The aim of the present study was to investigate the effect on growth of foals on two different diets, either a forage-based diet or a diet containing approx. 40 % concentrate. The report also includes a review of the pertinent literature on the effects of diet on mares’ milk and growth of horses. The hypothesis of the study was that a forage based diet will result in a similar growth pattern as a diet including more concentrates if the diets contain the same amount of energy, crude protein, lysine, calcium and phosphorous. The study was performed in a change-over design divided into two studies, Study 1 and Study 2. The forage based diet contained a silage with 42 % dry matter and 8,2 g digestible crude protein/MJ. The diet containing partly concentrate contained a silage with 78 % dry matter and 5,8 g digestible crude protein/MJ added with oat and soya bean meal. A general diet was calculated based on information from the staff at the stud farm on the horses normal energy intake.
Study 1 involved four Standarbred mares with stallion foals and they were studied during 2 times 27 days. For one period they were fed a forage-only and for the other period they were fed a diet containing 43 % concentrate (oat and soya bean meal) and forage. Both diets contained the same amount of CP, energy and lysine. The horses were kept outdoors with no feed during the day and in the stable during the night. Mare and foal were weighed day 1, 7, 14, 21 and 27 and tests of milk were taken day 27. The milk tests were analysed for total solids and ashes. No significant difference was observed between the two diets in mares weight and milk composition. The foals were significant heavier from day 7 when mares were feed the forage-only diet.
Study 2 involved eight weaned foals, four stallions and four mares of the Standard bred trotter breed and they were studied during 2*27 days. For one period they were fed a forage-only and for the other period they were fed a diet containing 38 % concentrate (oat and soya bean meal) and forage. Both diets contained the same amount of CP, energy and lysine. The horses were kept outdoors with no feed during the day and in the stable during the night. The horses were weighed day 1, 7, 14, 21 and 27 and on day 1 and 27 they were measured for withers height, height of the back vertical from the last rib, heart girth, the distance between carpus and the floor and the size of the fetlock joint girth. The horses were significant heavier from day 7 when fed the forage-only diet. No o...
