Seasonal changes in energy expenditure, body temperature and activity patterns in llamas (Lama glama)

Alexander Riek,Lea Brinkmann,Martina Gerken,Catherine Hambly,Walter Arnold,Thomas Ruf,Matthias Gauly,John R Speakman,Jurcevic Perica

doi:10.1038/s41598-017-07946-7

Abstract

Mammals typically keep their body temperature (Tb) within a narrow limit with changing environmental conditions. There are indications that some wild ungulates can exhibit certain forms of energy saving mechanisms when ambient temperatures are low and/or food is scarce. Therefore, the aim of the study was to determine if the llama, one of the most extensively kept domestic livestock species, exhibits seasonal adjustment mechanisms in terms of energy expenditure, Tb and locomotion. For that purpose llamas (N = 7) were kept in a temperate habitat on pasture. Locomotor activity, Tb (measured in the rumen) and the location of each animal were recorded continuously for one year using a telemetry system. Daily energy expenditure was measured as field metabolic rate (FMR). FMR fluctuated considerably between seasons with the lowest values found in winter (17.48 ± 3.98 MJ d−1, 402 kJ kg−0.75 d−1) and the highest in summer (25.87 ± 3.88 MJ d−1, 586 kJ kg−0.75 d−1). Llamas adjusted their energy expenditure, Tb and locomotor activity according to season and also time of day. Thus, llamas seem to have maintained the ability to reduce their energy expenditure and adjust their Tb under adverse environmental conditions as has been reported for some wild ungulates.

Highlights

Endothermic mammals usually have to keep their body temperature (Tb) in a narrow limit of 37–39 °C with changing ambient temperatures (Ta)[1, 2], which comes at a high energetic cost
Our study is the first in a camelid that combines the doubly labelled water method for measuring daily energy expenditure (DEE) with a telemetry system measuring locomotion and Tb, as well as estimating the distances covered by GPS
Our study presents the first continuous long-term Tb and activity measurements in a South American camelid

Summary

Introduction

Endothermic mammals usually have to keep their body temperature (Tb) in a narrow limit of 37–39 °C with changing ambient temperatures (Ta)[1, 2], which comes at a high energetic cost. Recent studies revealed that some ungulates can decrease their metabolic rate and Tb to some degree and adjust their daily energy expenditure (DEE) according to season. In its native region of South America the llama is used as a wool and meat producer, and as a beast of burden. There are no studies investigating seasonal adjustment mechanisms with regard to energy expenditure and Tb in South American camelids. In this regard the llama is a particular well suited model animal because it is one of the most robust livestock species, which can be described as a primary population[19]

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