Evaluating velvet antler growth in red deer stags (Cervus elaphus) using hand-held and digital infrared thermography

Abstract

S. 2010. Evaluating velvet antler growth in red deer stags (Cervus elaphus) using hand-held and digital infrared thermography. Can. J. Anim. Sci. 90: 13Á21. The objectives of this study were to evaluate whether velvet antler (VA) surface temperature gradients, as measured by either a single-spot infrared temperature (SST) sensor (SSTS; exp. 1) or digital infrared temperature (DIT) imaging (DITI; exp. 2), would pattern VA growth. In exp. 1, growth rates and SST were obtained from yearling (n 08) and mature (n 017) red deer stags (Cervus elaphus) every 14 d following eruption through day 56 in yearlings and day 112 in mature stags. In exp. 2, growth rates and DIT (main beam VA base, mid and tip temperatures) were obtained from red deer stags (n031) every 14 d following eruption through day 126. Background temperatures were recorded in conjunction with thermal antler measurements. In exp. 1, yearling VA base and tip SST were positively correlated with one another (PB0.01); however, both measurements were also positively correlated with background SST (PB0.05). In mature stags, VA base SST paralleled (PB0.05) background SST measures, while tip SST did not change from day 56 through day 112. In exp. 2, VA DIT changed (PB0.01) over time and differed (PB0.01) between base, mid and tip. During the early growth period, VA temperatures increased (PB0.05) from 38.990.28C at the base to 39.390.28C at the tip of the antler. In contrast, during the late growth period, DIT was higher (PB0.01) at the base (36.890.38C) than at the tip (35.790.38C) of the antler. In conclusion, SSTS did not have the sensitivity to signify changes in antler growth rates. However, in exp. 2 using DITI, VA thermogenesis paralleled VA growth suggesting that DITI may have value in monitoring VA growth.Key words: Velvet antler, red deer, thermography Bowers, S., Gandy, S., Dickerson, T., Brown, C., Strauch, T., Neuendorff, D., Randel, R. et Willard, S. 2010. É valuation de la croissance du bois de velours chez le wapiti maˆle (Cervus elaphus) au moyen d'un thermographe infrarouge manuel et nume´rique. Can. J. Anim. Sci. 90: 13Á21. L'e´tude devait e´tablir si le gradient de tempe´rature a`la surface du bois de velours (BV), e´tabli au moyen d'un capteur infrarouge mesurant ponctuellement la tempe´rature (CI, premie`re expe´rience) ou d'un dispositif d'imagerie nume´rique (DIN, deuxie`me expe´rience), permettrait d'analyser la croissance du BV. Lors de la premie`re expe´rience, les auteurs ont releve´le taux de croissance et la tempe´rature chez des wapitis (Cervus elaphus) d'un an (n 08) et adultes (n 017) tous les 14 jours, de l'e´ruption au 56 e jour pour les sujets d'un an et jusqu'au 112 e jour pour les adultes. Dans la deuxie`me expe´rience, ils ont de´termine´le taux de croissance et la tempe´rature (a`la base, au milieu et al 'extre´mite´du bois) sur des wapitis adultes (n 031) tous les 14 jours de l'e´ruption a`la 126 e journe´e. La tempe´rature de fond a e´te´enregistre´e avec celle du bois. Lors de la premie`re expe´rience, la tempe´rature du...

Thermography as a tool to monitor the velvet temperature and ossification stage of fallow deer (Dama dama) antlers under normal and modified photoperiodic conditions

“…The acquired thermograms were useful for the analysis of the stages and the rate of the antler growth and to predict the timing of the velvet shedding. Bowers et al (2010) relied on thermal imaging to analyse the growth of antlers in red deer, and reported results that are similar to our findings. The cited authors divided red deer stags into two age groups (younger than 2 years and older than 2 years) and conducted observations for 112 days.…”

“…The reported differences in the antler temperatures between the measurement points do not coincide with our findings. In the work of Bowers et al (2010), the average temperatures were around 0.03 °C higher at the mid-section of the beam than at the tip of the antlers, whereas, in our study of fallow deer, the corresponding differences were 1.5 °C on average. In the study, the temperature measured at the tip of the antlers in the second stage of antler growth (observation days 28 to 70) reached 38.4 °C and was identical to that determined at the midsection of the beam, whereas the temperature at the base was 37.9 °C.…”

“…In the last stage of antler growth (observation days 70 to 112), the average temperatures were determined at 36.8 °C at the base and 35.7 °C at the tip. Bowers et al (2010) performed the temperature measurements when the antlers were covered with velvet, and they did not investigate the velvet shedding from both beams. Our study analysed the velvet shedding period, which is an important stage in the antler growth cycle.…”

“…Each colour thermogram featured a thermal palette for analysing the distribution and variations in the temperature at different measurement points. Measurements were performed based on the methodology described by Bowers et al (2010) for examining red deer antlers, with certain modifications to account for the anatomical differences in the fallow deer.…”

The Practical Application Of 3D Vision in the Field: Measuring Reindeer (Rangifer Tarandus) Antler Growth Velocities

“…In addition to this fundamental pursuit, antler measurement is of considerable importance to other scientific investigations focused on determining the effects of systemic hormones and local growth factors (specifically insulin‐like growth factor) on antler growth (Park et al., ), determining the relationship between temperature and antler growth (Bowers et al., ), quantifying the variation of body mass and antler size with animal age and sex (Melnycky et al., ), and identifying the correlation between live weight and first antler development (Ward et al., ). Antler measurement also has several very practical applications with significant economic impact including the identification of sires for breeding (Ward et al., ) and the determination of optimal velvet harvest time (Bowers et al., ). In these and other studies, antler length is a key variable and measurements are typically made using a tape measure.…”