Large melanoma mass in the forelimb of a dairy animal

Objectives

A Friesian dairy cow developed an aggressive mass in the distal part of the left forelimb, which finally led to the death of the animal. The animal was permanently housed in an intensive dairy farm located in the province of Zaragoza, Spain.

The animal was born on 20 March 2018. The cow’s development was normal during its breeding and rearing period. The animal gave birth for the first time in May 2020, at 26 months of age. The second calving was April 2021. The cow’s average milk production was 39 liters per day. The animal had not suffered any disorder or condition throughout its life so far.

However, in July 2021, the dairy cow began to develop a rapidly growing, strange-looking mass on the left forelimb, close to the hoof. Since then, the animal presented a slight lameness that grew in intensity as the mass also developed. . Initially, an elastic band was placed at the insertion of the mass to cut off blood flow and necrotise the lesion. However, it was not effective. At the slightest contact of the mass with any object, bleeding occurred. The animal progressively worsened and even suffered an abortion. [...]