suckling vs lactation

suckling and lactation both are nouns.

Word	Noun	Adjective	Verb	Adverb
suckling	Yes	No	No	No
lactation	Yes	No	No	No

As nouns, suckling and lactation are synonyms defined as:

suckling (noun)	lactation (noun)
feeding an infant by giving suck at the breast	feeding an infant by giving suck at the breast
a young mammal that has not been weaned	the production and secretion of milk by the mammary glands
an infant considered in relation to its nurse	the period following birth during which milk is secreted