ABSTRACT
This chapter shows that feeding selenium (Se)-biofortified hay increases whole-blood Se concentrations, enriches the nasal microbial diversity, improves calf performance, and aids in disease prevention in the feedlot. The study design consisted of 2 treatment groups, with three pens of five animals per treatment. The weaned beef calves at baseline ranged in age from 6 to 9 months and originated from the Oregon State University beef ranch, Corvallis, OR, USA. Using a randomized complete block design, calves were blocked at the time of weaning by body weight, and fed a mixture of alfalfa and grass hay twice daily. The amount of hay fed was adjusted weekly to ensure that calves had all the hay they wanted for consumption yet with minimal wastage. Principal component analysis plots showed that baseline samples formed a separate cluster when compared to samples collected after the 9-week feeding trial, and samples collected 3 weeks after entering the feedlot.
