ANSC Feeds Practice Exam

Which substance is not a source of non-protein nitrogen for feedlot cattle?

1. Urea

2. Ammonium sulfate

3. Ether extract

4. Tylosin

The correct answer is: Tylosin

Tylosin is an antimicrobial agent that is primarily used to promote growth and prevent disease in livestock, but it does not provide non-protein nitrogen. Non-protein nitrogen sources are compounds that can be converted into protein by the microorganisms in the rumen, helping to meet the nitrogen needs of ruminants like cattle. Urea and ammonium sulfate are commonly used non-protein nitrogen sources in ruminant diets. Urea is a simple nitrogen-containing compound that can be rapidly converted to ammonia in the rumen and then used by microbes to synthesize protein. Ammonium sulfate serves a similar function, providing nitrogen in a form that can be utilized by microbes as well. Ether extract refers to the fat content of feedstuffs and does not contribute to non-protein nitrogen. Since the question asks for a substance that is not a source of non-protein nitrogen, Tylosin stands out as it does not fulfill this role, making it the correct answer.