| Abstrakt: |
An experiment using 360 lambs was conducted to compare the effects of calcium carbonate (ground limestone) and calcium chloride on feedlot performance and phosphatic urolithiasis when fed in a 15% alfalfa hay diet containing added phosphorus or sodium bicarbonate. The incomplete factorial involved 0 and 2% sodium bicarbonate, 0.22 and 0.47% phosphorus and 0.31, 0.56 and 1.06% calcium in the diet. At the 0.56% calcium level, both ground limestone and calcium chloride were used, while only ground lime-stone was utilized at the higher calcium level. Sodium bicarbonate was fed only with the low phosphorus series of treatments.The higher level of phosphorus (0.47%) reduced weight gains, but additional calcium, in the form of ground limestone or calcium chloride, overcame this depression. Calcium chloride appeared to be less effective than ground limestone in overcoming the weight gain depressing effect of high dietary phosphorus, but was more effective in preventing urinary calculi. The greatest incidence (50 to 52%) of calculi was obtained by feeding 0.47% phosphorus and 0.31% calcium or the lower level of ground limestone (0.56% calcium). However, by increasing dietary calcium to 1.06% with ground limestone, calculi incidence was reduced (29% vs. 50%). With the feeding of calcium chloride (0.56% calcium level), calculi were completely prevented in the high phosphorus treatment. The feeding of sodium bicarbonate in these 15% alfalfa hay diets did not promote calculi formation, although it did cause a slight increase in urine alkalinity. |
