Which of the following animals would NOT have a reticular groove?

The presence of a reticular groove is a characteristic feature of ruminants, which helps in directing liquid feed directly to the stomach without going through the rumen. When the animal suckles, the groove closes to ensure that milk bypasses the fermentation chamber (the rumen) and goes directly into the abomasum, allowing for proper digestion.

In the given options, calves (young cattle), kids (young goats), and piglets (young pigs) all have developmental forms that are associated with specific digestive adaptations, but the term "colt" specifically refers to a young male horse. Horses are non-ruminants and do not exhibit this specialized groove for directing milk to their digestive system. Instead, horse foals rely on a different digestive process suited to their species.

Thus, since colts are not ruminants and do not possess a reticular groove, they are correctly identified as the animal that would not have this anatomical feature. Understanding the unique digestive processes of different species is essential when considering their nutritional needs and how they process food.