Feed preferences of ponies.

Preference trials were conducted with mature ponies. In Trial 1, oats were compared with oats plus sucrose. Four of six pony geldings selected oats plus sucrose, but one pony demonstrated a dislike for sucrose and one selected from the bucket on the right side regardless of content. Oats, maize, barley, rye and wheat were compared in Trial 2 using six mature pony mares. Oats were the preferred grain, with maize and barley ranking second and third respectively. Wheat and rye were the least preferred. Even though the ponies demonstrated preference, the total intake at a given meal was not greatly depressed when only the less palatable grains were fed. In Trial 3, pony mares selected a diet containing 20 per cent dried distillers' grain and 80 per cent of a basal mixed diet of maize, oats, wheat bran, soybean meal, limestone and molasses over 100 per cent basal mixed diet, but selected the basal diet over diets containing 20 per cent blood meal, beet pulp or meat and bone meal and 80 per cent basal diet. They did not differentiate against diets containing 20 per cent alfalfa meal or 10 or 5 per cent meat and bone meal when the diets were compared to the basal mixed diet.

Effect of interval between doses on response of the pony to sodium bicarbonate.

Three pony geldings were given sodium bicarbonate orally in order to study the effect on blood pH and bicarbonate and to determine if frequency of dosing influences the response. In a preliminary study, it appeared that a carry-over effect might occur if the interval between dosing was only 2 days. The ponies received 2 doses of sodium bicarbonate (400 mg/kg) 7 days apart in trial one and then in trial two they received 2 doses of sodium bicarbonate 4 days apart. The sodium bicarbonate was mixed with 2 liters of warm water and given through a nasogastric tube on each trial day. Blood samples were taken before dosing, and every half hour after for five and a half hours. The blood was analyzed for pH and bicarbonate. There did not seem to be a carry-over effect due to sodium bicarbonate administration since there was little difference in the responses between the first and second doses of each trial.

Salt consumption and the effect of salt on mineral metabolism in horses.

The voluntary salt consumption of mature unexercised horses was measured weekly for up to 45 weeks. Voluntary intake among horses was quite variable ranging from 19 to 143 g of salt per day and was inversely related to total salt intake (salt in feeds plus voluntary intake). Mean daily voluntary salt consumption was 53 g. Season of the year did not influence voluntary intake. In preference tests which evaluated every two choice combination of 0.2% and 4% NaCl in test diets fed daily for four days, ponies generally preferred diets containing the lower amount of salt. In similar preference studies which used NaHCO3 as a sodium source, ponies always preferred the diet containing the lower level of NaHCO3. Metabolism studies employing diets containing 1, 3 or 5% NaCl showed that urinary excretion was the major excretory pathway for sodium and chloride. Fecal excretion, intestinal absorption and retention of sodium were not affected by level of salt intake. Urinary calcium excretion was unaffected by salt intake but calcium and phosphorus absorption and retention were enhanced when ponies were fed diets containing 3 or 5% sodium chloride. Magnesium and copper metabolism were unaffected by salt intake. Horses voluntarily consume relatively large amounts of sodium chloride but it is likely that not all voluntary consumption is related to the salt requirement of the horse. Habit and taste preference could also be involved. Salt consumption at the levels used in these studies does not appear to be detrimental to the metabolism of other minerals in the horse.