Gerken, Martina

[["dc.bibliographiccitation.firstpage","826"],["dc.bibliographiccitation.issue","3"],["dc.bibliographiccitation.journal","Research in Veterinary Science"],["dc.bibliographiccitation.lastpage","831"],["dc.bibliographiccitation.volume","94"],["dc.contributor.author","Brinkmann, Lea"],["dc.contributor.author","Gerken, Martina"],["dc.contributor.author","Riek, Alexander"],["dc.date.accessioned","2018-11-07T09:24:28Z"],["dc.date.available","2018-11-07T09:24:28Z"],["dc.date.issued","2013"],["dc.description.abstract","Outdoor group housing is increasingly recognized as an appropriate housing system for domesticated horses. The objective of this study was therefore to investigate the effect of potential feed shortage in semi-natural horse keeping systems in winter on animal health and welfare. In 10 female Shetland ponies blood concentrations (NEFA, total protein (TP), total bilirubin (TB), beta-hydroxybutyrate (BHB) and thyroxine (T-4)), body mass and the body condition score (BCS) were monitored for 7 months including a 4 months period of feed restriction in five of the 10 ponies. Restrictively fed animals lost 18.4 +/- 2.99% of their body mass and the BCS decreased by 2.2 +/- 0.8 points (BCS scale: 0 = emaciated, 5 = obese). Feed restriction led to a continuous increase in TB (P < 0.001) and NEFA (P < 0.01) concentrations compared to control ponies. The TP and BHB values only differed at the end of the trial with lower concentrations in restricted fed mares (P < 0.05). Feed restriction had no effect on thyroxine concentrations. TB concentrations in the feed restricted group were out of the reference range during the entire feeding trial. The increased NEFA concentrations in feed restricted compared to control ponies suggest that fat was mobilized. The BCS, as well as plasma NEFA and TB concentrations were good indicators for a rapid detection of possible health problems caused by undernourishment in horses when kept under semi-natural conditions. In contrast, blood parameters of the control animals were within the reference ranges, suggesting that a year round outdoor housing with additional feed supply is an adequate housing system for a robust horse breed like the Shetland pony. (C) 2012 Elsevier Ltd. All rights reserved."],["dc.identifier.doi","10.1016/j.rvsc.2012.10.010"],["dc.identifier.isi","000318380600078"],["dc.identifier.pmid","23141417"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29826"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Sci Ltd"],["dc.relation.issn","0034-5288"],["dc.title","Effect of long-term feed restriction on the health status and welfare of a robust horse breed, the Shetland pony (Equus ferus caballus)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","58"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Züchtungskunde"],["dc.bibliographiccitation.lastpage","73"],["dc.bibliographiccitation.volume","85"],["dc.contributor.author","Brinkmann, Lea"],["dc.contributor.author","Gerken, Martina"],["dc.contributor.author","Riek, Alexander"],["dc.date.accessioned","2018-11-07T09:31:03Z"],["dc.date.available","2018-11-07T09:31:03Z"],["dc.date.issued","2013"],["dc.description.abstract","The aim of this study was to detect adaptation mechanisms of a domesticated horse breed to seasonal changes in climatic conditions and food availability. Therefore 10 female Shetland ponies were held under semi-extensive outdoor conditions for one year. During the second winter period the animals were allocated into one control and one treatment group, whose amount of feed was reduced from 100% to 70% of the recommended maintenance requirements. Throughout the study period, ambient temperature, body mass, body condition score, resting heart rate, locomotor activity, subcutaneous temperature (Ts), rectal temperature and total water intake were recorded individually on a biweekly or monthly basis. The Shetland ponies adapted to seasonal climatic changes and reduced feed availability by lowering their body mass, body condition score, locomotor activity; resting heart rate, Ts and total water intake. The reduced locomotor activity; resting heart rates and Ts indicate a reduced metabolic rate in winter. Additionally the diurnal rhythm of locomotor activity and Ts suggest a daily reduction in metabolism. Our Shetland ponies showed an effective adaptation to changes in environmental conditions by changes in behaviour, physiological parameters and metabolism. We therefore conclude that domestication had little effect on the Shetland ponies' adjustment mechanisms in relation to environmental conditions, as our data show clear signs of a hypometabolism."],["dc.identifier.isi","000209450400008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31450"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Eugen Ulmer Gmbh Co"],["dc.relation.issn","1867-4518"],["dc.relation.issn","0044-5401"],["dc.title","Adaptation strategies of Shetland ponies (Equus ferus caballus) to seasonal changes in climatic conditions and food availability"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4320"],["dc.bibliographiccitation.issue","24"],["dc.bibliographiccitation.journal","Journal of Experimental Biology"],["dc.bibliographiccitation.lastpage","4327"],["dc.bibliographiccitation.volume","217"],["dc.contributor.author","Brinkmann, Lea"],["dc.contributor.author","Gerken, Martina"],["dc.contributor.author","Hambly, Catherine"],["dc.contributor.author","Speakman, John