Abstract
Background:
A vital part of the digestive system is the colon known as the middle section of the large intestine. The colon plays an important role in maintaining the overall health of the body by processing digested food, absorbing water, and balancing electrolytes.

Aim:
The current study aimed to identify and distinguish different aspects of the gross appearance of the colon in neonatal and adult local breed dogs and adaptations in the gastrointestinal tract associated with growth and development.

Methods:
The present study was performed on a total of 20 local breed dogs with no sex, which were obtained from the veterinary clinic in Aden Square and a local supplier. Ten of these dogs were neonatal at the ages of 1–15 days and were taken from their mothers and euthanized. These were considered the first group representing neonatal dogs, and the other 10 dogs were adults at ages ranging from 8 to 18 months and weights from 14 to 40 kg. The examined samples were directly measured to provide data that may assist future investigations related to histology and physiology.

Results:
Findings revealed significant differences in length and weight between neonates and adult local breed dogs, exhibiting more complex architectural features. These anatomical adaptations likely reflect the dietary shifts and increased functional demands of the adult gastrointestinal system.

Conclusion:
The present study proved that the colons of neonatal and adult local breed dogs have differences in macromorphometric measurements of all parts of the colon, which is considered a logical requirement for the type of food that each stage consumes.

Key words: Neonates, Adults, Dogs, Macromorphometric, Colon