Abstract

Topic: Physiology, diseases and genetics

Trampe the moose calf - causes of disease and death in moose calves in Norway

Bjørnar Ytrehus¹, Emma E. Oterholt Aakre², Mari Mangen², Torunn Sjåheim², Han Kristian Mjelde³, Jørn Våge³, Malin Rokseth Reiten³

Norwegian Veterinary Institute, Postboks 64 (Arboretveien 57), NO
Norwegian University of Life Sciences
Norwegian Veterinary Institute

Abstract
Reports from the field and moose statistics indicate that the number of moose calves is in decline in Norway and that the calves still present show poor growth. The trend is most obvious in the southern parts of the country, and in these areas many hunters and managers suggest that the development may be associated with increased exposure to diseases. In 2024, we started a program called Elgkalven Trampe (Trampe the Moose Calf) were dedicated field contacts went out in the field and investigated cases where calves were found severely diseased and euthanised or found dead. The aim was to facilitate thorough examination and diagnosis of cause of disease/death. The hypothesis is that the state of the moose calves is a result of an interplay of multiple factors. Three mechanisms are focussed on: 1) Heat stress, 2) Phenological mismatch and 3) Increased disease load. In 2024 we examined or got samples from 63 calves. The most prevalent finding was that the calves were small and emaciated. Many of these were infected with opportunistic bacteriae and many had clostridial bacteriae present in the circulation. Anaplasma phagocytophilum was found in almost all of the cases. Nearly half of the calves were infected with Giardia duodenalis. Based on the findings from the first year of this study, it seems plausible that poor energy/protein uptake is an important factor, and it is suspected that poor nutritional status cause a poor immune response and predisposes to several infections. None of the mentioned mechanisms are rejected, but the preliminary evidence indicate that the situation not is caused by a single disease alone, but a result of multiple factors acting together.