Date of Graduation

5-2023

Document Type

Thesis

Degree Name

Master of Science in Animal Science (MS)

Degree Level

Graduate

Department

Animal Science

Advisor/Mentor

Brittni Littlejohn

Committee Member

Jeremy G Powell

Second Committee Member

Charles R Looney

Keywords

Complete Blood Count;Endotoxin;Lipopolysaccharide;Prenatal Programming;Toxic Fescue

Abstract

The objective was to evaluate the influence of pregnant cattle grazing endophyte-infected tall, toxic, fescue (E+) during gestation on innate immune response of male offspring to an endotoxin challenge. Crossbred multiparous cows (n = 36) were bred to Red Angus sires and housed in replicated E+ or novel endophyte-infected, non-toxic, fescue (NE+) pastures prior to breeding and throughout gestation. From this calf-crop, a subset of post-weaned steers (n = 8 E+; n = 8 NE+) were selected for a lipopolysaccharide (LPS) challenge. Blood was collected every 30 min beginning 2 h prior to (Pre-LPS) and continuing 9 h following (Post-LPS) the administration of LPS (0.5 ug/kg of body weight). Cortisol and glucose were analyzed every 30 min, while complete blood count (CBC) and rectal temperature (RT) were analyzed every h during the pre- and post-LPS periods. Pre- and post-LPS hematocrit were increased in calves born to dams that grazed E+ relative to NE+ during gestation (P = 0.02; P < 0.01). Post-LPS lymphocyte counts were decreased in calves born to dams consuming E+ relative to NE+ during gestation (P = 0.01). Post-LPS eosinophil counts were increased in calves born to dams consuming E+ relative to NE+ during gestation (P = 0.05). No other variables were influenced by treatment (P > 0.05). Preliminary results of altered hematology profiles in response to an endotoxin challenge suggest an altered innate immune response of male offspring born to dams consuming E+ relative to NE+ fescue during gestation and highlight the need of ongoing research to determine corresponding cytokine profiles.

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