Home << 1 2 3 4 >>
List View
 | 
Citations
 | 
Details
   web
Records
Author Khalil, A.M.; Murakami, N.; Kaseda, Y.
Title Relationship between plasma testosterone concentrations and age, breeding season and harem size in Misaki feral horses Type Journal Article
Year 1998 Publication The Journal of veterinary medical science / the Japanese Society of Veterinary Science Abbreviated Journal J Vet Med Sci
Volume 60 Issue 5 Pages 643-645
Keywords Age Factors; Animals; Animals, Wild; *Horses; Japan; Male; Reproduction; Seasons; Sexual Behavior, Animal; Sexual Maturation; *Social Behavior; Testosterone/*blood
Abstract Jugular vein blood samples were collected from 23 young and sexual mature feral stallions to examine the relationship between plasma testosterone concentration and age, breeding season or harem size. Testosterone concentration increased with the age of the stallions until they formed their own harems, at about 4 to 6 years old. Seasonal variations in testosterone concentrations were observed, and found to be significantly higher (P<0.001) throughout the breeding season than non-breeding season, from 3 years of age. Testosterone levels were correlated with harem size for individual stallions. It can be inferred from these results that there is a relationship between plasma testosterone concentration and age, breeding season and harem size.
Address Laboratory of Animal Behavioral Science, Faculty of Agriculture, Miyazaki University, Japan
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0916-7250 ISBN Medium
Area Expedition Conference
Notes PMID:9637303 Approved no
Call Number refbase @ user @ Serial (up) 137
Permanent link to this record
 
 
Author Kirkpatrick, J.F.; Turner, A.
Title Absence of effects from immunocontraception on seasonal birth patterns and foal survival among barrier island wild horses Type Journal Article
Year 2003 Publication Journal of applied animal welfare science : JAAWS Abbreviated Journal J Appl Anim Welf Sci
Volume 6 Issue 4 Pages 301-308
Keywords Animals; Animals, Newborn; Animals, Wild/*physiology; Birth Rate; Case-Control Studies; Contraception, Immunologic/methods/*veterinary; Egg Proteins/administration & dosage; Female; Horses/*physiology; Maryland/epidemiology; Membrane Glycoproteins/administration & dosage; Population Control; Pregnancy; *Receptors, Cell Surface; *Reproduction; Seasons; Vaccines, Contraceptive/administration & dosage
Abstract Despite a large body of safety data, concern exists that porcine zonae pellucidae (PZP) immunocontraception--used to manage wild horse populations--may cause out-of-season births with resulting foal mortality. Our study at Assateague, Maryland indicated the effects of immunocontraception on season of birth and foal survival between 1990 and 2002 on wild horses from Assateague Island. Among 91 mares never treated, 69 (75.8%) of foals were born in April, May, and June (in season). Among 77 treated mares, 50 (64.9%) were born in season. Of 29 mares foaling within 1 year after treatment (contraceptive failures), 20 (68.9%) were born in season. Of 48 mares treated for greater than 2 years then withdrawn from treatment, 30 (62.5%) of 48 foals were born in season. There were no significant differences (p <.05) between either treatment group or untreated mares. Survival did not differ significantly among foals born in or out of season or among foals born to treated or untreated mares. Data indicate a lack of effect of PZP contraception on season of birth or foal survival on barrier island habitats.
Address Science and Conservation Center Zoo Montana, Billings, Montana 59106, USA. jkirkpatrick@montana.net
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1088-8705 ISBN Medium
Area Expedition Conference
Notes PMID:14965784 Approved no
Call Number refbase @ user @ Serial (up) 140
Permanent link to this record
 
 
Author Cameron, E.Z.
Title Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism Type Journal Article
Year 2004 Publication Proceedings. Biological sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 271 Issue 1549 Pages 1723-1728
Keywords Age Factors; Animals; Body Constitution; *Evolution; Female; Glucose/metabolism/physiology; Litter Size; Male; Mammals/*physiology; *Models, Biological; Reproduction/physiology; Seasons; Sex Factors; *Sex Ratio; Time Factors
Abstract Evolutionary theory predicts that mothers of different condition should adjust the birth sex ratio of their offspring in relation to future reproductive benefits. Published studies addressing variation in mammalian sex ratios have produced surprisingly contradictory results. Explaining the source of such variation has been a challenge for sex-ratio theory, not least because no mechanism for sex-ratio adjustment is known. I conducted a meta-analysis of previous mammalian sex-ratio studies to determine if there are any overall patterns in sex-ratio variation. The contradictory nature of previous results was confirmed. However, studies that investigated indices of condition around conception show almost unanimous support for the prediction that mothers in good condition bias their litters towards sons. Recent research on the role of glucose in reproductive functioning have shown that excess glucose favours the development of male blastocysts, providing a potential mechanism for sex-ratio variation in relation to maternal condition around conception. Furthermore, many of the conflicting results from studies on sex-ratio adjustment would be explained if glucose levels in utero during early cell division contributed to the determination of offspring sex ratios.
Address Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa. ezcameron@zoology.up.ac.za
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0962-8452 ISBN Medium
Area Expedition Conference
Notes PMID:15306293 Approved no
Call Number refbase @ user @ Serial (up) 413
Permanent link to this record
 
