The association between immunoglobulin G in sow colostrum and piglet plasma.

Colostrum provides newborn piglets with energy and passive immunity and is essential for survival of the piglets. The plasma concentration of immunoglobulin G (IgG) in piglets is dependent on several factors, most importantly the concentration of IgG in sow colostrum (colostrum IgG). The main aims of this study were to investigate the variation in concentration of colostrum IgG between herds and the individual sows within herd and to investigate factors associated with plasma IgG concentrations in piglets (piglet IgG). From 4 herds (A to D), 876 piglets from 62 sows were included in the study. Colostrum was sampled from sows immediately after expulsion of the first piglet and before the first suckling (t1), midway through farrowing (just after the sixth piglet was born; t2), and after the last piglet was born (t3). At d 1, 0.5 mL blood from piglets was collected in tubes containing EDTA, and IgG concentrations were analyzed. Mean colostrum IgG concentration across all herds was 53.9 g/L. Herd A had mean colostrum IgG of 38.3 g/L, whereas the other 3 herds (B,C, and D) had mean colostrum IgG of 47.4, 60.4, and 67.8 g/L, respectively. Colostrum IgG at t1, t2, and t3 across all herds was 56.2, 53.7, and 42.5 g/L, respectively. Mean concentration of piglet IgG across all samplings was 21.7 g/L. Multilevel linear regression analysis was performed with piglet IgG (g/L) as outcome. In this model, the herd effect accounted for 9% of the total variance and 34% of the variance resided at sow level. Piglet IgG was associated with herd, birth order (), body mass index (BMI) > 17 (kg/m), and colostrum IgG at t1 (g/L) with an overall -value < 0.01. Herd D had the highest predicted mean level of piglet IgG. The main model predicted that piglet IgG decreased linearly by 0.4 g/L with each piglet born ( < 0.01). The model also predicted an increase by 0.1 g/L for each gram per liter extra colostrum IgG in colostrum ( = 0.03). Piglets with a BMI above 17 kg/m had a greater piglet IgG (+4.5 g/L) than those with a BMI at 17 kg/m or below ( < 0.01). Concentrations of colostrum IgG varied largely between herds and between sows. The largest variation of piglet IgG was mainly on the piglet level, supporting the complex nature of IgG production and uptake. However, the strong association between colostrum IgG and piglet IgG shows that increased IgG level in colostrum will improve the levels of IgG in piglets and potentially increase survival of the piglets.