| Microlivestock - Little-Known Small Animals with a Promising Economic Future |
|Part IV : Rodents|
Guinea pigs (Cavia porcellus) are promising microlivestock because they require little capital or labor; provide an inexpensive, readily available, palatable meat; have no odor, and are suitable for keeping indoors. In the highlands of the Andes, many Indians raise them to supplement diets based on grains and vegetables. Families eat them mostly on special occasions such as weddings and first communions, or they sell them to restaurants or peddle them in village markets.
The low cost of these small animals makes them available even to many landless peasants. For both the small farmer and apartment dweller, the guinea pig is a possible food reserve. It converts kitchen scraps and marginal wastelands into meat. According to estimates, 20 females and 2 males may produce enough meat year-round to provide an adequate meat diet for a family of 6.2
Since husbandry practices are simple and cheap, the guinea pig is an excellent source of supplementary income. An FAO study at Ibarra, Ecuador, showed that on small mountain farms the guinea pig provided more profit than either pigs or dairy cows, partly because its meat fetched high prices.
Although domesticated guinea pigs are mainly a food resource of Latin America, their use has also spread to parts of Africa and Asia. They are raised, for instance, in Nigeria, Cameroon, Ghana, Sierra Leone, Togo, and Zaire. In southern Nigeria, at least 10 percent of all households raise guinea pigs for food, with colonies of up to 30 animals per household. Guinea pigs are also raised in small cages or cardboard boxes by small farmers in the Philippines.3
The feeding efficiency is high: studies have shown that it takes between 3.2 and 5.7 kg of forage to produce 1 kg of growth. This makes guinea pigs more efficient than most farm mammals.
Guinea pigs seem especially adapted to the climate and forages of high-altitude zones, but the fact that they are being raised in Central and West Africa indicates that they are also adapted to the lowland tropics.
AREA OF POTENTIAL USE
APPEARANCE AND SIZE
Guinea pigs have stocky bodies, fairly short hind legs, and short, unfurred ears. Adults can weigh up to 2 kg, but an average-sized specimen is about 0.5 kg. They are 20-40 cm long (average 28 cm) and have no tail. In domesticated forms, the pelage may be smooth or coarse, short or long, and in some types the hairs form rosettes.4 Domesticated types come in colors ranging from white to dark brown, as well as piebald.5
The original home of the wild guinea pig is believed to have been the central highlands of Peru and Bolivia. Its domesticated descendants are important as meat animals mainly in that same area, but, as noted, they are also important in certain African and Asian countries.
A few strains are distributed worldwide as laboratory animals and pets.
Domesticated guinea pigs, as a whole, are in no danger of extinction, although some rare strains are threatened.
HABITAT AND ENVIRONMENT
These extremely adaptable animals are found in temperate zones and in the highland tropics, but they are usually kept indoors and protected from the extremes of weather. In Lambayeque and other departments of Peru, they are reared at elevations from sea level to more than 4,000 m. In areas where they are raised, daily temperatures fluctuate as much as 30ÝC. In the Bolivian or Peruvian puna region, for instance, day temperatures can be 22ÝC, while night temperatures are -7ÝC. However, they cannot survive freezing temperatures and they may not perform well when exposed to the full tropical heat and sunlight. Many people of the Peruvian highlands keep the animals in darkness (for example, in wood boxes with little or no light).6
The animal's original wild habitat is believed to have been an area of grasslands, forest edges, swamps, and rocks.
These herbivores can be raised on kitchen scraps, garden wastes, and weedy vegetation plucked from backyards or roadsides. Andean peasants mainly feed them potato peels, scraps of cabbage, lettuce, carrot, wild grasses, corn stalks, and the foliage of miscellaneous wild plants. Some barley and alfalfa is grown specifically for guinea pigs; it is cut green and sold in small bundles in the markets.
Guinea pigs mate throughout the year except when climate is excessively adverse. Domestic breeds average 2-3 young per litter, although larger litters sometimes occur. The gestation period is 65-70 days with an average of 67. Females come into estrus every 13-24 days, and there is a fertile postpartum estrus.
Females can become pregnant when merely 3 months old, and many produce 4 litters every year from then on. In principle, a farmer starting with 1 male and 10 females could see his herd grow to 3,000 animals in one year.
Newborns are so large that the female's pubic bones must separate for the birth. They emerge fully developed, with fur and open eyes. They look like miniature adults, and they start eating grass and other feedstuffs within hours. (For this reason, babies orphaned at birth have been known to survive.) Weaning may be reached as early as 21 days of age.
The life span in captivity is as long as 8 years, but animals used for breeding usually live only 3.5 years.
SUPER GUINEA PIGS
Even in their native region, guinea pigs have traditionally received little research attention. However, that began changing in the 1970s with the onset of meat shortages in Peru. (For a time the government restricted beef sales to only 15 days a month.)
