The manager of an ancient deer park is urging Padstow residents to stay vigilant after poachers shot and butchered two of the animals before dumping the remains in a ditch.
Police believe the killings were conducted by a professional.
They have launched an investigation after a roe doe and her yearly offspring were found slaughtered at the Deer Park, Prideaux Place, on the night of Friday, January 10.
The rights to wild deer roaming on the estate are owned by Peter Prideaux-Brune, whose ancestors have lived there since 1592. Records indicate that the deer park could be the oldest in the country, dating back to the 5th century.
In 2005 a number of animals on the estate were wounded by crossbows.
Carmen Hocking, manager of Prideaux Place, said poaching could badly reduce deer numbers. "Poaching is armed theft and if unchecked has the potential to greatly diminish the wild deer population on the estate so the public are asked to be vigilant in helping us to crack down on this illegal activity," Mrs Hocking said.
"It is disappointing to have lost not only a healthy breeding female, most certainly pregnant, but also a young buck that would have been the future for our smallest native deer."
Mrs Hocking said poaching was driven by greed "fuelled by the high price of venison" and warned those buying from criminals of the dangers of passing on diseases to the consumer.
"Those unscrupulous enough to buy from the criminal are perhaps not aware of the dangers they could be passing on to the consumer by buying meat that has not been dealt with according to the food hygiene regulations or possibly been stolen in the most inhumane circumstances, often with dogs," she said.
"Nasty diseases can be passed into the food chain and can be easily missed by the untrained person dealing with the carcass, particularly if the illegal cull has taken place in poor light.
"The animal may have had an infected wound which in turn would infect the meat, and if not properly handled contamination can come from the soil where the animal was shot."
Padstow PC Andrew Spires is also warning consumers to take care.
"Those purchasing or slaughtering these animals should be aware of the pitfalls of consuming meat from carcasses killed in the wild, such as contamination by other animals, ground bacteria, butchers, personal contamination and poor storage," he said.
Anyone with information on this incident is asked to contact PC Spires via 101.