A bull was nailed to a cross and covered with silicone paint to create the mould which was named 'Holy Cow' by its creator, artist Tom Herck.
The display inside St John the Baptist of Kuttekovenin the Belgian town of Borgloon was branded a "satanic image and a disgusting insult to God" by the Katholiek Forum campaign group.
Members burned images of the display and staged a protest outside church where banners reading "stop blasphemy and degenerate art" were waved.
A statement issued by the local Catholic diocese and seen by Lifesitenews.com said: "The diocese of Hasselt is astonished at the 'Holy Cow' exhibition in the church of Kuttekoven.
"We are always ready to collaborate in dialogue with art projects in a church, and we can certainly appreciate humour.
"But a cow on the cross, on the spot where Christ hung on the cross, that is to our mind really a bridge too far."
Mr Herck said his creation sought to highlight the number of Belgian churches standing empty and the wastefulness of modern consumerism.
The model of the cow carcass is surmounted above a shallow pool containing 5,000 litres of milk.
The diocese was accused by Katholiek Forum of being "inconsistent" by criticising the exhibition but failing to intervene directly.