Assessing body condition in the platypus (Ornithorhynchus anatinus): a comparison of new and old methods
J. W. Macgregor A H , C. Holyoake A , S. Munks B C , J. H. Connolly D E , I. D. Robertson A , P. A. Fleming F , R. A. Lonsdale G and K. Warren AA College of Veterinary Medicine, School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.
B Tasmanian Forest Practices Authority, 30 Patrick Street, Hobart, Tas. 7000, Australia.
C School of Zoology, University of Tasmania, Private Bag 5, Hobart, Tas. 7001, Australia.
D School of Animal and Veterinary Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, NSW 2678, Australia.
E Graham Centre for Agricultural Innovation, An Alliance Between Charles Sturt University and NSW Department of Primary Industries, Pugsley Place, Wagga Wagga, NSW 2650, Australia.
F Environmental and Conservation Sciences, School of Veterinary and Life Sciences, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia.
G Diagnostic Veterinary Imaging, PO Box 1146, Bentley Delivery Centre, Bentley, WA 6983, Australia.
H Corresponding author. Email: platypusproject@hotmail.com
Australian Journal of Zoology 64(6) 421-429 https://doi.org/10.1071/ZO16071
Submitted: 2 February 2016 Accepted: 17 March 2017 Published: 2 May 2017
Abstract
Body condition is an important aspect of the health of any animal. The current standard method of body condition assessment in the platypus is the tail volume index (TVI). Although the tail is the largest repository of fat in the platypus, the reliability of TVI has not been adequately demonstrated. The aims of this study were, first to assess performance of the TVI, and second, to develop and evaluate performance of new techniques for routine field assessment of platypus body condition. Morphometric data were collected under anaesthesia from 137 adult wild platypuses (74 males, 63 females) captured in north-west Tasmania; ultrasound images of tail fat were also collected from 100 of these individuals (54 males, 46 females). Three new indices for platypus body condition were identified. An objective tail fat index (Relative Tail Fat Volume: RTFVTBL) was developed, based on cross-sectional area measurements taken from detailed ultrasound images compared with total body length (TBL). Two body condition indices intended for routine field use were developed – one based on body mass (mb) and bill width (BW) (Body Condition Index; BCIBW), and the other based on a single linear ultrasonographic measurement of tail fat depth and BW (Relative Fat Depth; RFDBW). Results indicated that RFDBW outperforms TVI as an index of platypus tail fat. Further work, however, is needed to determine the relationship between tail fat and total body fat in the platypus before conclusions can be drawn about the effectiveness of BCIBW as a body condition index.
References
Bohonak, A., and van der Linde, K. (2004). RMA: software for reduced major axis regression, Java version. Available at: http://www.kimvdlinde.com/professional/rma.htmlEmenheiser, J. C., Tait, R. G., Shackelford, S. D., Kuehn, L. A., Wheeler, T. L., Notter, D. R., and Lewis, R. M. (2014). Use of ultrasound scanning and body condition score to evaluate composition traits in mature beef cows. Journal of Animal Science 92, 3868–3877.
| Use of ultrasound scanning and body condition score to evaluate composition traits in mature beef cows.Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BC2cXhslSjtbnJ&md5=72c9cbc041fc1109f825835fc155d1c5CAS |
Grant, T. R., and Carrick, F. N. (1978). Some aspects of the ecology of the platypus, Ornithorhynchus anatinus, in the upper Shoalhaven River, New South Wales. Australian Zoologist 20, 181–199.
Green, A. J. (2001). Mass/length residuals: measures of body condition or generators of spurious results? Ecology 82, 1473–1483.
| Mass/length residuals: measures of body condition or generators of spurious results?Crossref | GoogleScholarGoogle Scholar |
Gust, N., and Griffiths, J. (2011). Platypus (Ornithorhynchus anatinus) body size, condition and population structure in Tasmanian river catchments: variability and potential mucormycosis impacts. Wildlife Research 38, 271–289.
| Platypus (Ornithorhynchus anatinus) body size, condition and population structure in Tasmanian river catchments: variability and potential mucormycosis impacts.Crossref | GoogleScholarGoogle Scholar |
Hulbert, A. J., and Grant, T. R. (1983). A seasonal study of body condition and water turnover in a free-living population of platypuses, Ornithorhynchus anatinus (Monotremata). Australian Journal of Zoology 31, 109–116.
| A seasonal study of body condition and water turnover in a free-living population of platypuses, Ornithorhynchus anatinus (Monotremata).Crossref | GoogleScholarGoogle Scholar |
Jakob, E. M., Marshall, S. D., and Uetz, G. W. (1996). Estimating fitness: a comparison of body condition indices. Oikos 77, 61–67.
| Estimating fitness: a comparison of body condition indices.Crossref | GoogleScholarGoogle Scholar |
Le Cren, E. D. (1951). The length–weight relationship and seasonal cycle in gonad weight and condition in the perch (Perca fluviatilis). Journal of Animal Ecology 20, 201–219.
| The length–weight relationship and seasonal cycle in gonad weight and condition in the perch (Perca fluviatilis).Crossref | GoogleScholarGoogle Scholar |
Macgregor, J. (2008). Investigation into the distribution and physical characteristics of the platypus (Ornithorhynchus anatinus), and the distribution and prevalence of mucormycosis, in northwest Tasmania. M.Sc. Thesis, Murdoch University, Perth.
Macgregor, J. W. (2015). Conservation of the platypus (Ornithorhynchus anatinus): development of a framework to assess the health of wild platypus populations. Ph.D. Thesis, Murdoch University, Perth.
Magowan, E., and McCann, M. E. E. (2006). A comparison of pig backfat measurements using ultrasonic and optical instruments. Livestock Science 103, 116–123.
| A comparison of pig backfat measurements using ultrasonic and optical instruments.Crossref | GoogleScholarGoogle Scholar |
Munks, S., Otley, H., Bethge, P., and Jackson, J. (2000). Reproduction, diet and daily energy expenditure of the platypus in a sub-alpine Tasmanian lake. Australian Mammalogy 21, 260–261.
Peig, J., and Green, A. J. (2009). New perspectives for estimating body condition from mass/length data: the scaled mass index as an alternative method. Oikos 118, 1883–1891.
| New perspectives for estimating body condition from mass/length data: the scaled mass index as an alternative method.Crossref | GoogleScholarGoogle Scholar |
Peig, J., and Green, A. J. (2010). The paradigm of body condition: a critical reappraisal of current methods based on mass and length. Functional Ecology 24, 1323–1332.
| The paradigm of body condition: a critical reappraisal of current methods based on mass and length.Crossref | GoogleScholarGoogle Scholar |
Schulte-Hostedde, A. I., Zinner, B., Millar, J. S., and Hickling, G. J. (2005). Restitution of mass–size residuals: validating body condition indices. Ecology 86, 155–163.
| Restitution of mass–size residuals: validating body condition indices.Crossref | GoogleScholarGoogle Scholar |
Temple-Smith, P. D. M. (1973). Seasonal breeding biology of the platypus, Ornithorhynchus anatinus (Shaw, 1799), with special reference to the male. Ph.D. Thesis, Australian National University, Canberra.
Viggers, K. L., Lindenmayer, D. B., Cunningham, R. B., and Donnelly, C. F. (1998). Estimating body condition in the mountain brushtail possum, Trichosurus caninus. Wildlife Research 25, 499–509.
| Estimating body condition in the mountain brushtail possum, Trichosurus caninus.Crossref | GoogleScholarGoogle Scholar |
