Variation of plasma protein parameters in four free-ranging reindeer herds and in captive reindeer under defined feeding conditions

Plasma total protein (TP), albumin (ALB) and globulin (GLOB) concentrations and albumin/globulin ratio (A/G) were analysed from blood samples collected from free-ranging reindeer (Rangifer tarandus tarandus) herds at varying times of year. The same parameters were followed in nine captive reindeer with varying protein and energy intake. Variation in the blood constituents of free-ranging reindeer was analysed in relation to different extrinsic and intrinsic factors and compared to findings from captive animals, allowing the analysis of effects of protein and energy intake. There was large overall variation in TP, ALB, GLOB and A/G ratio in the free-ranging animals, ranging between 36-110 g/L, 18-59 g/L, 17-59 g/L and 0.5-2.1. The variation between months and years was significant for all variables except the A/G ratio, where no year effect was noted. Increase in live body mass was associated with a small significant increase and pregnancy with a small significant decrease in all dependent variables, except for the A/G ratio. Age did not have a significant effect on any of the blood constituents when body mass was included in the same model. In captive animals, feeding lichens with low protein content was related to a significant decline in TP, ALB and GLOB, but not in the A/G ratio, whereas feeding commercial ration increased plasma TP, ALB and GLOB significantly. Extrinsic factors such as season and year explained majority of variation in the blood constituents of free-ranging reindeer, whereas body mass, pregnancy and age had only a minor influence. It is concluded that plasma TP and ALB, and to a lesser extent GLOB and A/G ratio may serve as nutritional biomarkers of reindeer.