Which factor does NOT influence the protein requirements of livestock?

The protein requirements of livestock are influenced by various factors essential for their growth, maintenance, and overall health. Environmental conditions, however, do not significantly determine the protein needs of animals in the same direct way that factors like age, reproductive status, and growth rate do.

For example, an animal's age affects its protein requirements because younger animals, which are in a growth phase, typically need more protein to support the development of tissues and organs. Similarly, the reproductive status of an animal influences its protein needs; pregnant or lactating animals require additional protein to support fetal development and milk production. Growth rate is also a critical factor, as animals growing at a rapid pace have higher protein requirements to support that growth.

In contrast, while environmental conditions—such as temperature and housing—can impact an animal's overall health and performance, they do not directly alter the fundamental protein requirement set by biological processes. Instead, they may affect how efficiently an animal utilizes the protein it consumes, but they are not a primary determinant of the total protein needs required by livestock. Thus, it is clear that environmental conditions are not a direct influence on protein requirements in the same way other factors are.