ANSC Feeds Practice Exam

Which cow breed has higher NEm requirements when both weigh 1000 lbs?

1. Brahman cows

2. Nonpregnant Angus cows

3. Both breeds have equal requirements

4. NEm requirements are dependent on environment

The correct answer is: Nonpregnant Angus cows

The nonpregnant Angus cows exhibit higher net energy maintenance (NEm) requirements compared to Brahman cows when both weigh 1000 lbs. This difference is primarily attributed to the physiological and genetic factors inherent in each breed. Angus cows, which are a breed developed for beef production in temperate climates, have a leaner body composition and typically possess a higher metabolizable energy requirement due to their efficient growth and production traits. Their cellular processes and maintenance metabolism tend to demand more energy for basic bodily functions when they are not in a state of pregnancy. Brahman cows, on the other hand, have evolved in hotter, more humid environments and have adaptations that allow them to thrive with relatively lower energy inputs. They are generally hardier and can maintain themselves on less energy than Angus cows due to their ability to tolerate heat stress and utilize forages in a more efficient manner under certain environmental conditions. These breed differences can lead to variations in energy requirements even among individuals of the same weight, making the Angus breed comparatively more demanding in terms of energy needs in this specific scenario.