Doctor of Philosophy / Department of Animal Sciences and Industry / Bradley J. Johnson / Research regarding rumen epithelial adaptation and potential mechanisms during the
transition period of the dairy cow is lacking. The rumen epithelium has a tremendous capacity
for the absorption of volatile fatty acids (VFA) produced from microbial fermentation in the
rumen. Absorption of VFA from the rumen pool delivers energy substrates to the animal and
provides stability to the rumen environment. Increased epithelial surface area from the
development and adaptation of rumen papillae facilitates VFA absorption. Manipulation of the
diet to alter rumen fermentation can have positive effects upon the rumen papillae development
supporting VFA absorption. We hypothesized that enhancing rumen epithelial surface area
through dietary alterations could lead to greater VFA absorption and improve rumen stability.
Experiments were conducted to determine the effects of diets formulated with cane molasses to
stimulate the production of ruminal butyrate and thereby increase rumen epithelial surface area
and to investigate a potential mechanism for glucagon-like peptide-2 (GLP-2) to impact
epithelial development. Feeding cane molasses in the dry period improved dry matter intake
during the close-up period and during lactation. Milk production was increased for cows that
were fed cane molasses during the dry period. Ruminal absorption of valerate was greater during
the close-up period than the far-off period but was not influenced by the addition of cane
molasses. Total VFA concentration measured during the dry period was not affected by the
addition of cane molasses to the diet. The presence of glucagon-like peptide receptor (GLP-2R)
mRNA was confirmed in bovine tissue obtained from rumen epithelium, omasum, abomasum,
duodenum, jejunum, ileum, large intestine, and pancreas. The greatest level of expression of
mRNA for GLP-2R was in the small intestine and large intestine. Expression of GLP-2R mRNA
during the prepartum period tended to be increased with the addition of cane molasses.
Postpartum expression of GLP-2R was not increased by supplementing cane molasses in the dry
cow diet. Results from these experiments indicate that dry cow diets formulated to contain cane
molasses can positively influence transition cow performance and that the presence of glucagonlike
peptide-2 receptor could play a pivotal role in rumen epithelial development.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/8544 |
| Date | January 1900 |
| Creators | Miller, William Frederick |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
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