Many parasites affect farm animals and livestock, and they can be of both internal and external varieties. Among internal species, Meat and Livestock Australia lists various worms, protozoa and flukes as invasive parasites. External species, called ectoparasites, include flies, ticks and lice.
According to Hobby Farms, the target and life cycle of every parasite may be different. Liver fluke, for example, always begins its life cycle in a ruminant, such as cow, before being excreted and infecting snails to finish its life cycle. Alternatively, the barber pole worm infects goats and sheep first, before seeking a human host. Size of parasites can also vary greatly. Protozoa are microscopic, whereas tape worms can achieve a length of up to 20 feet. Many ectoparasite species may be introduced into farm animals' environments in greater numbers as a result of certain weather conditions. Flooding or heavy rains, for example, can cause an upsurge in populations of biting insects, particularly various flies, midges and mosquitoes. Ticks can also become more prevalent. The effects of parasites on farm animals and livestock can range from annoying to extremely dangerous. Depending on species and host, parasite infestation can lead to such debilitating and deadly situations such as severe blood loss, critical decrease in appetite and diarrhoea. Parasites can also act as vectors for disease, leaving farm animals more susceptible. External species like ticks, flies and lice, can interrupt grazing behaviors and create open sores on animals. Ultimately, untreated infestation can stunt growth and reproduction among animals, harm lactation and damage the quality of fleeces as well.