LAUSR

The objective of these studies was to determine the effects of increasing levels of CaCO3 with and without benzoic acid on weanling pig growth performance, fecal dry matter (DM), and blood Ca and P concentrations. In Exp. 1, 695 pigs (DNA Line 200 × 400, initially 5.9 ± 0.02 kg) were used in a 28-day study. Pigs were weaned at approximately 21 d of age and randomly assigned to pens and then pens were allotted to 1 of 5 dietary treatments. Treatment diets were fed from weaning (d 0) to d 14, with a common diet fed from d 14 to 28. Dietary treatments were formulated to provide 0, 0.45, 0.90, 1.35, and 1.80% added CaCO3 at the expense of ground corn. From d 0 to 14 (treatment period), ADG and G:F decreased (linear, P ≤ 0.01) as CaCO3 increased. From d 14 to 28 (common period) and for the overall experiment (d 0 to 28), there was no evidence for differences in growth performance between treatments. For fecal DM, there was a trend (quadratic, P = 0.091) where pigs fed the highest and lowest CaCO3 diets had the greatest fecal DM. Experiment 2 used 360 pigs (DNA Line 200 × 400, initially 6.2 ± 0.03 kg) in a 38-day study. Upon arrival to the nursery facility, pigs were randomly assigned to pens and then pens were allotted to 1 of 6 dietary treatments. Dietary treatments were fed in 3 phases with treatment diets fed from d 0 to 10 and d 10 to 24, and a common phase 3 diet fed from d 24 to 38. Dietary treatments were formulated to provide 0.45, 0.90, and 1.35% added CaCO3 with or without 0.5% benzoic acid (VevoVitall, DSM Nutritional Products, Parsippany, NJ) added at the expense of ground corn. There was no evidence (P > 0.05) for any CaCO3 by benzoic acid interactions. For the experimental period (d 0 to 24), there was a tendency for benzoic acid to increase ADG (P = 0.056), ADFI (P = 0.071) and G:F (linear, P = 0.014) as CaCO3 decreased. During the common period (d 24 to 38), pigs previously fed benzoic acid had increased (P = 0.045) ADG and marginally increased (P = 0.091) ADFI. For the overall study, pigs fed benzoic acid had increased ADG (P = 0.011) and ADFI (P = 0.030), marginally increased G:F (P = 0.096) and final BW (P = 0.059). Serum Ca decreased (linear, P < 0.001) as CaCO3 decreased in the diet. These data show that decreasing the CaCO3 content in the nursery diet immediately after weaning may improve ADG and G:F. Dietary addition of benzoic acid may also provide beneficial effects on ADG and ADFI, regardless of dietary Ca level.