Food intake may limit the ability of browsing mammals to gain body mass during the growing season when the leaves and stems of woody plants are most abundant. Moose are highly productive browsers with high demands for energy and nutrients, particularly during lactation. Using an indigestible marker, we estimated dry matter intake of free ranging adult female moose with and without calves over three growing seasons. During the same period, we analyzed forage quality. Intakes were highest in late spring (280 ± 19 g·kg-0.75·d-1) when forage quality peaked; however, intakes declined by 39% throughout the summer as temperatures increased and as acid detergent fiber content of browse increased. Digestibility of dry matter declined over summer from 71% to 57% among browse. Intakes were similar for moose with and without calves. Heat loads may impair the ability of moose to consume sufficient energy and nutrients. Warming and habitat change can adversely affect browser populations when poor forage qualities and low dry matter intakes combine to suppress digestible intakes of energy and nutrients.

Long-standing reports of open sores on the hind legs of moose (Alces alces) have been recorded in Alaska (as well as Canada, Europe, and Michigan), eliciting concerns about causes and infection. We used histological and genomic methods to investigate the sores from 20 adult moose on the Kenai Peninsula, Alaska. We paired this with thermal imagery and molt scoring of adult moose to further describe sore formation and understand its timing. Severe, ulcerative and eosinophilic dermatitis was found in all moose with sores present, and microfilariae within intraepidermal pustules were additionally found in four samples. Genetic analysis of sores from moose revealed a previously unknown genetic lineage of Onchocerca. Adult moose molt and lose their barrier of protection against flies in June and July during peak fly activity, leaving them vulnerable and allowing the development of sores. In summary, our results indicate that the cause for the sores on the hindleg of moose is a previously unknown genetic lineage of Onchocerca, probably transmitted by black flies, in timing with the molt cycle of adult moose. These sores leave moose exposed to pathogens, making them vulnerable, and challenging their health and fitness.

Background Timing of reproductive events can be crucial for a species’ population growth and stability. Accurate detection of reproductive phenology presents a challenge to scientists studying wild species, including moose (Alces alces). Currently, there are several established methods for monitoring reproductive activity and events in domestic ruminants, including the use of biologging devices. The main objective of this study was to determine whether female moose display a distinct thermal and activity pattern associated with luteal activity during the estrous cycle, which could be used to determine the onset of their breeding season. We deployed biologging devices and collected fecal samples from 12 captive female moose on the Kenai Peninsula, Alaska, USA to explore variation in vaginal temperature and collar activity and the relationship between these variables and fecal progestagen concentrations. Fecal samples were collected from mid-August to mid-October and analyzed using radioimmunoassay to determine the concentration of fecal progestagens to classify luteal activity. Results Captive female moose displayed an identifiable thermal pattern during the onset of luteal activity from mid-September to mid-October, associated with the initial estrous cycle of their breeding season. In contrast, we did not observe a distinct pattern in activity during this period. Recurring patterns in both vaginal temperature and activity were identified between mid-October and mid-November, however, which were likely associated with subsequent estrous cycles but not included in our fecal sampling period. Conclusions This study supports that female moose display an identifiable pattern in vaginal temperature which is associated with luteal activity of the initial estrous cycle of the breeding season. A clear, identifiable pattern was observed for both vaginal temperature and activity registrations at the presumed timing of subsequent estrous cycle of the breeding season.