THE EFFECT OF DIETARY-PROTEIN ON REPRODUCTION IN THE MARE .2. GROWTH OF FOALS, BODY-MASS OF MARES AND SERUM-PROTEIN CONCENTRATION OF MARES DURING THE ANOVULATORY, TRANSITIONAL AND PREGNANT PERIODS

The effect of 4 different diets, in terms of protein quantity and qual ity, on total serum protein (TSP), albumin and globulin was investigat ed. Non-pregnant mares that were not lactating (n = 36), pregnant mare s that had foaled (n = 24) and their foals (n = 24) were used in this study. Daily total protein intake had no effect on blood protein conce ntrations in the mares. Total protein intake and quality (available es sential amino-acids) did affect the body mass of mares during lactatio n. When mares were fed the minimum recommended (National Research Coun cil 1989) total daily protein, foal mass decreased by approximately 25 % at weaning compared to the foals whose dams were on a higher level o f protein intake. The TSP concentrations of foals at birth were on ave rage 10 g/l lower than those of the mares. Albumin concentrations of f oals during the first 60 days of life were on average 2-3 g/l lower th an those of the mares. Globulin concentrations of foals were approxima tely 5 g/l lower than those of mares at weaning.