'Heifer,' or 'cow' in a negative sense denotes falsities.

'The heifer whereby labor has not been done,' as mentioned in Deuteronomy 21:3, signifies the innocence of the external self in ignorance.

'The red heifer,' as mentioned in Numbers 19, signifies unclean truth of the natural principle which is cleaned by burnings.

In Numbers 19:2, this signifies the good of the natural man. (Apocalypse Explained 364[6])

(References: Arcana Coelestia 4503 [1-11], Genesis 9, 15, 15:9)