Calcium chloride is a better calcium source rather than calcium carbonate for weanling pigs.

Two experiments were conducted to evaluate the effects of calcium (Ca) levels in weanling pigs (Landrace × Yorkshire × Duroc). In experiment 1, one hundred and eighty weanling pigs were randomly allotted to one of the three treatments. The treatments were low (Ca 0.60% in phase 1 and 0.50% in phase 2), standard (Ca 0.72% in phase 1 and 0.66% in phase 2), and high (Ca 0.84% in phase 1 and 0.72% in phase 2). In experiment 2, hundred and forty weanling pigs were randomly assigned to one of four treatments differing in Ca levels (high and low) and sources (CaCl and CaCO) in a 2 × 2 factorial arrangement. There were 10 pigs per replicate in both experiments, with 6 replicates in each treatment, and they were conducted in two phases (phase 1, days 0-14; phase 2, days 15-28). In experiment 1, body weight (BW), average daily gain (ADG), and growth to feed ratio (G/F) increased as the Ca level decreased ( < 0.05). P digestibility was higher in the low-Ca diet group than in the high-Ca diet group ( <0.05). In experiment 2, the final BW, ADG, and G/F increased in the CaCl diet group compared with the case in the CaCO diet group ( < 0.05). The digestibility of crude protein (CP), Ca, and P was higher in the CaCl diet group than in the CaCO diet group ( < 0.05). Cl levels were higher in the CaCl diet group than in the CaCO diet group ( < 0.05). The bicarbonate (HCO ), base excess (BE), and electrolyte balance (EB) levels were lower in the CaCl diet group than in the CaCO diet group ( < 0.05). Hematocrit increased as the Ca level decreased ( < 0.05). The HCO interacted with the Ca sources and thus, affected the Ca levels ( < 0.05). Bone ash, Ca, and P were downregulated in the low-Ca diet group compared with the case in the high-Ca diet group. Overall, the low dietary Ca supplementation led to greater growth performance. Furthermore, CaCl appeared to be a better Ca source than CaCO because of the greater digestibility of CP, Ca, and P, and improved EB.