Effects of restricted- and over-feeding during gestation on colostrum and milk composition and offspring circulating immunoglobulin G concentrations in multiple generations of sheep

High-quality colostrum and milk are critical for neonatal growth and immune system development. Immunoglobulin G (IgG), the predominant antibody in colostrum, is vital for passive immune transfer in sheep. It is unknown if poor maternal nutrition during gestation influences colostrum and milk composition, and IgG concentrations over multiple generations. We hypothesized that poor maternal nutrition (restricted- or over-feeding) during gestation would alter F0 and F1 colostrum and milk composition and IgG concentrations in their colostrum and alter serum IgG in F1 and F2 offspring. Multiparous Dorset ewes (n = 46) pregnant with twins were fed 100 % (control; n = 13), 60 % (restricted; n = 17) or 140 % (over; n = 16) of National Research Council (NRC) requirements until parturition. Following lambing, all dams were fed 100 % NRC requirements during lactation. Offspring of these ewes (n = 85; F1) were managed similarly on 100 % of NRC requirements and are referred to as CON-F1, RES-F1, or OVER-F1, corresponding with dam diet. F1 ewe offspring (n = 36) were bred between 16 and 19 mo of age. Offspring of these ewes (n = 60; F2) were managed similarly on 100 % of NRC requirements and are referred to as CON-F2, RES-F2, or OVER-F2, corresponding with granddam diet. Colostrum samples from F0 and F1 ewes were collected within 24 h of parturition and milk samples were collected at d 3 and 21 postpartum and analyzed for total solids, crude fat, crude protein (colostrum and milk), and IgG concentrations (colostrum only). Serum samples were collected from F1 and F2 offspring at 7 d of age and analyzed for IgG concentrations. A treatment by time interaction (P ≤ 0.024) was observed for F0 crude fat where colostrum from restricted-fed ewes had less fat than colostrum from control-fed ewes. However, total fat in d 3 and 21 milk samples were similar across treatments. Colostrum had greater total solids, crude fat, and crude protein compared with milk at d 3 and d 21 (P ≤ 0.01). Maternal diet had no impact on IgG concentrations in F0 or F1 ewe colostrum (P ≥ 0.46). A treatment by sex interaction (P = 0.007) was observed for F1 offspring serum IgG concentrations where RES-F1 and OVER-F1 ewes and CON-F1 and OVER-F1 rams had between 44.9 – 50.7 % less IgG than CON-F1 ewes. No impact of maternal diet was observed on F2 offspring serum concentration of IgG (P = 0.40). In this experiment, maternal diet had minimal effects on F0 and F1 colostrum and milk composition or IgG concentrations. However, maternal diet may limit IgG absorption in F1 offspring in a sex- and diet-specific manner but does not persist into the F2 generation.