R."],["dc.contributor.author","Riek, Alexander"],["dc.date.accessioned","2018-11-07T09:32:00Z"],["dc.date.available","2018-11-07T09:32:00Z"],["dc.date.issued","2014"],["dc.description.abstract","Recent results suggest that wild Northern herbivores reduce their metabolism during times of low ambient temperature and food shortage in order to reduce their energetic needs. It is, however, not known whether domesticated animals are also able to reduce their energy expenditure. We exposed 10 Shetland pony mares to different environmental conditions (summer and winter) and to two food quantities (60% and 100% of maintenance energy requirement) during low winter temperatures to examine energetic and behavioural responses. In summer, ponies showed a considerably higher field metabolic rate (FMR; 63.4 +/- 15.0 MJ day(-1)) compared with food-restricted and control animals in winter (24.6 +/- 7.8 and 15.0 +/- 1.1 MJ day(-1), respectively). During summer, locomotor activity, resting heart rate and total water turnover were considerably elevated (P<0.001) compared with winter. Animals on a restricted diet (N=5) compensated for the decreased energy supply by reducing their FMR by 26% compared with control animals (N=5). Furthermore, resting heart rate, body mass and body condition score were lower (29.2 +/- 2.7 beats min(-1), 140 +/- 22 kg and 3.0 +/- 1.0 points, respectively) than in control animals (36.8 +/- 41 beats min(-1), 165 +/- 31 kg, 4.4 +/- 0.7 points; P<0.05). While the observed behaviour did not change, nocturnal hypothermia was elevated. We conclude that ponies acclimatize to different climatic conditions by changing their metabolic rate, behaviour and some physiological parameters. When exposed to energy challenges, ponies, like wild herbivores, exhibited hypometabolism and nocturnal hypothermia."],["dc.description.sponsorship","German Research Foundation (DFG) [GE 704/13-1]"],["dc.identifier.doi","10.1242/jeb.111815"],["dc.identifier.isi","000346420200012"],["dc.identifier.pmid","25359931"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31649"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Company Of Biologists Ltd"],["dc.relation.issn","1477-9145"],["dc.relation.issn","0022-0949"],["dc.title","Saving energy during hard times: energetic adaptations of Shetland pony mares"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","667"],["dc.bibliographiccitation.issue","12"],["dc.bibliographiccitation.journal","JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL GENETICS AND PHYSIOLOGY"],["dc.bibliographiccitation.lastpage","675"],["dc.bibliographiccitation.volume","307A"],["dc.contributor.author","Riek, Alexander"],["dc.contributor.author","van Der Sluijs, Leendert"],["dc.contributor.author","Gerken, Martina"],["dc.date.accessioned","2018-11-07T10:48:33Z"],["dc.date.available","2018-11-07T10:48:33Z"],["dc.date.issued","2007"],["dc.description.abstract","Energy expenditure and water flux were measured in free-ranging alpacas Lama pacos, a South American camelid, on natural pastures of the Peruvian Andes (altitude: 4,400 m above sea level). Water influx rate (WIR) was estimated in 16 males (age 2 years, weight 48.5 +/- 8.6 kg) labelled with (2)H. In addition, the field metabolic rate (FMR) was measured in four of these animals labelled with both an oxygen ((18)O) and a hydrogen ((2)H) isotope. The WIR averaged 3.62 L H(2)O/day and the mean total body water 33.1 kg, equal to 68.2% of body weight (BW). The FMR of the four doubly labelled animals was 14.05 MJ/day. New allometric equations were calculated describing the relationships between WIR or FMR and BW, respectively, including published data on ruminants and the present alpaca results. The regression equation indicates that daily WIR scales to a similar metabolic size (kilograms of BW(0.94)) in alpacas than in wild or domesticated ruminants and camelids originating from and and semiarid habitats. The resulting regression equation for FMR explained over 99% of the variation and corresponded to the function FMR (kilojoules per day) = 1079 (kilograms of BW(0.668)) (n = 5, r(2) = 0.995, P < 0.001). The FMR measured in this study, the first reported for a South American camelid species, suggests that free-ranging alpacas have similar energy expenditures on a metabolic weight basis as other wild ruminants living under harsh climatic conditions.."],["dc.identifier.doi","10.1002/jez.a.419"],["dc.identifier.isi","000250885600001"],["dc.identifier.pmid","17891750"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/48223"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.relation.issn","1932-5223"],["dc.title","Measuring the energy expenditure and water flux in free-ranging alpacas (Lama pacos) in the Peruvian Andes using the doubly labelled water technique"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1061"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Journal of Experimental Biology"],["dc.bibliographiccitation.lastpage","1068"],["dc.bibliographiccitation.volume","215"],["dc.contributor.author","Brinkmann, Lea"],["dc.contributor.author","Gerken, Martina"],["dc.contributor.author","Riek, Alexander"],["dc.date.accessioned","2018-11-07T09:12:04Z"],["dc.date.available","2018-11-07T09:12:04Z"],["dc.date.issued","2012"],["dc.description.abstract","Recent results suggest that the wild ancestor of the horse, the Przewalski horse, exhibits signs of a hypometabolism. However, there are speculations that domestic animals lost the ability to reduce energy expenditure during