Project Number: 6440-21310-002-03
Project Type: Nonfunded Cooperative Agreement

Start Date: Apr 18, 2006
End Date: Mar 30, 2011

Objective:
Experiment 1: A grazing experiment will determine the effects that steroidal implants and rough hair coats retained in the summer months have on weight gain and physiology of steers on toxic tall fescue pasture in the late spring and early summer. Experiment 2: A grazing experiment will evaluate performance and physiology of yearling steers grazing a novel endophyte infected tall fescue developed for the upper transition zone (KYFA9301 tall fescue inserted with the AR584 novel endophyte).

Approach:
Experiment 1: A grazing experiment will be conducted with 60 steers that are assigned to six, 3.0-ha pastures of toxic tall fescue. Pastures will be assigned either with or without daily feeding of soybean hull pellets (2.3 kg/steer). Five steers will be implanted with a progesterone-estradiol ear implant and the other steers will not be implanted. Grazing and data collection will be conducted from late April until middle July for a two year duration. Average daily gain, rectal temperature, serum prolactin, and forage mass and ergovaline concentrations are response measures to be taken. Experiment 2: A grazing evaluation will be conducted with four TF entries: a TF genetic line (KAFA9301) with or without insertion of the AR584 NE, MaxQ (`Jessup¿ TF inserted with the AR584 endophyte), and `KY-31¿ infected with the TE. The four TF entries were no-till planted in the fall of 2006 in 1-ha pastures. Entries were assigned to pastures in a completely randomized design with 3 replications. The grazing experiment will be conducted for a 3-year duration, with grazing being initiated each year in early April and terminated following 84 days of grazing. Average daily weight gain, rectal temperature, sweating rate, serum prolactin, pasture carrying capacity, forage mass and nutritive values are the response measures to be taken.