Microlivestock - Little-Known Small Animals with a Promising Economic Future (b17mie) հղում աղբյուրինb17mie.htm |
Part II : Poultry |
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Although geese (Anser spp.) were one of the first domesticated animals, they have yet to receive the level of commercial or industrial exploitation of chickens or even ducks. Thus, their global potential is far greater than is generally recognized today.
Domestic geese are easily managed and well suited to small-farm production; they are among the fastest growing avian species commonly raised for meat, and they have immediate application in many developing countries.
These birds are especially appropriate for providing farmers a supplemental income. With little extra work they supply nutritious meat, huge eggs, and rich fat for cooking, as well as soft down and feathers for bedding and clothing. Moreover, their strident voices sound the alarm when strangers or predators approach. They are especially well suited to aquatic areas and marshy lands and are completely at home in warm shallow waterways. Nevertheless, they can thrive away from water. In fact, wherever pasture is available geese readily adapt to captivity.
Geese are grazers, and can be raised almost exclusively on pasture. They are excellent foragers, and on succulent grass can find most or all of their own food. With their powerful bills they pull up grasses and underwater plants and probe soil and water for roots, bulbs, and aquatic animals. Their long necks make them adept at gleaning weeds from hard-to-reach places - such as fence rows, ditches, and swampy areas that baffle larger livestock. They will also feast on vegetable trimmings, garden and table leftovers, canning refuse, and stale baked goods. Like other poultry, they pick up shattered grains of rice, wheat, barley, and other crops, which can reduce the bothersome problem of weeds volunteering in subsequent years.
Geese are available worldwide. In most climates, they require little or no housing. Given reasonable care and protection from predators, mortality can be extremely low.
AREA OF POTENTIAL USE
Worldwide.
APPEARANCE AND SIZE
Domestic geese come in an assortment of colors, sizes, and shapes. There are two main types, however. Descendants of the wild greylag goose (Anser anser) make up the domestic breeds common in North America and Europe, including the Embden, Toulouse, Pilgrim, American Buff, Pomeranian, Sebastopol, and Tufted Roman breeds. These are generally best suited to temperate climates. On the other hand, descendants of the wild "swan goose" (Anser cygnoides) make up the geese of Asia, including the Chinese and "African" types. These breeds seem better suited to hot climates.
In addition to these, many European and Asian countries have their own local breeds and types, and there are even several wild species that show some potential for captive production.
With their long legs and webbed toes, geese are equally at home walking or swimming. Avid walkers, they march long distances to find forage, but return home at dusk. Accomplished and graceful swimmers, geese are able to take to water soon after they hatch. Despite their large size, some domestic breeds - especially the leaner ones - have retained the ability to fly.
DISTRIBUTION
Geese are found worldwide, but goose farming is nationally important only in Asia and Central Europe.
STATUS
Domestic geese are not threatened, although much local variation among the breeds is being lost.
HABITAT AND ENVIRONMENT
Most geese adapt well to hot climates - as long as some shade is available. Their waterproof feathers help them adapt well to high rainfall regions. They also tolerate extreme cold. (For instance, in Canada, geese are wintered outdoors in subfreezing temperatures, with merely 'e simple shelter from wind.)
For tropical developing countries, the Chinese type, which is widely kept in Southeast Asia, is especially promising. Smaller than most geese (although ganders can weigh over 5 kg), they are the best layers, the most active foragers (making them economical and useful as weeders), the most alert and "talkative," and they produce the leanest meat. Some European breeds, such as Embden and Toulouse, have also been used in the tropics with notable success.
DOMESTICATING GEESE
(Temperate Zones)
Today's domestic geese are descended from two species: the greylag (Anser anser) and the swan goose (Anser cygnoides). These were domesticated in Europe and China, respectively. Their domestication occurred in ancient times, long before people knew about genetics, microorganisms, veterinary science, or behavior modifications such as imprinting. Today, armed with such knowledge, more geese may be amenable to domestication. Most of the 15 other wild species adapt to captivity. Compared to most birds, geese spend much time walking and swimming and are less inconvenienced by pinioning (removing the tip of the wing). Thus, they can be kept outdoors rather than in cages.
