Veterinary Nutrition exam questions: topics, study tips and free sample questions

Answer: A. The milk urea nitrogen is a measure of nitrogen metabolism (protein) in the dairy cow. The normal value is about 14 mg/dl. Samples from at least 8 cows are measured and the values are averaged to reflect a mean. Significant increases mean that an excessive amount of rumen utilizable protein is being fed. Substantial excess of protein (more than 19%) in the ration may prolong days open and services per conception after parturition. High milk urea nitrogen levels could also rise if the amount of fermentable carbohydrate becomes sub-optimal, because energy is required to deaminate the normal amount of amino acids in the liver and excrete the products in the kidney. Thus if the diet has insufficient carbohydrate, or excess fiber,the milk urea nitrogen could also increase. Do not confuse excess protein in a ration with Non-protein nitrogen poisoning, an acute convulsive, rapidly fatal toxicity typically due to excess urea or other NON-protein nitrogen sources.

Answer: E. Ionophore antibiotics, (like monensin, lasalocid) cause rumen microorganisms to produce more propionic acid (a volatile fatty acid (VFA)) and less acetic and butyric acids. Propionic acid releases more energy per unit weight than the other 2 VFAs, and is important in beef cattle production Think of Ionophore toxicity associated with feed mixing errors (like when too much monensin is mixed into a ration), or when a horse gets into the medicated poultry or cattle feed accidentally. Horses are especially sensitive.

Answer: D. Histamine from mast cell tumors (MCT) acts on H2 receptors on gastric parietal cells to increase acid (HCI) production and release. This increased acid release decreases gastric DH and predisposes to gastric and duodenal ulceration. Dogs with MCT may present with a chief complaint of vomiting, diarrhea, weight loss, and melena due to GIT ulceration. On serum chemistries/CBC look for a regenerative anemia, decreased total protein, and increased BUN consistent with GI blood loss. Tx: Use histamine blockers in dogs with clinical signs, those with a high MCT burden, pre- surgically, or if complete excision cannot be achieved. Examples include: - Diphenhydramine (H1 blocker): only effective to block peripheral effects of histamine - Ranitidine and famotidine (H2 blockers) - Omeprazole (proton pump inhibitor): will prevent acid production, but does not block H2 receptor