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United States Department of Agriculture

Agricultural Research Service

Title: Temporal Changes in Rectal Temperature and Serum Prolactin O Weaned Braham-Influenced Heifers Grazing Eendophyte-Infected Tall Fescue Pasture

Authors
item Aiken, Glen
item Looper, Michael

Submitted to: Journal of Animal Science Supplement
Publication Type: Other
Publication Acceptance Date: February 23, 2005
Publication Date: July 24, 2005
Citation: Aiken, G.E., Looper, M.L. 2005. Temporal Changes in Rectal Temperature and Serum Prolactin O Weaned Braham-Influenced Heifers Grazing Eendophyte-Infected Tall Fescue Pasture. Journal of Animal Science Supplement. 83(1):261.

Interpretive Summary: Temporal Changes in Rectal Temperature and Serum Prolactin of Weaned Brahman-Influenced Heifers Previously Grazing Endophyte-Infected Tall Fescue Pasture. G.E. Aiken*1 and M.L. Looper2, USDA-ARS, 1Forage-Animal Production Research Unit, Lexington, KY, 2Dale Bumpers Small Farms Research Center, Booneville, AR. Suckling calves maintained on endophyte-infected tall fescue can potentially suffer from fescue toxicosis. Twenty heifers (1/4 to 3/8 Bos indicus) were utilized to monitor rectal temperature and serum prolactin concentrations for 8 d post-weaning (Feb. to Oct.) from endophyte-infected tall fescue pastures. Heifers were removed from cows at approximately 0800 h on 19 October at a mean age of 226 ± 37 d and mean 205-d weaning weight of 220 ± 42 kg. During the post-graze weaning period, heifers grazed common bermudagrass [Cynodon dactylon (L.) Pers.] and were supplemented 2.3 kg/d per heifer of a commercial weaning ration with an antibiotic ingredient. Rectal temperatures were recorded, and serum was collected to quantity concentrations of prolactin at approximately 1000 h on the day of weaning (d 0) and on d 1, 2, 3, 6, and 8 post-weaning. Daily ambient temperature during the monitoring period averaged 19.7 ± 2.3OC. Rectal temperatures were never critically high (> 40.9OC), but were influenced (P < 0.001) by day. Rectal temperatures were higher on days 0, 1, 4, and 6 (mean = 40.4 ± 0.4OC). Rectal temperatures declined below 39.5OC on day 2, when ambient temperature decreased, and on d 8 to 39.4 ± 0.5OC. Concentrations of prolactin averaged 3.2 ± 3.7 'g/ml on d 0 and increased (P < 0.001) to 22.0 ± 13.5 'g/ml by d 6. Increases in prolactin over the 8 d post-weaning period indicated there could be a concurrent rapid reduction in circulating ergot alkaloids. Keywords: Beef Heifer, Fescue Toxicosis, Weaning, Prolactin

Technical Abstract: Temporal Changes in Rectal Temperature and Serum Prolactin of Weaned Brahman-Influenced Heifers Previously Grazing Endophyte-Infected Tall Fescue Pasture. G.E. Aiken*1 and M.L. Looper2, USDA-ARS, 1Forage-Animal Production Research Unit, Lexington, KY, 2Dale Bumpers Small Farms Research Center, Booneville, AR. Suckling calves maintained on endophyte-infected tall fescue can potentially suffer from fescue toxicosis. Twenty heifers (1/4 to 3/8 Bos indicus) were utilized to monitor rectal temperature and serum prolactin concentrations for 8 d post-weaning (Feb. to Oct.) from endophyte-infected tall fescue pastures. Heifers were removed from cows at approximately 0800 h on 19 October at a mean age of 226 ± 37 d and mean 205-d weaning weight of 220 ± 42 kg. During the post-graze weaning period, heifers grazed common bermudagrass [Cynodon dactylon (L.) Pers.] and were supplemented 2.3 kg/d per heifer of a commercial weaning ration with an antibiotic ingredient. Rectal temperatures were recorded, and serum was collected to quantity concentrations of prolactin at approximately 1000 h on the day of weaning (d 0) and on d 1, 2, 3, 6, and 8 post-weaning. Daily ambient temperature during the monitoring period averaged 19.7 ± 2.3OC. Rectal temperatures were never critically high (> 40.9OC), but were influenced (P < 0.001) by day. Rectal temperatures were higher on days 0, 1, 4, and 6 (mean = 40.4 ± 0.4OC). Rectal temperatures declined below 39.5OC on day 2, when ambient temperature decreased, and on d 8 to 39.4 ± 0.5OC. Concentrations of prolactin averaged 3.2 ± 3.7 'g/ml on d 0 and increased (P < 0.001) to 22.0 ± 13.5 'g/ml by d 6. Increases in prolactin over the 8 d post-weaning period indicated there could be a concurrent rapid reduction in circulating ergot alkaloids. Keywords: Beef Heifer, Fescue Toxicosis, Weaning, Prolactin

Last Modified: 11/27/2014
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