Breeding and Genetics Exam 1 Practice

Macro-environment factors are broad external conditions that influence all animals in a population and are largely outside the control you can apply to each animal individually. Climate fits because it represents the general weather and ambient conditions of the area where the herd is kept, affecting the group as a whole—things like temperature, humidity, rainfall, and seasons shape feed intake, metabolism, reproduction, and disease pressure. You can manage the micro-environment inside a barn (like ventilation or bedding) to mitigate climate effects, but these are separate, controllable factors within the living space, not the broad climate itself. The other options are not macro-environment: age is an intrinsic trait of each animal, disease status varies among individuals, and castration is a specific management procedure performed on animals.