Mice and rats consume and contaminate food destined for livestock and other animals as well as humans. A mature rat can eat up to 30 g (1 oz) of feed (almost 10% of its body weight) in a day. A colony of 100 rats can consume over a ton of feed in 1 year. This exceeds the amount of grain required to feed a 454-kg (1,000-lb) horse for a year. This amount does not include feed that has been spoiled by rodent urine, droppings and hair, which can be as much as 10 times the amount consumed if they have free access to the feed storage area. In the U.S., the United States Department of Agriculture (USDA) estimates that the equivalent of more than $2 billion in feed is destroyed by rodents each year. (1)
Rodents can cause damage to building structures and may cause irreparable losses due to fires that result from the animals gnawing through wire insulation and exposing the live wires. Rodents are also responsible for aiding in the transmission of diseases such as salmonellosis, leptospirosis, trichinosis, and rabies. They can harbor and spread mites, ticks, lice, fleas, and internal parasites. Mice and rats can carry disease-causing organisms on their fur and their feet, contributing to the spread of disease and thwarting even the best-planned biosecurity measures.
Rodent control is essential, particularly due to the short pregnancy cycle of a rodent, which is a mere 19-21 days. One female mouse can produce five to 10 litters per year, each litter yielding five to six young that will be sexually mature in 6-10 weeks. In 1 year, a female rat is capable of producing 22 female offspring that may begin reproducing as soon as 3 months after birth.