For instance, in 1972 Peru began a guinea pig improvement project. Researchers from i a Molina National Agrarian University traveled throughout Peru gathering many kinds of guinea pigs short haired long haired black, white, yellow, brown, and even purple. Practically all the guinea pigs eaten in Peru are home grown, and researchers observed that the bigger ones were generally winding up in the stew, leaving the smaller ones for breeding. The people inadvertently were making the animals smaller. (This is a common phenomenon for many animals.)
To overcome it, the university research workers compared the mature size and growth rates of all the different guinea pigs. They selected and cross-bred the biggest, meatiest, and fastest-growing ones. This program, later taken over by Instituto Nacional de Investigacion y Promocion Agropecuaria (INIPA), produced remarkable results. The starting animals averaged little more than 0.5 kg, the resulting ones averaged almost 2 kg.
Peru's "super guinea pigs" are now getting international recognition. They have been introduced into the highlands of Honduras, where the animal is also part of the Indian cuisine. The FAO has shipped some to the Dominican Republic. In addition, Bolivia, Ecuador, and Colombia have all begun their own guinea pig improvement programs.
Within Peru the government has established 11 breeding stations to encourage the farming of guinea pigs for food. The goal is to provide better stud males to the people so that future animals will grow more quickly and reach a greater weight.
Guinea pigs generally congregate in small groups, normally made up of 5-10 adults. In favorable areas, however, such groups may coalesce into large colonies. The animals communicate incessantly among themselves, emitting a variety of squeaks and other noises.
Males, although good-natured with other species, often fight fiercely among themselves.
Guinea pigs are raised mainly for meat. Peru has about 20 million, which annually provide 16-17,000 tons of meat (only 4,000 tons less than Peru's sheep meat production).
Guinea pigs are used worldwide for studies on disease, nutrition, heredity, and toxicology, as well as for the development of serums and other biomedical research.
Guinea pigs require so little space that a small cage or pit can house up to 10 females and 1 male. They can be raised in cages with wire floors of small mesh as well. The labor required is low. A colony of 1,000 females reportedly can be properly cared for by one person. A layer of wood shavings, shredded paper, straw, and dried corncobs is usually recommended for bedding. The droppings are odorless, so the bedding does not need changing as often as with other animals. When the diet mainly consists of greens, much urine is produced, and then the beds have to be changed frequently.
When grown for meat, the young are weaned at 3-4 weeks and are ready for market in a matter of 10-13 weeks. Weight gain is rapid for the first 4-6 weeks, and then decreases. The carcasses normally dress out at about 65 percent, including the skin and legs. The meat's protein content is approximately 21 percent.7
In a few regions of Peru, guinea pigs are "herded" on the open range and retired at night into small adobe coops.
This small, inoffensive animal rarely bites, is easy to manage, and has no smell. It is an excellent supplemental meat supply. The improved breeds cannot climb or jump so that they are easy to contain. (Primitive "criollo" types, however, can jump.) If kept dry and given green vegetation, grain, and water, it survives in many environments.
A major constraint is consumer reluctance. Even in Latin America, attempts to promote guinea pig consumption outside the Indian communities have failed.
When raised in a clean environment and under normal feeding conditions, guinea pigs thrive and reproduce and do not need routine vaccinations or antibiotics that cattle, sheep, and pigs often require. However, guinea pigs can be carriers of Chagas' disease and salmonella. Further, they are susceptible to pneumonia if temperatures change abruptly when conditions are wet. Coccidiosis and internal and external parasites are also common.
Green forages and surplus fruits or by-products are critical to provide vitamin C, which the animal is unable to synthesize for itself.
RESEARCH AND CONSERVATION NEEDS
Since the greatest concentration of guinea pigs is found in the Andes, particular efforts should be directed towards this region. Already, research on guinea pigs has begun in some universities and government research stations in Colombia, Ecuador, Venezuela, Peru, and Bolivia, but more work is needed on matters such as:
- Breeding "elite" stock for distribution;
- Feeding and nutritional-requirement trials, especially for creating alternate feeds that peasants and commercial producers can use during seasons when conventional feeds are hard to get;
- Diseases and parasites that may limit production in small farming systems;
- Management practices concerning reproduction, housing, herd size, and feeding; and
- The genetic basis for weight gain and productivity.
Some research should be directed towards developing rations or introducing drought-resistant forages for the dry season because green forage is needed year-round. A range of practical and economical diets needs to be created.
Animal geneticists in Latin American countries should establish "elite" populations that can provide superior stock throughout the world. It can be anticipated that applying modern breeding methods to existing improved strains will result in great advances in a relatively short period and at little cost (see sidebar).
Three species of wild cavies (Cavia aperea, C. fulgida, and C. tschudii), close relatives of the guinea pig, are native to South America and are declining drastically. Research to preserve them is urgently needed. C. aperea is a widely used item of food in rural Brazil and other parts of South America.