Dog food
Dog food is specifically formulated food intended for consumption by dogs and other related canines. Dogs are considered to be omnivores with a carnivorous bias. They have the sharp, pointed teeth and shorter gastrointestinal tracts of carnivores, better suited for the consumption of meat than of vegetable substances, yet also have ten genes that are responsible for starch and glucose digestion, as well as the ability to produce amylase, an enzyme that functions to break down carbohydrates into simple sugars – something that obligate carnivores like cats lack. Dogs evolved the ability living alongside humans in agricultural societies, as they managed on scrap leftovers and excrement from humans.
Dogs have managed to adapt over thousands of years to survive on the meat and non-meat scraps and leftovers of human existence and thrive on a variety of foods, with studies suggesting dogs' ability to digest carbohydrates easily may be a key difference between dogs and wolves.
The dog food recommendation should be based on nutrient suitability instead of dog's preferences. Pet owners should consider their dog's breed, size, age, and health condition and choose food that is appropriate for their dog's nutritional needs.
In the United States alone, the dog food market was expected to reach $23.3 billion by 2022.
History
Prior to being domesticated, dogs, being canines, fended for themselves and survived on a carnivorous diet. After adapting them for protection, work, and companionship, people began to care at least in part for their nutritional needs. The historic record of this changing approach dates back at least 2,000 years.In 37 BCE, Virgil talks about the feeding of dogs in his Bucolics:
Around 70 CE, Columella wrote his book On Agriculture in which he addresses the feeding of dogs:
In the Avesta, written from 224 to 651 CE, Ahura Mazda advises:
By Medieval times, dogs were more seen as pets rather than just companions and workers which affected their quality of the diet to include "Besides being fed bran bread, the dogs would also get some of the meat from the hunt. If a dog was sick, he would get better food, such as goat's milk, bean broth, chopped meat, or buttered eggs."
In France, the word pâtée began to appear in the 18th century and referred to a paste originally given to poultry. In 1756, a dictionary indicates it was made of a mixture of bread crumbs and little pieces of meat given to pets.
In 1781, an encyclopedia mentioned an earlier practice of removing the liver, heart, and blood of a downed stag and mixing it with milk, cheese, and bread, and then giving it to dogs.
In 1844, the French writer, Nicolas Boyard, warned against even giving tallow graves to dogs, though the English favored them, and suggested a meat-flavored soup:
In England, care to give dogs particular food dates at least from the late eighteenth century, when The Sportsman's dictionary described the best diet for a dog's health in its article "Dog":
In 1833, The Complete Farrier gave similar but far more extensive advice on feeding dogs:
It was not until the mid-1800s that the world saw its first food made specifically for dogs. An American electrician, James Spratt, concocted the first dog treat. Living in London at the time, he witnessed dogs around a shipyard eating scraps of discarded biscuits. Shortly thereafter he introduced his dog food, made up of wheat meals, vegetables and meat. By 1890 production had begun in the United States and became known as "Spratt's Patent Limited".
In later years, dog biscuit was sometimes treated as synonymous with dog food:
Canned horse meat was introduced in the United States under the Ken-L Ration brand after World War I as a means to dispose of excess horses no longer needed for the war. The 1930s saw the introduction of canned cat food and dry meat-meal dog food by the Gaines Food Co. By the time World War II ended, pet food sales had reached $200 million. In the 1950s Spratt's became part of General Mills. For companies such as Nabisco, Quaker Oats, and General Foods, pet food represented an opportunity to market by-products as a profitable source of income.
Physiology
Like the other members of the order Carnivora, the dog has a short digestive tract and longer canine teeth, poor ability to synthesise arginine, vitamin D, and α-linolenic acid. Although the dog is a carnivore it has some omnivorous metabolic function such as converting β-carotene to vitamin A, tryptophan to niacin, cysteine to taurine, and linoleic acid to arachidonic acid.Dogs can synthesise glucose from glucogenic amino acids in the liver and kidney if the dog is unable to obtain adequate starch, glucose, or glycogen.
Impact and sustainability
As of 2018, there are around 470 million pet dogs. Pet food production is responsible for 20-30% of the environmental impacts from animal production. It has been estimated that global greenhouse gas emissions from dog and cat dry food represents around 1.1%−2.9% of global emissions, an amount close to the total emissions of countries such as Mozambique or the Philippines.Like humans, dogs are omnivores. There is research on alternative protein sources for pet food including insects and algae.