 
Author Amdam, G.V.; Csondes, A.; Fondrk, M.K.; Page, R.E.J.
Title Complex social behaviour derived from maternal reproductive traits Type Journal Article
Year 2006 Publication Nature Abbreviated Journal Nature
Volume 439 Issue 7072 Pages 76-78
Keywords Aging/physiology; Animals; Bees/*physiology; *Evolution; Feeding Behavior/*physiology; Female; Infertility, Female; Maternal Behavior/*physiology; Ovary/physiology; Pollen/metabolism; Reproduction/*physiology; *Social Behavior
Abstract A fundamental goal of sociobiology is to explain how complex social behaviour evolves, especially in social insects, the exemplars of social living. Although still the subject of much controversy, recent theoretical explanations have focused on the evolutionary origins of worker behaviour (assistance from daughters that remain in the nest and help their mother to reproduce) through expression of maternal care behaviour towards siblings. A key prediction of this evolutionary model is that traits involved in maternal care have been co-opted through heterochronous expression of maternal genes to result in sib-care, the hallmark of highly evolved social life in insects. A coupling of maternal behaviour to reproductive status evolved in solitary insects, and was a ready substrate for the evolution of worker-containing societies. Here we show that division of foraging labour among worker honey bees (Apis mellifera) is linked to the reproductive status of facultatively sterile females. We thereby identify the evolutionary origin of a widely expressed social-insect behavioural syndrome, and provide a direct demonstration of how variation in maternal reproductive traits gives rise to complex social behaviour in non-reproductive helpers.
Address Arizona State University, School of Life Sciences, Tempe, Arizona 85287, USA. Gro.Amdam@asu.edu
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1476-4687 ISBN Medium
Area Expedition Conference
Notes PMID:16397498 Approved no
Call Number refbase @ user @ Serial (up) 531
Permanent link to this record
 
 
Author Dunbar, R.
Title Evolution of the social brain Type Journal Article
Year 2003 Publication Science Abbreviated Journal Science
Volume 302 Issue 5648 Pages 1160-1161
Keywords Animals; Animals, Wild; *Cognition; Endorphins/physiology; *Evolution; Female; Grooming; Hierarchy, Social; Language; Neocortex/anatomy & histology/physiology; Papio/physiology/*psychology; *Reproduction; *Social Behavior; Social Dominance; Social Support; Vocalization, Animal
Abstract
Address School of Biological Sciences, University of Liverpool, Liverpool L69 7ZB, UK. rimd@liv.ac.uk
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1095-9203 ISBN Medium
Area Expedition Conference
Notes PMID:14615522 Approved no
Call Number refbase @ user @ Serial (up) 548
Permanent link to this record
 
 
Author Moehlman, P.D.
Title Endangered wild equids Type Journal Article
Year 2005 Publication Scientific American Abbreviated Journal Sci Am
Volume 292 Issue 3 Pages 74-81
Keywords Africa; Americas; Animals; *Animals, Wild/physiology; Asia; *Conservation of Energy Resources; Environment; *Equidae/physiology; Food Chain; Humans; Male; Reproduction
Abstract
Address IUCN-The World Conservation Union/Species Survival Commission Equid Specialist Group
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0036-8733 ISBN Medium
Area Expedition Conference
Notes PMID:15859216 Approved no
Call Number refbase @ user @ Serial (up) 551
Permanent link to this record
 
 
Author Keiper, R.; Houpt, K.
Title Reproduction in feral horses: an eight-year study Type Journal Article
Year 1984 Publication American journal of veterinary research Abbreviated Journal Am J Vet Res
Volume 45 Issue 5 Pages 991-995
Keywords Abortion, Veterinary/epidemiology; Anestrus; Animal Population Groups/*physiology; Animals; Animals, Wild/*physiology; Birth Rate; Female; Fertility; Horse Diseases/epidemiology; Horses/*physiology; Lactation; Male; Maryland; Pregnancy; *Reproduction; Seasons; Sex Ratio; Virginia
Abstract The reproductive rate and foal survival of the free-ranging ponies on Assateague Island National Seashore were studied for 8 years, 1975 to 1982. Most (52%) of the 86 foals were born in May, 13% were born in April, 22.6% in June, 10.4% in July, and less than 1% in August and September. The mean foaling rate was 57.1 +/- 3.9% and the survival rate was 88.3 +/- 3.6%. Forty-eight colts and 55 fillies were born (sex ratio 53% female). Mares less than 3 years old did not foal and the foaling rate of 3-year-old mares was only 23%, that of 4-year-old mares was 46%, that of 5-year-old mares was 53%, and 6-year-old mares was 69%. The relatively poor reproduction rate was believed to be a consequence of the stress of lactating while carrying a foal when forage quality on the island was low. The hypothesis was supported by the higher reproductive rate (74.4 +/- 2.4%) of the ponies in the Chincoteague National Wildlife Refuge on the southern part of the island. Their foals are weaned and sold in July each year. Despite the low reproductive rate on Assateague Island National Seashore , the number of ponies increased from 43 to 80, a 90% increase in the 8-year period or greater than 10%/yr. There were 24 deaths and 8 dispersals from the study area.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0002-9645 ISBN Medium
Area Expedition Conference
Notes PMID:6732036 Approved no
Call Number refbase @ user @ Serial (up) 665
Permanent link to this record
 
