Modern reindeer dairy farming—the influence of different milking regimes on udder health, milk yield and composition

Seroprevalence of Hepatitis E Virus in Moose (Alces alces), Reindeer (Rangifer tarandus), Red Deer (Cervus elaphus), Roe Deer (Capreolus capreolus), and Muskoxen (Ovibos moschatus) from Norway

Hepatitis E virus (HEV), a major cause of viral hepatitis worldwide, is considered an emerging foodborne zoonosis in Europe. Pigs (Sus scrofa domestica) and wild boars (S. scrofa) are recognized as important HEV reservoirs. Additionally, HEV infection and exposure have been described in cervids. In Norway, HEV has been identified in pigs and humans; however, little is known regarding its presence in wild ungulates in the country. We used a species-independent double-antigen sandwich ELISA to detect antibodies against HEV in the sera of 715 wild ungulates from Norway, including 164 moose (Alces alces), 186 wild Eurasian tundra reindeer (Rangifer tarandus tarandus), 177 red deer (Cervus elaphus), 86 European roe deer (Capreolus capreolus), and 102 muskoxen (Ovibos moschatus). The overall seroprevalence was 12.3% (88/715). Wild reindeer had the highest seropositivity (23.1%, 43/186), followed by moose (19.5%, 32/164), muskoxen (5.9%, 6/102), and red deer (4%, 7/177). All roe deer were negative. According to our results, HEV is circulating in wild ungulates in Norway. The high seroprevalence observed in wild reindeer and moose indicates that these species may be potential reservoirs of HEV. To the authors’ knowledge, this is the first report of HEV exposure in reindeer from Europe and in muskoxen worldwide.

Transfer of (85)Sr and (134)Cs from diet to reindeer foetuses and milk

Sr-85 and (134)Cs in aqueous solution of the chlorides were administered daily to four pregnant reindeer during the last part of gestation. Radionuclide concentrations were determined in calves sacrificed at birth, and secretion of the nuclides was measured in milk. Although the gastrointestinal absorption of (85)Sr was low, an apparently higher transfer of the absorbed fraction of (85)Sr than (134)Cs from the mother to the foetus led to similar accumulation of (85)Sr and (134)Cs in foetuses. At birth 1.4-1.6 and 1.5-2.5% of the total administered activities of (85)Sr and (134)Cs, respectively, were present in the calves' bodies. Transfer coefficients (F (m)) for (85)Sr and (134)Cs from feed to milk were estimated at 0.0218+/-0.0026 and 0.185+/-0.025 day kg(-1), respectively, and the observed ratio (OR(milk-diet)) for (85)Sr was 0.124+/-0.037. Transfer of radiostrontium to reindeer milk was in agreement with previously reported relationships between Ca intake and radiostrontium transfer in ruminants. These relationships suggest that the transfer of radiostrontium to foetuses and milk of free-ranging reindeer can be 3-4 times higher than observed in this experiment (due to lower Ca intake with natural forage), but the transfer to milk will not be as high as that of ionic (134)Cs. The concentrations of (85)Sr in milk suggested that the does mobilized skeletal stores of Ca and (85)Sr for milk production, although the diet appeared to satisfy the Ca requirements. In reindeer with radiostrontium intake during the whole year, radiostrontium concentrations in milk will therefore be higher than indicated by the F (m) value observed in our study. No differences in half-times for (85)Sr and (134)Cs secretion in milk were detected. Both nuclides were secreted with short- and long-term half-times of 1-2 and 12-19 days, respectively. For (85)Sr, 80-90% of the activity was excreted with the short half-time, whereas the corresponding value for (134)Cs was 30-50%.

Milk production and composition in reindeer (Rangifer tarandus): effect of lactational stage

Milk yield and composition of major milk constituents were measured in captive, nursing reindeer. Registration of milk production was performed during two successive lactations (2001 and 2002). The milk yield was significantly affected by week of lactation (P<0.001) and by individual (P<0.001). The lactation curve had an asymmetrical peak 3 weeks postpartum and the milk yield at peak lactation was 983 g/day (range 595-1239). The length of lactation varied from 24 to 26 weeks and average total milk production was 99.5 kg. From peak lactation the milk production decreased linearly (P<0.001) until milk production was terminated. Mean values for content of major milk constituents were 15.5% fat, 9.9% protein and 2.5% lactose. The content of fat and protein increased markedly with the lactation stage (P<0.001), while lactose showed a slight decrease (P<0.001). The milk composition was significantly affected by stage of lactation (P<0.001). There was a marginally significant decrease in protein:fat ratio (P=0.06) as protein was substituted by fat with stage of lactation. The caloric value of the milk averaged 8.7 kJ/g and increased significantly with the stage of lactation (P<0.001). The overall increase in milk gross energy content during lactation was 67.6%. The energy output averaged 7996 kJ/day at peak lactation and decreased significantly during the course of lactation (P=0.002).