Growth of moose calves (Alces alces americana) infested and uninfested with winter ticks (Dermacentor albipictus)

Abstract

Captive moose calves (Alces alces americana) in Algonquin Provincial Park, Ontario, were similar in size to most calves of the same age from other regions and of other subspecies. Their general patterns of growth were comparable to those observed for other northern cervids with an active growth phase throughout the summer and early autumn followed by a period of slow growth in winter. Maximum average daily mass gains (1.1 kg) were achieved in mid-September and were similar to those observed in other studies. Male calves were larger than females at any given age but males and females showed similar growth rates. Infestation with winter ticks (Dermacentor albipictus) may have caused a reduction in the mass gain of moose in autumn. If this occurs in the wild, heavy autumn tick infestation may predispose calves to reduced physical fitness and likelihood of survival during winter. Total length, chest girth, and shoulder height were all strongly correlated with live mass and may be valuable for estimating the live mass of moose calves under field conditions.