Which type of livestock has no dietary essential amino acid requirement?

Ruminants with a functioning rumen are unique in their digestive system, which allows them to break down complex plant materials through fermentation and microbial activity. This fermentation process enables the rumen to synthesize essential amino acids from non-protein nitrogen sources. As a result, these animals do not have a specific dietary requirement for essential amino acids, as their microbial population can produce all the essential amino acids they need from the nitrogen and other compounds present in their diets.

In contrast, pigs and poultry, which are monogastric animals, require dietary sources of essential amino acids because they lack the specialized digestive capabilities that ruminants possess. Monogastric animals have a more straightforward digestive process and rely heavily on the amino acids provided by their feed. Therefore, they must consume these amino acids directly from their diets to meet their nutritional needs. Ruminants differ significantly from these animals due to their unique digestive system and microbial contributions, making them the correct choice in this context.