Introduction
Sheep and goats are widely adapted to
different climates and are found in all production systems. They also have
lower feed requirements compared to cattle because of their small body size.
This allows easy integration of small ruminants into different farming
systems.
Human population growth is forcing
the conversion of many former grazing areas into croplands needed for increased
food production. Raising large ruminants is becoming increasingly difficult as
a result of the ensuing lack of grazing areas. Land holdings in densely
populated areas are below 0.5 ha. In such places, the importance of sheep and
goats in fulfilling the role once played by cattle for meat, milk and manure
production is being increasingly recognized. The increased demand for sheep and
goat meat has also increased their importance in lowland pastoral areas as a
source of cash income, food security, etc.
Special
features of sheep and goats
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Feeding
behavior
Sheep and goats have different but
complementary feeding habits. Sheep are grazers and amenable to herding, hence
a species of choice in mixed cropping areas where cereal production dominates.
On the other hand, goats are browsers and highly selective feeders – a strategy
that enables them to thrive and produce even when feed resources, except bushes
and shrubs, appear to be non-existent. Thus, the presence of goats in mixed
species grazing systems can lead to a more efficient use of the natural
resource base and add flexibility to the management of livestock. This characteristic
is especially desirable in fragile environments.
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Size
Being small-sized animals, sheep and
goats require a small initial investment. Their small size, together with early
maturity, makes them suitable for meeting subsistence needs for meat and milk.
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Fat
deposition
Sheep and goats vary in fat
deposition, presumably due to different adaptation strategies. Compared to
goats, sheep lay down more subcutaneous and intramuscular fat from surplus
energy. Goats tend to lay down more internal fat, which is not associated with
the carcass. Where carcass fat is a delicacy and fetches a higher price, sheep
make an important contribution to the household economy.
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Survival
rate during drought
Sheep and goats have higher survival
rates under drought conditions compared to cattle. Moreover, because of their
reproductive rates, flock numbers can be restored more rapidly. With regard to
goats, water economy is also an important biological feature. It is common for
goats to be watered every four days and still provide a reasonable amount of
production.
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High
offtake
Due to their short reproductive
cycles (short lambing/kidding interval) and high incidence of multiple births
(particularly for some breeds such as the Horro), there is potential for a
higher annual offtake of sheep and goats than seen with cattle. This allows farmers/producers a quick
interval of selling part of their flock and generating cash income.
GOAT
Goats are multi-purpose animals,
producing meat, milk, skin and hair. Their primary function is meat production,
although in temperate countries milk has become of greater importance; skins
are a valuable by-product, especially in those countries with large goat
population. Goat meat is relished in all countries of Asia, Africa and Middle
East where there is a tradition for meat consumption from both sheep and goats. Goats constitute an important species
of livestock in Asia and contribute greatly to food, rural employment and Gross
Domestic Product.
Goat raising is one of the important
agricultural enterprise particularly in rural parts of this country and have
proved very useful to man throughout the ages, largely because of their
adaptability to varying environmental conditions under which the breeds and
strain types have evolved and in which they are maintained. They have
tremendous ability to survive, and often thrive on sparse vegetation unsuitable
for feeding of other livestock. Goats can be profitably raised with low
investment under intensive and most extensive forms of nomadic grazing. The vast majority of this poorer section of
rural population depends on goat rearing for income and certain amount of meat and
milk for home consumption. Goat rearing
requires low cost and hence suited to landless labors, marginal farmers and
industrial workers. Goats can be kept with little expense. Marginal or
undulating lands, unsuitable for other types of livestock, may be used and any
inexpensive shelter will suffice. Goat
milk is cheap, wholesome, easily digestible and nutritious. It is recommended
for use in dyspepsia, peptic ulcer and pyloric stenosis. It is preferred to cow
milk in liver dysfunction, jaundice, biliary disorders, acidosis and insomnia.
Taxonomy
Goat is perhaps the most friendly
creation of nature to mankind and its role and contribution in the developing
countries has been prominent.
Scientific
classification
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C. a. hircus
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Reproduction
Efficiency
Goats
reach puberty between three and 15 months of age, depending on breed and
nutritional status. Many breeders prefer to postpone breeding until the doe has
reached 70% of the adult weight. However, this separation is rarely possible in
extensively managed, open-range herds. Gestation length is approximately 150 days. Twins are the
usual result, with single and triplet births also common. Less frequent are
litters of quadruplet, quintuplet, and even sextuplet kids. Birthing, known as
kidding, generally occurs uneventfully. Just before kidding, the doe will have
a sunken area around the tail and hip, as well as heavy breathing. She may have
a worried look, become restless and display great affection for her keeper. The
mother often eats the placenta, which gives her much-needed nutrients, helps
stanch her bleeding, and parallels the behavior of wild herbivores, such as
deer, to reduce the lure of the birth scent for predators.