Both of the ancestors of today's domestic geese are native to the northern temperate zone. Two more wild species that might make useful domesticates are:
- Canada goose (Branta canadensis). North America. People feeding these birds in city parks and wildlife refuges are causing many local flocks to develop. These birds no longer migrate. They are increasing in numbers each year and are well on the way to de facto domestication.
- American swan goose (Coscoroba coscoroba). Southern South America. Although most closely allied to swans in shape and physiology, this bird resembles a muscovy (see page 124) in size and behavior. Its calm disposition, as well as its attractive red feet and bill that accent its white plumage, have made it much sought as an ornament for parks.
BIOLOGY
In its diet, the goose utilizes large quantities of tender forage. It can break down plant-cell walls and digest the contents. Although it has no crop for storing food, there is an enlargement at the end of the gullet that serves as a temporary storage organ. Sand and small gravel are swallowed to aid the gizzard in grinding hard seeds and fibrous grasses. Research has shown that geese can digest 15-20 percent of the fiber in their diet, which is 3-4 times the amount that other poultry species can digest.
The natural diet consists of grasses, seeds, roots, bulbs, berries, and fruits, normally supplemented with a little animal matter (mainly insects and snails) picked up incidentally. Most feeding takes place on land. They characteristically feed for prolonged periods, even at night.
Females may lay for 10 years or more. It is generally believed that reproduction is best in the second year and that it remains good until the fifth year. Geese outlive other types of poultry; life spans of 1520 years are common.
The eggs incubate in 27-31 days. The incubation time is more variable than in most poultry species, perhaps because geese have not been subjected to the selection pressure that is imposed by artificial incubators.
BEHAVIOR
One of the most intelligent birds, the goose has a good memory and does not quickly forget people, animals, or situations that have frightened it. While personalities and habits vary among individual specimens, there are common behavioral patterns, such as the pecking order, that allow individuals to live peaceably together.
Unless conditions are crowded or there are too many males, geese normally live harmoniously both with themselves and with other creatures. The bond between male and female is strong. Changing mates is difficult, although most geese will eventually accept a new mate after a period of "mourning."
Geese nest on the ground and prefer the water's edge, but they adapt readily to man-made nesting boxes. The gander usually stands guard while the goose incubates the eggs. He then assists in rearing the goslings. Most geese become irritated if intruders approach their nest or goslings, and will even attack people and large dogs.
USES
As previously noted, these birds provide meat, eggs, fat, and down. The meat is lean, flavorful, and of outstanding quality. The fat accumulates between the skin and the flesh and can be rendered into a long-lasting oil. The eggs are large and taste much like chicken eggs. The "down" (the small, fluffy feathers that lie next to the body of adult birds) is the finest natural insulating material for clothing and bedding, and can fetch a premium price. Worldwide markets exist for both down and other goose feathers. In France, in particular, some geese are raised for their livers (foie gras).
Geese can control many types of aquatic weeds in shallow water as well as grass and some types of palatable broad-leaf weeds on the banks of lakes, ponds, and canals. They can also be used as ''lawn mowers" and "weeders" among cotton, fruit trees, and other crops (see sidebar).
Elongated necks not only allow geese to reach many different foods, they also help them keep a watchful eye on the surroundings. With their exceptional eyesight they can see great distances, and the position of the eyes gives them a wide field of vision. Geese are among the most alert of all animals, and strangers cannot calm them into silence. In the high Andes, in Southeast Asia, and in many other locations, they replace guard dogs. In Europe, they are used to guard whiskey warehouses and sensitive military installations (see page 111).
