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Motivation to obtain a food reward of pregnant ewes in negative energy balance: Behavioural, metabolic and endocrine considerations

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dc.contributor.author Verbeek, Else
dc.contributor.author Waas, Joseph R.
dc.contributor.author Oliver, Mark Hope
dc.contributor.author McLeay, Lance M.
dc.contributor.author Ferguson, D.M.
dc.contributor.author Matthews, Lindsay R.
dc.date.accessioned 2012-10-02T02:19:34Z
dc.date.available 2012-10-02T02:19:34Z
dc.date.copyright 2012-07
dc.date.issued 2012
dc.identifier.citation Verbeek, E., Waas, J. R., Oliver, M. H., McLeay, L. M., Ferguson, D. M., & Matthews, L. R. (2012). Motivation to obtain a food reward of pregnant ewes in negative energy balance: Behavioural, metabolic and endocrine considerations. Hormones and Behavior, 62(2), 162-172. en_NZ
dc.identifier.issn 0018-506X
dc.identifier.uri http://hdl.handle.net/10289/6670
dc.description.abstract Low food availability often coincides with pregnancy in grazing animals. This study investigated how chronic reductions in food intake affected feeding motivation, and metabolic and endocrine parameters in pregnant sheep, which might be indicative of compromised welfare. Ewes with an initial Body Condition Score of 2.7 +/- 0.3 (BCS: 0 indicates emaciation and 5 obesity) were fed to attain low (LBC 2.0 +/- 0.0,), medium (MBC 2.9 +/- 0.1) or high BCS (HBC 3.7 +/- 0.1) in the first trimester of pregnancy. A feeding motivation test in which sheep were required to walk a set distance for a palatable food reward was conducted in the second trimester. LBC and MBC ewes consumed more rewards (P=0.001) and displayed a higher expenditure (P=0.02) than HBC ewes, LBC ewes also tended to consume more rewards than MBC ewes (P=0.09). Plasma leptin and glucose concentrations were inversely correlated to expenditure (both P<0.05) and appear to be associated with hunger in sheep. LBC ewes were in negative energy balance, with lower muscle dimensions, plasma glucose, leptin, insulin, cortisol, and insulin-like growth factor-1 concentrations and higher free fatty acids concentrations compared to HBC ewes; metabolic and endocrine parameters of the MBC ewes were intermediate. The high feeding motivation and negative energy balance of low BCS ewes suggested an increased risk of compromised welfare. Imposing even a small cost on a food reward reduced motivation substantially in high BCS ewes (despite high intake when food was freely available). Assessment of a willingness to work for rewards, combined with measures of key metabolic and endocrine parameters, may provide sensitive barometers of welfare in energetically-taxed animals. en_NZ
dc.language.iso en
dc.publisher Elsevier en_NZ
dc.relation.ispartof Hormones and Behavior
dc.subject Behavioural demand en_NZ
dc.subject Body condition score en_NZ
dc.subject Energy balance en_NZ
dc.subject Feeding motivation en_NZ
dc.subject Hunger en_NZ
dc.subject Leptin en_NZ
dc.subject Pregnancy en_NZ
dc.subject sheep en_NZ
dc.subject welfare en_NZ
dc.title Motivation to obtain a food reward of pregnant ewes in negative energy balance: Behavioural, metabolic and endocrine considerations en_NZ
dc.type Journal Article en_NZ
dc.identifier.doi 10.1016/j.yhbeh.2012.08.007 en_NZ


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