The effects of feeding plant materials on feed efficiency and gas emissions in dairy cattle
Open Access
- Author:
- Heilman, Stephanie P.
- Area of Honors:
- Animal Sciences
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Gabriella Anne Varga, Thesis Supervisor
Gabriella Anne Varga, Thesis Supervisor
Troy Ott, Thesis Honors Advisor - Keywords:
- essential oils
secondary plant metabolites
oregano
rumen
dairy cattle - Abstract:
- Essential oils, due to their antimicrobial effects, have the potential to alter ruminal fermentation patterns through the inhibition of specific microorganisms. Alterations to ruminal fermentation could increase the efficiency of energy and nitrogen metabolism. In this study, over 60 essential oils native to the United States were analyzed in vitro using a batch culture incubation. From these results, one plant material, oregano, was then selected to be examined in the in vivo portion of the study. Oregano was supplemented at 500 g/cow/day to 8 multiparous Holstein cows, 4 of which were rumen cannulated, in a 4x4 Latin square design. The trial was a switch-over design with periods of 21 days each, for 14 days of adaptation and 7 days of sampling. Effects on milk yield, milk composition, ruminal fermentation, urinary nitrogen losses, urinary and fecal emissions, and total tract digestibility of nutrients were measured. In vitro incubations demonstrated that ruminal methane production was significantly reduced and NDF digestibility was improved for the plant material Origanum vulgare, therefore it was selected for in vivo experimentation. In the vivo experiment, Origanum vulgare significantly decreased ruminal methane production, illustrating the potential for improved energy efficiency. However, ammonia production within the rumen was significantly increased, suggesting that oregano supplementation may alter the metabolism of some bacteria in the rumen such that their capture of nitrogen is reduced.