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United States Department of Agriculture

Agricultural Research Service

Title: Growth performance and immune function of fall-born beef calves weaned from endophyte-infected tall fescue pastures on different dates in the spring.)

Author
item Caldwell, James
item Coffey, Kenneth
item Coblentz, Wayne
item Ogden, Robin
item Jennings, John
item Hubbell iii, Donald
item Kreider, David
item Rosenkrans, jr., Charles

Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Type: Experiment station
Publication Acceptance Date: 8/15/2007
Publication Date: 12/15/2007
Citation: Caldwell, J.D., Coffey, K.P., Coblentz, W.K., Ogden, R.K., Jennings, J.A., Hubbell III, D.S., Kreider, D.L., Rosenkrans, Jr., C.F. 2007. Growth performance and immune function of fall-born beef calves weaned from endophyte-infected tall fescue pastures on different dates in the spring. Arkansas Agricultural Experiment Station Research Series 553. Arkansas Animal Science Department Report 2007. 10:70-72.

Interpretive Summary:

Technical Abstract: Fall-born calves grazing Neotyphodium coenophialum-infected tall fescue [Lolium arundinaceum (Schreb.; E+) Darbysh.] should benefit from early weaning because of reduced exposure to fungal toxins, but our earlier work did not support this theory. A total of 238 Gelbvieh x Angus calves were used in a 3-yr study to determine the optimal time to wean fall-born calves grazing E+ tall fescue. Cow-calf pairs were assigned to one of four weaning dates: 1) March 16 (177 ± 4.7 d of age;MarW), 2) April 13 (204 ± 4.7 d of age; AprW), 3) May 11 (236 ± 4.7 d of age;MayW), and 4) June 8 (264 ± 4.8 d of age; JuneW). Body weight on the June weaning date, actual weaning weight, ending BW (14 d following the June weaning date), daily gain between birth and the ending date, and BW change between the March and June weaning dates increased linearly (P < 0.05) with delayed weaning date. Antibody titers to bovine virus diarrhea (BVD) and infectious bovine rhinotracheitis (IBR) at the time of weaning decreased in a linear manner (P < 0.05), and bovine respiratory syncytial virus (BRSV) antibody titers tended (P = 0.09) to increase cubically across weaning dates. Response to BVD and IBR vaccination measured 14-d post-weaning increased (P < 0.05) linearly and that of BRSV increased (P < 0.05) linearly and quadratically across weaning dates. Antibody titers changes for BVD and BRSV between weaning and the end of the study increased linearly (P < 0.05) and that for IBR (P < 0.05) increased linearly and quadratically. Therefore, delaying the weaning of fall-born calves grazing infected fescue pastures until early June may be beneficial for calf growth and immune function.

Last Modified: 8/24/2016
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