PSIII-15 - The interactions of change in nutrition after artificial insemination on plasma metabolites, steroid hormones, and uterine histotroph in beef heifers

The objective was to evaluate the impact of nutritional changes after artificial insemination (AI) on plasma metabolites, steroid hormones, and uterine histotroph. Beef heifers (n = 50) were randomly assigned to a post-AI dietary treatment (High=161.5% or Low=77.45% of maintenance energy) until uteri were flushed for embryo recovery (d14). Blood samples were collected on d -3, 0 (AI), 3, 6, 9, 12, and 14 for analysis of plasma non-esterified fatty acid (NEFA), total protein (protein), glucose, cholesterol, and progesterone concentrations. Uterine flushes (UF) were analyzed for concentrations of Mg, P, S, K, Ca, Cu, Zn, Se, Mn, Co, B, Cr, and Fe. Plasma NEFA, protein, glucose, cholesterol, and progesterone concentrations were analyzed as repeated measures in SAS (PROC MIXED). Mineral concentrations in UF were analyzed using the MIXED procedures in SAS. Diet influenced plasma NEFA concentrations, with Low heifers having elevated concentrations (P < 0.01); however, diet did not influence plasma protein, glucose, cholesterol, or progesterone concentrations (P > 0.10). Plasma NEFA, glucose, and progesterone concentrations changed over time (P < 0.05), but protein and cholesterol did not differ over time (P > 0.10). Diet by time interactions influenced plasma NEFA, protein, and cholesterol concentrations (P < 0.05), but glucose and progesterone concentrations were not different (P > 0.10). Presence of a recovered embryo by time interaction influenced plasma protein concentrations (P < 0.04), but NEFA, glucose, cholesterol, and progesterone concentrations were not affected by the interaction (P > 0.10). Embryo recovery and diet by embryo recovery by time did not impact plasma NEFA, protein, glucose, cholesterol and progesterone concentrations (P > 0.10). When an embryo was recovered, Mg (P = 0.02) and S (P = 0.02) were decreased in UF. Diet and diet by embryo recovery did not affect UF mineral concentrations (P>0.10). In conclusion, post-AI nutrition influenced plasma NEFA, protein, glucose, cholesterol, and progesterone concentrations. Additionally, uterine histotroph mineral concentrations were affected by presence of an embryo.