PSIV-1 - Effects of poor maternal nutrition during gestation on F0 and F1 ewe colostrum and milk composition and colostrum IgG

Abstract: High-quality colostrum and milk are critical for proper neonatal growth and immune system development. Immunoglobulin G (IgG) is the predominant antibody class in colostrum and is vital for passive immune transfer in sheep. There is limited understanding of how poor maternal nutrition during gestation (restricted- and over-feeding) might influence colostrum and milk composition and colostrum IgG concentrations and how F1 offspring colostrum and milk are impacted as a result of F0 maternal diet. The objective of this experiment was to determine if poor maternal nutrition during gestation impacts F0 and F1 colostrum and milk composition, including IgG concentrations. We hypothesized that maternal restricted-feeding would decrease, and maternal over-feeding would increase total solids, fat, and protein during early and transitional lactation and that restricted-feeding would increase IgG concentrations and over-feeding would decrease IgG concentrations in F0 and F1 ewe colostrum. Multiparous Dorset ewes pregnant (n = 46) with twins were fed 100% (control; n = 13), 60% (restricted; n = 17) or 140% (over; n = 16) of National Research Council (NRC) requirements. After birth and during lactation, dams were fed 100% NRC for lactating ewes so the nutritional insult only occurred during gestation. Resulting ewe offspring (n = 32) were raised on control diets and were bred between 16 and 19 mo of age. Colostrum samples were collected within 24 h of parturition and milk samples were collected at d 3 and d 21 postpartum. Colostrum and milk composition were evaluated using Brix Refractometry (total solids, g/dL) and spectrophotometry (crude fat, %; crude protein, %). Additionally, a radial immunodiffusion assay was used to determine IgG concentrations (mg/dL) in colostrum. A treatment by time interaction was observed for F0 colostrum crude fat where restricted-fed ewes had less fat than control-fed ewes (P ≤ 0.024). No interaction was detected for all other F0 and F1 composition variables (P ≥ 0.16). We did not detect a main effect of diet on F0 or F1 total solids, crude fat, and crude protein of colostrum nor milk (P ≥ 0.24). A main effect of time was observed for all variables where colostrum had greater total solids, crude fat, and crude protein compared with milk at d 3 and d 21 (P ≤ 0.0001). No effect of maternal diet on IgG concentrations were detected in F0 or F1 ewe colostrum (P ≥ 0.46). These data indicate that poor maternal diet has minimal effects on F0 and F1 ewe colostrum composition and IgG concentrations, and d 3 and d 21 milk composition. In addition, the impact of F0 diet on colostrum fat composition did not persist into the F1 generation.