Development of a body condition scoring index for female African elephants validated by ultrasound measurements of subcutaneous fat.

Kari A Morfeld,Christina Alligood,Jeff Bolling,John Lehnhardt,Janine L Brown,James F.X Wellehan

doi:10.1371/journal.pone.0093802

Kari A Morfeld, Christina Alligood + Show 4 more

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https://doi.org/10.1371/journal.pone.0093802

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Abstract

Obesity-related health and reproductive problems may be contributing to non-sustainability of zoo African elephant (Loxodonta africana) populations. However, a major constraint in screening for obesity in elephants is lack of a practical method to accurately assess body fat. Body condition scoring (BCS) is the assessment of subcutaneous fat stores based on visual evaluation and provides an immediate appraisal of the degree of obesity of an individual. The objective of this study was to develop a visual BCS index for female African elephants and validate it using ultrasound measures of subcutaneous fat. To develop the index, standardized photographs were collected from zoo (n = 50) and free-ranging (n = 57) female African elephants for identifying key body regions and skeletal features, which were then used to visually determine body fat deposition patterns. This information was used to develop a visual BCS method consisting of a list of body regions and the physical criteria for assigning an overall score on a 5-point scale, with 1 representing the lowest and 5 representing the highest levels of body fat. Results showed that as BCS increased, ultrasound measures of subcutaneous fat thickness also increased (P<0.01), indicating the scores closely coincide with physical measures of fat reserves. The BCS index proved to be reliable and repeatable based on high intra- and inter-assessor agreement across three assessors. In comparing photographs of wild vs. captive African elephants, the median BCS in the free-ranging individuals (BCS = 3, range 1–5) was lower (P<0.001) than that of the zoo population (BCS = 4, range 2–5). In sum, we have developed the first validated BCS index for African elephants. This tool can be used to examine which factors impact body condition in zoo and free-ranging elephants, providing valuable information on how it affects health and reproductive potential of individual elephants.

Highlights

Efforts to maintain a self-sustaining population of African elephants (Loxodonta africana) in zoos have met with limited success [1], in part because of high mortality and low reproduction; over the past decade, there have been only three births to five deaths annually in the U.S [2]
A scatter plot of Body condition scoring (BCS) and mean ultrasound measurement of fat thickness for the five body regions is presented in Figure 5, which shows that the mean ultrasound measures of fat thickness increased as BCS increased
We have developed a new visual BCS index for assessing body fat and condition in female African elephants

Summary

Introduction

Efforts to maintain a self-sustaining population of African elephants (Loxodonta africana) in zoos have met with limited success [1], in part because of high mortality and low reproduction; over the past decade, there have been only three births to five deaths annually in the U.S [2]. If this trend continues, the captive population will pass through a bottleneck in 30 years, and could become demographically nonviable in about 50 years [2]. Circumstantial evidence suggests there may be a link between obesity-related changes and poor health and reproduction in elephants [5,6,12]

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