62 Growth Performance and Mineral Status of 6 Kg Piglets Fed Reduced Levels of Dietary Calcium

Abstract

Abstract Imbalances between calcium (Ca) and phosphorus (P) impair growth performance and bone mineralization. However, reducing dietary limestone may change the buffering capacity of feed in early nursery piglets, which may help prevent post-weaning diarrhea. An experiment was conducted to evaluate the impact of reducing Ca post weaning compared to recommendations outlined by NRC (2012) or a low P diet. Dietary treatments consisted of 1) Low Ca (LCa; Phase 1, 0.51% Ca and 0.47% STTD P), 2) NRC recommendations (NRC; Phase 1, 0.85% Ca and 0.42% STTD P), and 3) a recommendation lower in phosphorus (LP; Phase 1, 0.65% Ca and 0.36% STTD P). Each diet was fed over 4 phases. Piglets (n = 953; 276/275 Fast X PIC 800 genetics) were blocked by room, sex, and initial BW (6 kg). Feed intake and pig weights were recorded weekly. At 12 d and 41 d, blood was collected and Dual-X ray (DXA) measurements were taken using 8 piglets per treatment. Fecal scores were evaluated during wk 4 and 5. Data were analyzed using MIXED procedure of SAS (SAS Inst. Inc., Cary, NC). There were no differences observed in mortality, overall growth performance, plasma Ca and P, and scour scores at either time point. At 12 d, the bone mineral content was reduced (P = 0.001) in LP pigs compared to LCa and NRC. At 41 d, bone mineral content was reduced in NRC in comparison to LCa while LP was intermediate (P = 0.001). Plasma parameters showed an increased magnesium (Mg) and Ca:Mg in LCa (P < 0.01) that can be related to bone resorption to face Ca hypocalcemia. Pigs were healthy with no enteric challenges, limiting the ability to observe a benefit in fecal scores. In conclusion, piglets can maintain growth and bone mineralization through a short-term limestone removal program.