to painful splitting and curling. Equine teeth have evolved to grind grasses and grains. They develop sharp points and caps that must be filed away or removed by a veterinarian (a procedure known as floating) in order for the horse to efficiently chew its food. All equines are prone to parasites and require periodic deworming to avoid infestations, which can lead to illness and even death in some cases. Pregnant, nursing, and senior equines may require specialized diets and more frequent veterinary care to maintain their health and comfort.
2.5.3 Feline (Domestic Cats)
Cats are often kept as indoor pets but can also be found living exclusively outdoors as community cats (which can consist of tame or unsocialized felines living singly, in small groups, or in larger colonies [Figure 2.2]). Cats are carnivores and have a higher protein requirement than other mammals. They require access to potable water and an area free from their feces and urine. Cats kept in crowded or confined conditions frequently develop upper respiratory and eye infections characterized by congestion, nasal and eye discharge, sneezing, and wheezing. They are also at a higher risk of developing skin conditions such as ringworm or scabies, and viral diseases including feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) [5]. Unaltered cats breed prolifically, and unneutered male cats are known to fight each other, which can cause wounds that may develop into painful abscesses. Outdoor cats need access to shelter from extreme hot and cold temperatures.
Figure 2.2 Community cats may be tame or unsocialized and often live in colonies.
Source: Kayte Wolf.
2.5.4 Canine (Domestic Dogs)
Dogs' relationships with people vary tremendously from being kept as indoor companions, as outdoor guardians protecting livestock or property, or kept strictly outdoors, sometimes chained or fenced in, with little human contact. Some states prohibit chaining dogs (often with certain exceptions), while chaining is allowed in others. Chains and collars must fit appropriately and not cause wounds or be so tight as to damage or become embedded in the skin (Figure 2.3). Dogs require an area clear of environmental hazards, access to potable water, and shelter that provides protection from extreme temperatures and allows them to stay dry and away from their feces and urine. Dogs are omnivores whose nutritional requirements are based on size, age, and activity level. They can develop viral diseases and parasite infections, some of which are zoonotic (contagious to humans), such as rabies and hookworms. Vaccination and deworming prevent these conditions from debilitating or killing dogs and protects humans from infection. Breeds with particular hair coats require grooming to prevent matting, which can become painful, interfere with mobility, and contribute to skin infection and disease. Dogs, especially seniors, require regular nail trimming to keep their nails from curling and becoming embedded in their paw pads. Routine dental care is required for most dogs, especially as they age. Painful dental disease later in life, requiring veterinary care, can become a serious health concern in the canine.
2.5.5 Small Mammals (Rabbits, Guinea Pigs, Mice, Rats, Ferrets)
Inappropriate husbandry and diet are common causes of disease in small mammals. Rabbits and guinea pigs are herbivores and require a high‐fiber diet, while rats and mice are omnivores. Ferrets, weasels, and mink are omnivores and require meat protein as well. Their nutritional requirements in captivity are best met by commercial diets developed for their species, supplemented with appropriate fresh foods. Guinea pigs require vitamin C in their diet as they are unable to produce this in their body like other mammals. Small mammals require constant access to potable water. Small mammals are intelligent and social animals. Providing appropriate housing will ensure they are able to display their normal behaviors. These species benefit from living in pairs or groups, but they can cause severe injuries and even death if fighting occurs. Adequately sized enclosures allow for the animals to eat, sleep, and exercise and allow them to be free from their waste. Some rodents require substrate or bedding for burrowing and sleeping. Enclosures should be free from hazards and cages with wire floors should be kept in good repair so as not to injure the animal's feet or entrap them. Cages with wire bottoms should always include a solid bed or resting platform where the animal can relieve itself from the constant pressure of standing on wire, which coupled with contact with feces and urine, leads to painful ulcerations and infection of the feet and hocks. Rabbit enclosures ideally have a thick and soft flooring, and wire or mesh flooring throughout the enclosure should be avoided. Rabbits do not have footpads, but have coarse fur covering the toes and paws. Rabbits kept in wire housing without access to soft, solid flooring commonly develop a condition called pododermatitis, which is an infection of the paw, and can be a serious and life‐threatening condition. Most small mammals do not do well in extreme heat or cold and some, like rabbits, are prone to heat stroke and must have access to a shaded area if housed outdoors. Overcrowding is stressful to small mammals and can cause them to fight with and cannibalize their cage mates and offspring. Dental health is very important in small mammals and is a common cause of medical concern in these species. All teeth in rabbits and guinea pigs are continuously growing, throughout the life of the animal, and they require oral examination at veterinary visits. Rabbits may suffer from malocclusion, a condition in which their teeth are misaligned causing them to become overgrown and curled, which can prohibit them from chewing their food. This condition is sometimes visible, but the teeth may grow backward into the cheek and so a visual inspection of the mouth is advised when malocclusion is suspected. Some species of rabbit (Figure 2.4) and guinea pig have long hair coats that require consistent grooming. Severe matting can lead to pain and skin infections.
Figure 2.3 Tight collars may become embedded in an animal's skin causing painful wounds and infection.
Source: Oregon Humane Society.
Figure 2.4 Angora rabbits require regular grooming to prevent matting of their long coats.
Source: Oregon Humane Society.
2.5.6 Avian
Birds kept as pets range from finches and pigeons to large parrots. They have adapted genetically over centuries so that their beaks are specially shaped to collect, open, and ingest the fruits and seeds native to their region of origin. Parrots have large, hooked bills for cracking open hard palm nuts, while finches have small triangular beaks designed to pluck tiny grass seeds from their stems. For this reason, birds in captivity must be provided with a diet modeled after what they were designed to eat in nature. There are hundreds of commercially available diets for every type of bird kept as a pet. Birds have high metabolisms and must eat frequently throughout the day, so food should always be available. When assessing feed, keep in mind that birds tend to drop spent seed hulls back into feed cups and hoppers, so what might appear as a full seed dispenser may actually be filled with empty seed hulls. Birds always require access to clean, potable water. Some birds, like pigeons and doves, may be suited to living in outdoor aviaries, but most pet birds are quite sensitive to cold temperatures. Cages should be large enough for the bird to move around, extend its wings, access its food and water, and be free from its waste. Birds require perches