A life-cycle analysis of contemporary pet foods suggests wet foods for cats and dogs tend to have a larger impact than dry foods. It also suggests there are substantial opportunities for improvement in "all phases of the pet food life cycle, including formulation, ingredient selection, manufacturing processes" and so on.
Commercial varieties
Most commercially produced dog food is made with animal feed grade ingredients and comes dry in bags or wet in cans. Dry food contains 6–10% moisture by volume, as compared to 60–90% in canned food. Semi-moist products typically run 25–35%. Isotopic analysis of dog food in the Brazilian market have found that they are basically made of maize and poultry by-products.Dry
Dry dog food usually consists of bagged pellets that contain 3-11% water. It makes up the vast majority of pet foods.Manufacturing process
Dry food processing is popular in the pet food industry, as it is an efficient way to supply continuous production of feed in many varieties. It is energy efficient, allows for large amounts of feed to be used, and is cost effective.To make dog kibble, a process known as extrusion is done. A simple extruder consists of a barrel, helical screws, and a die. Feed ingredients are solid at room temperature; therefore, the extrusion process of these ingredients requires a temperature above 150 degrees Celsius, achieved by the use of steam, hot water, or other heat sources in order to soften or melt the mixture and allow for fluidity through the barrel. During the extrusion process, the high amounts of pressure applied to the mixture forces it to enter through the die before exiting the extruder completely, where it is cut to its desired size by a rotating fly knife.
Unfortunately, the extrusion process actually denatures some of nutritional elements of the food. Taurine deficiency has been found in dogs and cats fed extruded commercial diets. Not usually considered an essential nutrient for dogs, taurine is plentiful in most whole meats, whether raw or cooked, but is reduced in extruded diets. Taurine deficiency could also be due to the use of rendered, highly processed meat sources that are low in taurine. Regardless of the cause, taurine is now artificially supplemented back into the diet after processing in the production of most commercial pet food.
Wet
Wet or canned dog food usually is packaged in a solid or soft-sided container. Wet food contains roughly 60-78% water, which is significantly higher in moisture than dry or semi-moist food. Canned food is commercially sterile ; other wet foods may not be sterile. Sterilizing is done through the process of retorting, which involves steam sterilization at 121 degrees Celsius. A given wet food will often be higher in protein or fat compared to a similar dry food on a dry matter basis ; given the canned food's high moisture content. A larger amount of canned food must be fed in order to meet the dog's required needs. Grain gluten and other protein gels may be used in wet dog food to create artificial meaty chunks, which look like real meat. This food is usually used for old dogs or puppies.Manufacturing process
After ingredients are combined, they are placed in a tank at the end of a canning machine. From there, the mixture is forced through an opening and onto a metal sheet, forming a thickness of 8 to 12mm. Next, the mixture is heated to thoroughly cook the ingredients. Heating can be done through the means of ovens, microwaves or steam heating. The sheet containing a layer of feed is passed through the heat source that displays heat to the top and bottom of the tray, allowing the internal temperature to reach 77 degrees Celsius at a minimum. Once cooked, this mixture can be directly placed into cans to form a loaf or it can be cut into "meaty" pieces for chunks and gravy formulas.Semi-moist
Semi-moist dog food is packaged in vacuum-sealed pouches or packets. It contains about 20-45% water by weight, making it more expensive per energy calorie than dry food.Most semi-moist food does not require refrigeration. They are lightly cooked and then quickly sealed in a vacuum package. This type of dog food is extremely vulnerable to spoiling if not kept at a cool temperature and has a shelf life of 2–4 months, unopened.
Dehydrated and freeze-dried
or freeze-dried meals come in raw and cooked forms. Products are usually air-dried or frozen, then dehydrated to reduce moisture to the level where bacterial growths are inhibited. The appearance is very similar to dry dog pellets. The typical feeding methods include adding warm water before serving. There is some concern of nutrients, such as vitamins, being lost during the dehydration process.Specialty small batches sold through specialty or online stores generally consist of some form of cooked meat, ground bone, pureed vegetables, taurine supplements, and other multivitamin supplements. Some pet owners use human vitamin supplements, and others use vitamin supplements specifically engineered for dogs.