Evaluating peripartum calcium administration strategies to improve sow farrowing performance and piglet livability

A total of 933 sows were used to evaluate peripartum calcium administration protocols on sow farrowing performance and piglet livability. Sows were blocked by parity and average stillbirths in previous parities then allotted to 1 of 3 treatments with 310 to 312 replications. Treatments included: (i) Control with sows receiving no intervention; (ii) 25 g of a calcium chloride-based product (CaCl₂) top-dressed daily each morning from approximately d 112 of gestation until farrowing; or (iii) calcium gluconate injection (CaG) administered to primiparous and multiparous sows (15 or 20 mL injection, respectively), at the time that a sow was classified as "at-risk" defined by the sow, in the current parturition, having more than 16 pigs, longer than 1 h since the birth of the last pig, 2 or more stillbirths, or farrowing duration exceeding 4 h. On a subset of sows farrowing duration, sow blood metabolites, sow urine pH, and pig immunocrit were analyzed. Parity category (P1, P2 to P4, or P5+), treatment, and their interaction were fixed effects while average past stillbirth category (<0.5, ≥0.5 and ≤1, or >1 stillborn/litter) was a random effect. There were no differences in total born, percentage born alive, or percentage stillborn between treatments; however, when at-risk sows were compared, administration of CaG decreased stillbirths and increased percentage of pigs born alive (P ≤ 0.006). There was an interaction between Ca protocol and parity category for birth to cross-foster mortality (P = 0.035) where mortality was lowest in P1 Control sows (P < 0.05) compared to all other treatment × parity category combinations except for P1 CaG sows which were intermediate. When considering all sows, sows fed CaCl₂ had increased blood Cl and ionized Ca (P < 0.001) compared to Control or CaG sows. Sows provided CaG had increased blood glucose (P = 0.026) compared to Control and CaCl₂ sows. Sows given CaCl₂ or CaG had decreased urine pH (P = 0.001) compared to Control sows. Pig immunocrit ratios tended (P = 0.068) to differ due to Ca protocol, with CaG offspring having a numerical increase compared to other treatments. In conclusion, in the overall population, top-dressing CaCl₂ before farrowing or injecting CaG peripartum altered sow metabolites but did not influence farrowing performance. However, when comparing at-risk sows, administration of CaG decreased stillbirths and increased percentage of pigs born alive.