Date of Award:


Document Type:


Degree Name:

Doctor of Philosophy (PhD)


Animal, Dairy, and Veterinary Sciences

Committee Chair(s)

Kara J. Thornton-Kurth


Kara J. Thornton-Kurth


Allen J. Young


Marcus McGee


Sulaiman Matarneh


S. Clay Isom


As the population increases and available land for food production decreases, it is necessary for livestock producers to continually work towards increasing livestock production efficiency. In livestock operations, feed accounts for the majority of input costs associated with raising livestock. As such, it is necessary to improve growth and production of livestock animals, while also optimizing feed utilization. Different feedstuffs can be included in the diet of livestock animals to maximize growth and production. However, the effects of some of these novel feedstuffs on growth and production of livestock animals has not been elucidated. As such, we investigated the effects of including two novel alfalfa products, ProLEAF MAX™ (a pellet composed of alfalfa leaves) and ProFiber Plus™ (alfalfa stems), in the diets of beef steers, dairy heifers, and lactating dairy cows. We hypothesized that inclusion of ProLEAF MAX™ and ProFiber Plus™ in the diet would result in improved growth and performance of beef steers, growth and development of dairy heifers, and milk yield and milk components of lactating dairy cows. We found that inclusion of ProFiber Plus™ in the diet of beef steers and dairy heifers decreases feed costs without affecting overall growth in steers, but decreases growth in dairy heifers and inclusion of the two novel alfalfa products in the diet of lactating dairy cows results in improved milk yield and milk components. Additionally, we examined the effects of supplementing murine myoblasts with polyamines and polyamine precursors to further investigate novel products that may be able to be utilized in the diets of livestock animals to increase growth. We hypothesized that supplementation of polyamines and their precursors would result in improved growth of skeletal muscle cells (myoblasts). Treatment of myoblasts with polyamines and their precursors improves proliferation rates and alters mRNA expression of genes involved in polyamine biosynthesis, cell proliferation, and protein synthesis. Collectively, our observations suggest that various novel feedstuffs, whether it be alfalfa processed differently or amino acid derivatives (polyamines), have the potential to improve various growth and/or production measures. However, additional research is required to fully understand the potential of including these products in the diet.