 
Author Collery, L.
Title Observations of equine animals under farm and feral conditions Type Journal Article
Year 1974 Publication Equine veterinary journal Abbreviated Journal Equine Vet J
Volume 6 Issue 4 Pages 170-173
Keywords Aggression; Animals; Animals, Newborn; Breeding; Circadian Rhythm; Feeding Behavior; Female; Horses/*physiology; Housing, Animal; Humans; Male; Pregnancy; Puberty; Reproduction; Sexual Behavior, Animal; Social Dominance
Abstract
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0425-1644 ISBN Medium
Area Expedition Conference
Notes PMID:4473340 Approved no
Call Number refbase @ user @ Serial (up) 680
Permanent link to this record
 
 
Author Westlin-van Aarde, L.M.; van Aarde, R. J.; Skinner, J. D.
Title Reproduction in female Hartmann's zebra Type Journal Article
Year 1988 Publication Journal of Reproduction and Fertility Abbreviated Journal J Reprod Fert
Volume 84 Issue Pages 505-511
Keywords zebra; reproduction; ovaries; seasonality; progesterone
Abstract Ovaries, fetuses and plasma were collected from zebra mares shot in the Etosha National Park in Namibia between 15 and 25 August 1983. Ovarian weight was affected by reproductive status and most of the non-pregnant mares were anoestrous. The number of follicles varied between individuals and only pro-oestrous/oestrous mares had follicles larger than 20 mm in diameter. The largest follicle in pregnant mares was only 9 mm in diameter. Corpora lutea and corpora albicantia were found in non-pregnant as well as pregnant mares: 4 pregnant mares had only corpora albicantia. The presence of secondary corpora lutea could not be confirmed in any of the pregnant mares. Implantation was estimated to occur at around 73 days of gestation, and most mares (84%) had conceived between November and April. Peripheral concentrations of plasma progesterone during pregnancy varied from 0·5 to 2·4 ng/ml.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes from Professor Hans Klingels Equine Reference List Approved yes
Call Number Serial (up) 1705
Permanent link to this record
 
 
Author Arnold, W.; Ruf, T.; Kuntz, R.
Title Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure Type Journal Article
Year 2006 Publication The Journal of experimental biology Abbreviated Journal J Exp Biol
Volume 209 Issue Pt 22 Pages 4566-4573
Keywords Animals; Animals, Wild/*physiology; Body Temperature; Body Temperature Regulation; Eating; *Energy Metabolism; Female; Heart Rate; Horses/*physiology; Male; Motor Activity; Pregnancy; Reproduction; *Seasons
Abstract Many large mammals show pronounced seasonal fluctuations of metabolic rate (MR). It has been argued, based on studies in ruminants, that this variation merely results from different levels of locomotor activity (LA), and heat increment of feeding (HI). However, a recent study in red deer (Cervus elaphus) identified a previously unknown mechanism in ungulates--nocturnal hypometabolism--that contributed significantly to reduced energy expenditure, mainly during late winter. The relative contribution of these different mechanisms to seasonal adjustments of MR is still unknown, however. Therefore, in the study presented here we quantified for the first time the independent contribution of thermoregulation, LA and HI to heart rate (f(H)) as a measure of MR in a free-roaming large ungulate, the Przewalski horse or Takhi (Equus ferus przewalskii Poljakow). f(H) varied periodically throughout the year with a twofold increase from a mean of 44 beats min(-1) during December and January to a spring peak of 89 beats min(-1) at the beginning of May. LA increased from 23% per day during December and January to a mean level of 53% per day during May, and declined again thereafter. Daily mean subcutaneous body temperature (T(s)) declined continuously during winter and reached a nadir at the beginning of April (annual range was 5.8 degrees C), well after the annual low of air temperature and LA. Lower T(s) during winter contributed considerably to the reduction in f(H). In addition to thermoregulation, f(H) was affected by reproduction, LA, HI and unexplained seasonal variation, presumably reflecting to some degree changes in organ mass. The observed phase relations of seasonal changes indicate that energy expenditure was not a consequence of energy uptake but is under endogenous control, preparing the organism well in advance of seasonal energetic demands.
Address Research Institute of Wildlife Ecology, University of Veterinary Medicine, Vienna, Savoyenstrasse 1, 1160 Vienna, Austria. walter.arnold@vu-wien.ac.at
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-0949 ISBN Medium
Area Expedition Conference
Notes PMID:17079726 Approved no
Call Number Serial (up) 1782
Permanent link to this record