Clinical trial design in feedlots.

As mentioned at the outset, the ultimate test of a product or procedure must be under field conditions and is best obtained from controlled studies of field use. Economic justification for use is based on this information. Each producer places a different value on attributable benefits such as improved health or growth performance. These values also change with fluctuating market values of cattle and feed. This makes determining the cost-benefit ratio of any procedure or product a moving target. Addressing this issue requires the clinically relevant and statistically significant differences that practitioners should be able to generate if they follow the guidelines presented here. There already exists a number of unusable studies. We suggest that those interested in undertaking this challenge be uncompromising in their experimental design. To be reliable, studies must follow the recommendations outlined above. Without sound field trial design and execution which ensures that the information is reliable and statistical significance which ensures that the differences are real, clinical outcomes cannot be extrapolated to economic justification. Any other course leads to making less than optimal recommendations on product use because of a lack of clinically relevant information.