HUSBANDRY
Methods of caring for adult geese vary according to climate, breed, and people's experiences and needs. Overall, however, the birds cause little trouble and require little expense. They range freely without restriction, feeding themselves and returning home of their own accord. They have strong flocking instincts and can readily be herded from one area to another.
Like all young poultry, goslings are fragile. The highest mortality is caused by predators. Until the goslings are 6-10 weeks old, it is prudent to confine the parents and their young at night in a secure pen or building.
Geese are the only domestic fowl that can live and reproduce on a diet of grass. They cannot remain healthy on coarse dry fodder, but when grass is succulent they need little else other than drinking water. Many legumes also make excellent goose forage.
In the tropics, eggs can be laid year-round. The production seldom exceeds 40 eggs per year, although with feed supplement and simple management, the Chinese breed may yield more than 100 eggs. Geese go broody quickly. To break up broodiness, the goose can be confined for 4 6 days away from, but in sight of, the ganders.
Goslings grow rapidly and can reach market size as early as 10-12 weeks; most geese, however, are marketed at 20-30 weeks of age, when they may weigh from 5 to 7 kg, depending on type and breed. Some young birds (also called green or junior geese), force-fed for rapid growth, are marketed at 4-6 kg when they are 8-10 weeks old.
If fed a good diet to maximize growth and if slaughtered at, say, 10 weeks, the Embden, Chinese, or African will have a carcass low in fat. However, the carcass normally has much more fat than other poultry.
Geese must have a constant supply of reasonably clean drinking water during daylight hours. Although swimming water is not necessary, it promotes cleaner and healthier birds because they find it easier to care for their plumage.
DOMESTICATING GEESE
(Tropics)
Geese of the tropics have seldom if ever been considered for domestication, but they might provide poultry of considerable value. Presumably they are more heat tolerant and lack the layers of subcutaneous fat (which the ancestors of today's geese needed for warmth in the Arctic). They might thus produce lean birds that would fetch premium prices because excessive fat is the major drawback of today's commercial geese. Examples of tropical species that might be domesticable are:
- Egyptian goose (AIopochen aegyptiacus). Found throughout the African tropics, this bird is already partly domesticated. However, it is bad tempered and quarrelsome and, so far, this has limited its utility. It has therefore been kept only under semidomestication, without intensive breeding.
- Nene (Branta sandvicensis). A native of the Hawaiian Islands, this is one of the most endangered species on earth. So few specimens are in existence that farming enterprises cannot now be envisaged. Yet, should this bird prove amenable and suitable, the possibility of an economic future could boost efforts to build up its now meager populations.
- Bar-headed goose (Anser indicus). India and Central Asia. These smallish geese are handsome, dainty, and have a musical horn-like call. They have distinct black bars across the nape, which gives them their popular name. Hand-reared specimens breed well in captivity. Despite heavy hunting they are still abundant.
- Northern spur-winged goose (Plectropterus gambensis gambensis). Tropical Africa (Senegal to Zimbabwe). This large bird is a ground nester, but it has long bony spurs on the wings that enable it to easily protect its eggs and young from predators.
- Semipalmated (magpie) goose (Anseranas semipalmata). Australia and New Guinea. One of the most aberrant and primitive of all waterfowl, this long-legged sturdy-billed bird has only partially webbed feet. It perches high in trees and has a loud ungooselike whistling call.
THE WADDLING WORK FORCE
Because geese relish grasses and shun most broad-leafed plants, some enterprising U.S. farmers in the 1950s began using them to rid cotton fields of grassy weeds, which are difficult to kill with herbicides. The geese were put into the fields as soon as the crop came up. A brace of birds kept an acre of cotton weeded; a gaggle of 12 would gobble as many weeds as a hard-working man could clear with a hoe.
