The final letter of kakuda is dropped in a bahuvrīhi samāsa when it denotes age or condition of animals.,
The word अवस्था means the changes which things undergo by lapse of time, such as age &c. Thus असंजातं ककुदमस्य = असंजातककुत् = बालः \the young of an animal\, पूर्णककुत् = मध्यमवया \middle-aged animal\; उन्नतककुत् = वृद्धावया \old\. स्थूलककुत् = बलवान् 'strong', यष्टिककुत् = नातिस्थूलो नातिकृशः ॥
Why do we say when denoting a condition? Observe श्वेतककुदः ॥,