Effects of castration on growth and food intake cycles in young male reindeer (Rangifer tarandus tarandus)

To establish whether testicular factors are essential for the regulation of the growth cycle of reindeer, we investigated changes in food intake and body weight in intact and castrated males from March to December. The castrates gained less weight than the intact animals during summer, and during late summer food intake was lower in the castrates. During late September and early October, coinciding with testosterone peaks, the intact animals lost weight, whereas the weight of the castrates was stable. In spite of these differences, cyclic changes in food intake and rate of weight gain was seen also in the castrates. The regulation of the growth cycle in male reindeer can therefore only partly be dependent on testicular factors.