This method of clearing fields was so effective that by 1960 more than 175,000 geese honked their way across the carefully tended farmland, mainly in the Southwest. Seven days a week, rain or shine, the feathered field hands slaved uncomplainingly from daybreak to dusk, even putting in overtime on moonlit nights. Many toiled so diligently that they worked themselves out of a job.
The geese cleared the fields more cheaply than hoe hands. They left the crop untouched and ate only the succulent young weeds. They did not damage crop roots (as hoes or tractors can), and they were safe and selective, unlike many herbicides. On top of all that they spread fertilizer for the farmer, and ultimately provided him meat for the market.
Eventually, farmers found that geese could be used to weed nearly all broad-leafed crops: asparagus, potatoes, berry fruits, tobacco, mint, grapes, beets, beans, hops, onions, and strawberries, for example. Geese were used in vineyards and fruit orchards to eat both weeds and the fallen fruits that could otherwise harbor damaging insects. They were employed in fields producing trees for the forest industry and flowers for florists shops. Some growers turned goslings loose in cornfields to consume the "suckers" (cone, after all, is a grass) as well as the grain left on the ground. This eliminated the problem of corn as a weed when different crops were later planted in those fields.
In the 1970s when cotton acreage dropped and herbicides selective for the troublesome grasses were developed, the use of geese declined. But today, some organic farmers are returning to the practice. From February to June in the Pacific Northwest, fields are resounding once more to the old-fashioned racket of White Chinese geese.
ADVANTAGES
Mature geese are independent creatures. When kept in small flocks and allowed to roam the farmyard or field, they require less attention than any other domestic bird with the possible exception of guinea fowl. In areas where grass is green for much of the year, they can be raised on less grain or concentrated feed than any other domestic fowl.
Durability is one of their most attractive features. Along with ducks, geese seem to be the most resistant of all poultry to disease, parasites, and cold or wet weather. They also do well in hot climates as long as drinking water and deep shade are available.
Growth is not only rapid, it is also efficient. If managed properly, goslings can produce I kg of body weight for every 2.25-3.5 kg of concentrated feed consumed.
Geese are not usually thought of as prolific layers. However, as noted, some strains of the Chinese breed will yield well over 100 eggs per goose per year. At 140-170 g per egg, that compares favorably with the output of laying chickens.
LIMITATIONS
These birds are messy and their loud trumpeting is often irritating. However, unless they have been teased or mistreated or if they are nesting or brooding young, they are not aggressive. But kilo for kilo, they are stronger than most animals, and a harassed or angry adult can express its displeasure effectively with powerful bill and pounding wings.
Excessive concentrations of geese on ponds or along creeks encourages unsanitary conditions, muddies water, hastens bank erosion, and destroys plant life. Where sanitation is poor, salmonellosis can devastate geese and be transmitted, via meat and eggs, to humans. Coccidiosis and gizzard worm are other infections.
Defeathering geese is more difficult than plucking chickens because there are two coats (feathers and down) to remove.
In some situations, geese may need a diet supplement (such as grain) if they are grazing vegetation exclusively. A balance must be struck: too much supplement and they will quit foraging and become too fat; too little and they grow slowly and may suffer malnutrition.
Geese are not fully mature until two years of age. Their overall reproductive rate, therefore, is lower than that of other poultry.
RESEARCH AND CONSERVATION NEEDS
Poultry researchers worldwide should begin studies to clarify the role that geese could play in helping to feed Third World nations. Studies might include:
- Management practices for tropical areas;
- Breeding and management for increased egg production;
- Incubation techniques;
- Nutrition supplementation (for example, vitamins, minerals, energy, specific amino acids) needed by grazing geese;
- Physiology of digestion and reproduction;
- Clarifying the inheritance of various traits;
- Genetic selection for specific meat, eggs, growth factors, or disease resistance;
- Comparative studies of the relative efficiency (especially of feed utilization) of the various types and breeds for specific climates in underdeveloped countries;
- Weeding tropical crops with geese; and
- Studying diseases and cross-infection with other birds.