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Edition |
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| ISSN |
0003-3472 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:11124871 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
415 |
| Permanent link to this record |
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| Author |
Linklater, W.L.; Henderson, K.M.; Cameron, E.Z.; Stafford, K.J.; Minot, E.O. |
| Title |
The robustness of faecal steroid determination for pregnancy testing Kaimanawa feral mares under field conditions |
Type |
Journal Article |
| Year |
2000 |
Publication |
New Zealand veterinary journal |
Abbreviated Journal |
N Z Vet J |
| Volume |
48 |
Issue |
4 |
Pages |
93-98 |
| Keywords |
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| Abstract |
AIMS: To investigate the utility of faecal oestrone sulphate (OS) concentrations for detecting pregnancy in mares during behavioural studies of feral horses, in which the collection and preservation of samples is not immediate. METHODS: Oestrone sulphate concentrations were measured in fresh dung samples collected from 153 free-roaming Kaimanawa mares throughout the year. In addition, multiple samples were taken from the same pile to investigate the reliability of diagnosis from a single sample, as well as the influence of time until preservation on OS concentrations. Samples were also taken before and after a 10mm simulated rainfall event to test for dilution of OS concentrations by rain. Oestrone sulphate concentrations in all samples were measured using an enzyme immunoassay. RESULTS: From approximately 150 to 250 days of gestation, OS concentrations were consistently >80 ng/g in mares which subsequently foaled. Mares which did not foal and had low faecal OS concentrations in multiple samples throughout the year had faecal OS concentrations of 31+/-13 ng/g (mean+/-s.d.) with an upper 95% confidence limit of 57 ng/g. Mares sampled from 1 week before to 1 month after behavioural oestrus, and that did not foal in the previous and subsequent seasons, had OS concentrations of 37+/-32 ng/g (mean+/-s.d.) with an upper 95% confidence limit of 100 ng/g. The standard error of oestrone sulphate concentrations in multiple samples from the same dung pile ranged from 1 to 37% of the mean. This large within-pile variation, however, did not result in incorrect diagnoses from single samples unless mares were within 18 days of parturition. Keeping samples at ambient temperatures for up to 16 hours did not affect OS concentrations. Simulated rainfall caused a 17% mean reduction in OS concentrations, but did not change pregnancy diagnoses. CONCLUSIONS: Faecal OS concentrations >100 ng/g were indicative of pregnancy in Kaimanawa mares. For mares more than 150 days post-mating, OS concentrations <57 ng/g were indicative of non-pregnancy, while concentrations between 57 and 100 ng/g provided an inconclusive diagnosis. A single sample from each dung pile collected within 16 hours of defecation was sufficient to accurately diagnose pregnancy in mares 150-250 days post conception. CLINICAL RELEVANCE: Measurement of OS concentrations in dung samples was a reliable and robust indicator of pregnancy status in feral mares 150-250 days post mating. This corresponds approximately to the period from May to August, given the seasonal breeding pattern in this population. This method of determining pregnancy status is suitable for field use in behavioural and demographic studies of wild horse populations. |
| Address |
Ecology Group, Institute of Natural Resources, Massey University, Private Bag 11-222, Palmerston North, New Zealand. wlinklater@hotmail.com |
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| Language |
English |
Summary Language |
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Original Title |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
0048-0169 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
PMID:16032132 |
Approved |
no |
| Call Number |
refbase @ user @ |
Serial |
411 |
| Permanent link to this record |
