title: Effects of season and body condition on appetite, body mass and body composition in ad libitum fed pony mares.
abstract: Changes in appetite, body mass (BM), body condition score (BCS), direct (ultrasonographic) and indirect (deuterium oxide dilution technique) measures of body fat were monitored in Welsh Mountain pony mares (n=11, 5-19 years of age) offered ad libitum access to a complete diet (gross energy 16.9±0.07 MJ/kg dry matter) for 12 weeks during summer (n=6; 246±20 kg) and winter (n=5; 219±21 kg). At the outset, each group comprised two thin (BCS 1-3/9), moderate (BCS 4-6/9) and obese (BCS 7-9/9) animals. For ponies that were non-obese at the outset, BM was gained more rapidly (P=0.001) in summer (0.8±0.1 kg/day) than winter (0.6±0.0 kg/day). This was associated with a seasonal increase in dry matter intake (DMI) which became maximal (summer, 4.6±0.3% BM as DMI/day; winter, 3.5±0.1% BM as DMI/day) during the second month. The appetite of the obese ponies was half that reported for non-obese animals in the summer and BM remained constant irrespective of season. Body 'fatness' increased progressively for non-obese but not obese ponies. Body fat content was exponentially associated with increasing BCS but BCSs >6 were not useful indicators of actual body fat. Endogenous circannual mechanisms to suppress winter weight gain were insufficient to prevent the development of obesity in ad libitum fed ponies.
authors.affiliation: University of Liverpool, School of Veterinary Science, Leahurst, Chester High Road, Neston, Wirral CH64 7TE, UK.
authors.forename: Alexandra H A
authors.initials: AH
authors.lastname: Dugdale
authors.forename: Gemma C
authors.initials: GC
authors.lastname: Curtis
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Cripps
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Harris
authors.forename: Caroline McG
authors.initials: CM
authors.lastname: Argo
mesh_terms: D000818:Animals; D001066:Appetite / Q000502:physiology*; D001823:Body Composition / Q000502:physiology; D001824:Body Constitution / Q000502:physiology*; D015992:Body Mass Index; D005248:Feeding Methods / Q000662:veterinary*; D005260:Female; D006736:Horses / Q000502:physiology*; D012621:Seasons