Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 2/23/2007
Publication Date: 7/8/2007
Citation: Brown, K.R., Harrison, L.R., Klotz, J.L., Strickland, J.R., Boling, J.A., Matthews, J.C. 2007. Neotyphodium Coenophialum Alters Blood Metavolites Involved in Nitrogen, Energy, and Minteral Metabolism in Growing Steers. J. Anim. Sci. Vol. 85, Suppl. 1/J. Dairy Scit. Vol. 90, SUppl. 1/Poult. Sci. Vol. 86 Suppl 1. pg 418.
Technical Abstract: Blood metabolite changes in steers during summer-long grazing of toxic endophyte-infected pastures were investigated as a part of a larger study for determination of physiological genomic and metabolic pathways for alkaloid metabolism. Blood cell counts, differentials, and serum metabolites of growing steers grazing fescue infected either with high (HE) or low (LE) amounts of toxic endophyte for 85 d were determined. Experimental treatments consisted of steers grazing either a LE (6.8% infection) mixed grass-tall fescue pasture (n = 9; BW = 266 ± 10.9 kg; 5.7 ha) or a HE (62.8 % infection) tall fescue pasture (n = 10; BW = 267 ± 14.5 kg; 5.7 ha). Blood samples were collected by jugular venipuncture on d 0, 36, 57, and 85 of the study. Values presented are those for which no treatment × day of trial interaction was observed. Steers grazing HE pastures had decreased serum alanine transferase (P < 0.02, 10.2%), aspartate aminotransferase (P < 0.04, 9.9%), albumin (P < 0.01, 4.3%), and albumin:globulin (P < 0.05, 6.4%). No changes were observed for '-glutamyl transferase, blood urea nitrogen, creatitine, total protein, globulin, or total bilirubin compared to the LE steers. Lactate dehydrogenase (P < 0.01, 13.4%) and glucose (P < 0.05, 6.3%) were lower in the HE steers. Serum concentrations of magnesium, sodium, and chloride did not differ, but phosphorus was lower (P < 0.02, 5.9%) in steers grazing the HE pasture compared to LE. No differences were observed in packed cell volume, red blood cells, hemoglobin, white blood cells, segments, lymphocytes, monocytes, and eosinophils between the two treatments. This study suggests chronic exposure to toxic endophyte-infected tall fescue selectively decreased blood components that are important indices for growth and metabolic function.