Short answer. No. Article 1574 says there is no warranty against hidden defects for animals sold at fairs or public auctions, or for livestock sold as condemned. Buying your cow at a public auction generally removes this particular warranty as a remedy for the defect you discovered.
What the law says
There is no warranty against hidden defects of animals sold at fairs or at public auctions, or of live stock sold as condemned.
Civil Code, Article 1574 — No Warranty at Fairs/Auctions or for Condemned Livestock. Read the full provision →
Public auction sales fall squarely within this exception
Article 1574 carves out a specific exception to the usual warranty against hidden defects: "there is no warranty against hidden defects of animals sold at fairs or at public auctions, or of live stock sold as condemned." Because you purchased your cow at a public livestock auction, your transaction falls directly within the first category the article describes, meaning the ordinary hidden-defects warranty that would otherwise apply to a sale of animals does not extend to this purchase.
Why the law treats auction and fair sales differently
Sales at fairs and public auctions typically involve buyers who have the opportunity to inspect the animals themselves, often in a competitive bidding environment where the seller may have limited individual knowledge about each specific animal's condition. The public, open nature of these sales is different from a private sale where a seller deals directly and personally with a single buyer, and the law adjusts the warranty rules to reflect that different context.
The rule also reaches livestock sold as condemned
The article extends the same exception to "live stock sold as condemned." Livestock explicitly sold under that designation is understood by both parties to carry known risk, and a buyer purchasing on those terms cannot later invoke the hidden-defects warranty for problems that the condemned designation was already signaling. This situation is conceptually similar to the auction exception in that the buyer is on notice, one way or another, that the ordinary warranty protections do not fully apply.
What this means for your specific purchase
Because your cow was bought at a public auction, Article 1574 indicates you cannot rely on the warranty against hidden defects to seek a remedy for the defect you later discovered. This does not necessarily mean you are without any recourse whatsoever in every possible scenario — for instance, if the seller made specific fraudulent representations about the animal's condition, different legal principles concerning fraud could potentially come into play — but the hidden-defects warranty specifically is not available to you given how and where the sale took place. Inspecting animals carefully before bidding at any future auction is the practical lesson this article leaves buyers with.