Pestivirus and alphaherpesvirus infections in Swedish reindeer (Rangifer tarandus tarandus L.).

Herding semi-domesticated reindeer has economic and social value for Sami people in the northern territories of Fennoscandia. However, with the intensification of reindeer husbandry, interspecies transmission of pathogens between reindeer and domestic animals may become a problem, especially for countries such as Sweden, Norway, and Finland where pestivirus and alphaherpesvirus have been eradicated in domestic ruminants. This study, which included 1158 Swedish reindeer, showed relatively high prevalence of antibodies against bovine viral diarrhoea virus (BVDV) (32%) and bovine herpesvirus-1 (BoHV-1) (53%). Adult animals were more often seropositive for BVDV and BoHV-1 (50% and 78%, respectively) than were calves (18 and 11%, respectively). While the seroprevalence of alphaherpesvirus was similar in different herding districts, pestivirus seropositivity was highest in the South and diminished towards the North of the Swedish reindeer herding area. High correlation of the seropositivity against both pathogens at both individual and herd levels may indicate possible mutual synergetic effects and may be explained by the immunosuppressive nature of the viruses. While alphaherpesvirus seroprevalence was probably related to putative cervid herpesvirus 2 (CvHV-2), the pestivirus infecting reindeer remains undefined. The virus neutralisation test of reindeer sera using different pestivirus strains, revealed higher titres against Border disease virus strains like 137/4 (BDV-1) and Reindeer-1 (BDV-2) than against BVDV-1. However, the virus was not identified by real time RT-PCR in any of the samples (n=276) from seronegative reindeers. The study showed that pestivirus and alphaherpesvirus infections are endemic in the Swedish reindeer population.

Seasonal development of circadian and short-term activity in captive reindeer, Rangifer tarandus L.

1. Locomotor activity in a group of ten captive reindeer (Rangifer tarandus L.) was recorded automatically during a 15-month period at the University of Ume\0a, Sweden (63\dg 49\t' N). The records were complemented by observations on activity and rumination in March, June, September and December. Artificial food was provided at lib. 2. Reindeer have a polyphasic activity pattern with bursts occurring during both day and night. The number of activity peaks varies from 4-6 in the winter with 6 h of daylight to 6-9 in the summer with continuous daylight. The increase in the number of activity peaks is brought about by a splitting of the evening activity peak, thereby creating an increasing number of peaks with gradually shorter frequencies. 3. Sunrise and sunset act as \lssetpoints\rs for activity, separating it into a diurnal and a nocturnal phase. Since diurnal activity predominates, the reindeer is essentially a diurnal animal. Increasing daylength causes diurnal activity to increase in a 1:1 fashion while the ratio of night length to nocturnal activity is close to 1:0.5. This causes the total amount of activity over 24 h to change with photoperiod. 4. Food consumption was about 30% lower in winter than in summer and varied in accordance with the changes in the activity pattern 5. The time spent ruminating between meals was longer in winter than in summer, thus the winter activity pattern consisted of relatively few activity periods and long periods of rumination, unlike the summer pattern which was made up of large numbers of activity peaks with a shorter rumination time. 6. Rumination showed a rhythmical pattern within the single resting period. Reindeer were found to perform one to several bouts of rumination, each lasting approximately 50 min. 7. It is concluded that the activity pattern and the amount of activity is regulated mainly by changes in light-dark conditions. Photoperiod is presumed to provide the proximate factor governing the seasonal variations of energy intake in reindeer.