Growth in the reindeer.

The growth of the reindeer from birth to adulthood is cumulative consisting of a rapid weight accretion during summers followed by a weight loss or stasis during winters. The birth weight of the newborn calves is about 5.3 kg. The peri- and neonatal growth rate is rather high, with a greatest individual daily weight gain as high as 400 g. The polynomial growth curve and its first order time derivative of calves show a deceleration of weight gain towards the autumn. The weight of calves at an age of 10 months was 36 to 40 kg. Adult body weight is reached by females at an age of 3 to 4 years and by males on average a year later. Serum alkaline phosphatase activity showed a negative linear correlation with age and weight in calves and it was highest both in calves and adults in summer. The creatine Phosphokinase activity in both calves and adults was higher in summer than in other seasons. Serum inorganic phosphorus was highest in the growing calves. On the other hand serum thyroxine (T4), blood glucose and calcium did not show significant age-dependent or seasonal variations.