Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Animal, Dairy, and Veterinary Sciences

Committee Chair(s)

Norris J. Stenquist


Norris J. Stenquist


John E. Butcher


Jeffrey L. Walters


C. Dennis Funk


A feeding trial was conducted comparing four finishing diets, typically fed in this area, two hormone implants zeranol (Ralgro) and estradiol 17-beta (compudose), and a feed additive. thirty-two Hereford steers were fed in individual pens to maintain accurate intake records. The four diets compared were: 1) a whole corn diet with a small amount of corn silage as roughage; 2) a high energy ground barley diet using corn silage and chopped alfalfa as roughage; 3) a total diet consisting of rolled barley, beet pulp, and ground alfalfa hay; and 4) a high energy rolled barley diet using corn silage and chopped alfalfa hay as roughage. All finishing diets were supplemented with a protein, vitamin, and mineral supplement containing monensin.

The cattle were fed in two phases--a growing and finishing phase. The diet comparisons were conducted only during the finishing phase. The implant and additive comparisons were made over both phases.

Diet had little effect on feed lot performance. Rate of gain and feed efficiency were not significantly affected. Voluntary intake of net energy for gain was significantly affected (p

The effect of diet was also significant for internal fat percent and marbling score (p

The difference between the implants used was very small. None of the feedlot performance traits were affected.

The feed additive Trigrr II produced significantly more (p

During the combined period, average daily gain and feed efficiency were both superior for Trigrr II fed cattle (p

Cattle implanted with zeranol fed Trigrr II consumed significantly greater amounts of net energy for gain and had heavier hot carcass weights than estradiol 17-beta implanted cattle or zeranol x control cattle.