food shortage and adverse environmental conditions. Therefore, we investigated physiological and behavioural strategies employed by a robust domesticated horse breed, the Shetland pony, over the course of a year under temperate conditions by measuring ambient temperature (T-a), subcutaneous temperature (T-s), locomotor activity (LA), lying time, resting heart rate, body mass and body condition score. Ten animals were kept on pasture in summer and in open stables in winter; further, in winter the animals were allocated into one control and one feed-restricted group of five animals each to simulate natural seasonal food shortage. The annual course of the mean daily T-s of all horses showed distinct fluctuations from a mean of 35.6 +/- 0.5 degrees C, with higher variations in summer than in winter. Diurnal amplitudes in T-s were highest (P<0.001) in April (12.6 degrees C) and lowest in January (4.0 degrees C), with a nadir around dawn and a peak around mid-day. The feed-restricted group had a significantly lower daily T-s compared with the control group on cold winter days, with T-a values below 0 degrees C. Mean annual heart rate and LA followed T-a closely. Heart rate of the feed-restricted animals significantly decreased from a mean of 52.8 +/- 8.1. beats. min(-1) in summer to 29 +/- 3.9. beats. min(-1) in winter and differed from the control group (P<0.001). Mean daily LA was lowest at the end of winter (7000. activity impulses day(-1)) and highest in summer (25,000. activity. impulses. day(-1)). Our results show that Shetland ponies exhibit signs of a winter hypometabolism indicated by reduced heart rate and T-s. Thus, domesticated horses seem to have maintained the capacity for seasonal adaptation to environmental conditions by seasonal fluctuations in their metabolic rate."],["dc.identifier.doi","10.1242/jeb.064832"],["dc.identifier.isi","000301299500011"],["dc.identifier.pmid","22399650"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/26866"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Company Of Biologists Ltd"],["dc.relation.issn","0022-0949"],["dc.title","Adaptation strategies to seasonal changes in environmental conditions of a domesticated horse breed, the Shetland pony (Equus ferus caballus)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","120"],["dc.bibliographiccitation.journal","Research in Veterinary Science"],["dc.bibliographiccitation.lastpage","128"],["dc.bibliographiccitation.volume","129"],["dc.contributor.author","Runa, Rukhsana Amin"],["dc.contributor.author","Gerken, Martina"],["dc.contributor.author","Riek, Alexander"],["dc.contributor.author","Brinkmann, Lea"],["dc.date.accessioned","2020-12-10T15:21:08Z"],["dc.date.available","2020-12-10T15:21:08Z"],["dc.date.issued","2020"],["dc.identifier.doi","10.1016/j.rvsc.2019.12.014"],["dc.identifier.issn","0034-5288"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/72931"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Boer goats physiology adaptation to saline drinking water"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2559"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","Journal of Experimental Biology"],["dc.bibliographiccitation.lastpage","2566"],["dc.bibliographiccitation.volume","219"],["dc.contributor.author","Brinkmann, Lea"],["dc.contributor.author","Gerken, Martina"],["dc.contributor.author","Hambly, Catherine"],["dc.contributor.author","Speakman, John R."],["dc.contributor.author","Riek, Alexander"],["dc.date.accessioned","2018-11-07T10:10:09Z"],["dc.date.available","2018-11-07T10:10:09Z"],["dc.date.issued","2016"],["dc.description.abstract","During winter, free-living herbivores are often exposed to reduced energy supply at the same time that energy needs for thermoregulation increase. Several wild herbivores as well as robust horse breeds reduce their metabolism during times of low ambient temperature and food shortage. Thyroid hormones (THs) affect metabolic intensity and a positive effect of THs on basal metabolic rate (BMR) has been demonstrated in mammals and birds. As BMR and field metabolic rate (FMR) are often assumed to be intrinsically linked, THs may represent a reliable indicator for FMR. To test this hypothesis, 10 Shetland pony mares were kept under semi-extensive central European conditions. During the winter season, one group was fed 60% and one group 100% of their maintenance energy requirements. We measured FMR, locomotor activity, resting heart rate and TH levels in summer and winter. FMR, locomotor activity, resting heart rate and total T-3 concentrations decreased substantially in winter compared with summer, whereas total T-4 increased. Food restriction led to a reduced FMR and resting heart rate, while THs and locomotor activity were not affected. Across both seasons, FMR, resting heart rate and locomotor activity were positively correlated with total T-3 but negatively and more weakly correlated with total T-4."],["dc.description.sponsorship","German Research Foundation (DFG) [GE 704/13-1]"],["dc.identifier.doi","10.1242/jeb.138784"],["dc.identifier.isi","000381708300024"],["dc.identifier.pmid","27312472"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/39800"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Company Of Biologists Ltd"],["dc.relation.issn","1477-9145"],["dc.relation.issn","0022-0949"],["dc.title","Thyroid hormones correlate with field metabolic rate in ponies, Equus ferus caballus"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]