PS9-27. Repeatability of Colostrum Quality Measures in Sows Across Two Parities.

Abstract Colostrum yield and quality measures, such as immunoglobulin G (IgG) concentration, vary widely among sows. However, it is unclear whether these traits remain consistent in subsequent parities. The objective of this study was to investigate the repeatability of pre-farrowing serum IgG, colostrum yield, Brix values, and colostrum IgG. Data was collected from 32 nulliparous (P0) gilts starting at 100 days of gestation (dg) and pigs were followed into their first (P1) and second (P2) farrowings. At approximately 110 dg, serum samples were collected during the P0 and P1 gestation periods. Colostrum was collected after the birth of the first piglet and Brix values were obtained using a digital refractometer. Colostrum intake of each piglet was calculated based on piglet weight change until 24 h post-farrowing. The sum of colostrum intakes for the litter was used to determine approximate colostrum yield for each sow. Serum and colostrum IgG concentrations were quantified using a commercially available ELISA (Bethyl Laboratories, Montgomery, TX). Repeatability between measures was analyzed using a two-way mixed effects intraclass correlation coefficient model (ICC), where a value closer to one suggests greater repeatability. Pearsons’s correlation coefficient was used to determine correlations between measures. Within individual, pre-farrowing serum IgG had high repeatability (ICC = 0.84; 95% CI: 0.68-0.92; P < 0.001) and was positively correlated (r = 0.85; P < 0.001) between parities. Similarly, Brix values were repeatable (ICC = 0.77; 95% CI: 0.57–0.88; P < 0.001) and positively correlated (r = 0.78; P < 0.001) between parities. Colostrum IgG exhibited repeatability within individuals (ICC = 0.68; 95% CI: 0.44–0.83; P < 0.001) as well as a strong correlation between parity (r = 0.76; P < 0.001). Both Brix values and pre-farrowing serum IgG were positively correlated with colostrum IgG concentration for all animals (r = 0.59; P < 0.001; r = 0.61; P < 0.001, respectively). Colostrum yield had a lower repeatability (ICC = 0.41; 95% CI: 0.08–0.66; P < 0.05) but demonstrated a positive correlation across parity (r = 0.50; P < 0.01). These results suggest that colostrum yield and quality traits are consistent within individuals between parities and could potentially aid in management and retention decisions.