PSXII-10 Providing excess metabolizable protein prior to calving shifts the protein composition of colostrum and early post-colostrum serum proteomic profiles in neonatal beef calves.

The effect of oversupplying metabolizable protein (MP) pre-partum on pre-partum colostrum protein composition and calf serum protein composition was determined to characterize the nutritionally modulated transfer of biomarkers from mother to calf. Thirteen primiparous crossbred Hereford cows were assigned to a high protein (HP; 133% of MP requirement, n = 6) or control (CON; 100% of predicted MP requirement, n = 7) treatment. Cows were individually fed their treatment diet from d -55 relative to parturition. Colostrum was sampled equally from all quarters and calf serum was collected prior to and 6-hours post colostrum consumption. Colostrum contained 213 distinct detectible proteins. Of these, 11 proteins showed a greater than 2 fold increase in abundance from HP cows. Three of these proteins (AMER3, G3N1Y3, G3MZ21) show 1.4–6.9 fold depletion in the serum of calves fed colostrums from HP dams. The other eight proteins did not appear in detectible levels in the calves’ serum before or after colostrum. An additional 16 proteins were reduced more than 2 fold in the colostrum from HP cows, relative to CON. A total of 179 distinct proteins were detectible in the serum sampled before and after colostrum consumption. Of these, 28 were more than 2 fold greater prevalence in the serum of HP calves. Eighteen of these proteins were detectible in colostrum, with 10 enriched up to 1.25 fold in HP colostrum, and 8 depleted down to 0.82 fold in treatment colostrum. Additionally, 19 proteins were greater than 2 fold less prevalent in the serum of calves feed colostrum from HP dams, including haptoglobin antioxidant protein and IαI-heavy-chain inflammatory regulators. Thus excess of MP promotes a shift in select proteins, including immune-regulators, in colostrum which promotes an associated shift in different factors and biomarkers in calf serum post-colostrum consumption.