Freshening
(coming into milk production) occurs at kidding. Milk production varies with
the breed, age, quality, and diet of the doe; dairy goats generally produce
between 660 and 1,800 l (1,500 and 4,000 lb) of milk per 305-day lactation. On
average, a good quality dairy doe will give at least 6 lb (2.7 l) of milk per
day while she is in milk. A first-time milker may produce less, or as much as
16 lb (7.3 l), or more of milk in exceptional cases. After the lactation, the
doe will "dry off", typically after she has been bred. Occasionally,
goats that have not been bred and are continuously milked will continue
lactation beyond the typical 305 days. Meat, fibre, and pet breeds are not
usually milked and simply produce enough for the kids until weaning.
Male
lactation is also known to occur in goats.
Production Merits
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Meat
production
Goat meat is very popular in the
tropics, but like other kinds of meat, it is often a luxury. The special
importance of goat meat lies in its suitability for domestic consumption; for
the nomads and people of the rural areas the value of goat as a source of meat is far greater than
is usually appreciated.
In sheep the fat is distributed all
over the body, in goats visceral concentration is characteristic this in turn affects its succulence and
tenderness. Weight for weight, however, goat meat probably has higher lean meat
content. As the meat of males has a very strong taint, it is usual to castrate
males that are surplus to breeding requirements.
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Milk
Production
Although not all goats are kept for
milk production, goat‘s milk is consumed in most countries where they are bred,
and the value of milk as an important source of nutrients, particularly in
areas such as the Far East, is widely recognized.
Speicial Attributes of Goat’s Milk
Goat‘s milk has certain special
attributes which are of particular significance in human nutrition. The fat globules are small in size, friable
and the coagulum is light in comparison to that of milk from the cow and the
buffalo. These factors make it easily
digestible and explain why goat‘s milk is commonly prescribed for infants and
invalids. The casein of goat‘s milk is
also more easily digested. Moreover,
whereas cow‘s milk is acid in reaction, goat‘s milk is distinctly alkaline,
thereby making it more useful in cases of hyperacidity. The calcium, phosphorus and chlorine content
of goat‘s milk is also much higher than that of human or cow‘s milk, but its
iron content is low.
Walker (1965) has described the therapeutic uses of goat‘s milk in human
medicine. An outstanding feature about goat‘s milk in comparison with that of
other animals is that the tubercle bacillus is very rare, although it
can occur. Brucellosis, on the other hand, is fairly common, and is one of the
factors which tend to discourage wider use of goat‘s milk. However; goats are not known to be any more
susceptible than cows or pigs to brucellosis.
Efficiency
of milk production
Although there appears to be a similarity between goats, cattle, sheep
and buffaloes in the genetics of milk production, there is evidence that, in
terms of live weight, the goat is much more efficient in producing milk than
the other 3 species. In view of their lower maintenance needs in comparison
with cattle and buffaloes, and despite their relatively high metabolic
requirements, it is clear that the conversion of nutrients in milk by goats is,
in general, a more efficient process.
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Fibre
production
Goats produce two of the three types of
fibres, viz. hair, pashmina and mohair. All the hairy goats produce hair fibre,
which is utilized for preparation of ropes and gunny bags. The finest natural fibre, Pashmina , produced
by the Indian goats is either grey or white in colour. White Pashmina is preferred to grey Pashmina
due to its lustre. The shawl prepared out of such commercially superior fibres
is claimed to be so fine that it can pass through a finger ring. The goats in the hills such as Gaddi produce
hair which is used for making ropes and hair patties.
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Hides/
Skins
Skins are very valuable by-products
used mainly for leather manufacture.
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Bones
Bones major portion is utilized for
production of crushed bones and bone grists and a small quantity is used for
the manufacture of bone-meal.
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Horns and
Hoofs
Horns and hoofs constitute a very small
portion of animal byproducts but because these are rich in keratin and have
considerable value as fertilizer after conversion into meal, these have much
economic value. The horn core is particularly rich in ossein which is used in
developed countries for manufacture of gelatine.
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Meat unfit
for human consumption
Since useless meat is excellent
source of nitrogen in poultry feed and fertilizer for tea and coffee
plantations, such meat should be converted into meat meal and should not be
wasted.
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Glands and
organs
A number of biochemicals and pharmaceuticals
of importance could be prepared from the glands and organs of slaughtered
animals. Bile juice which is wasted can be collected from gall bladder and used
as raw material for preparation of bile acid and salts. Bile can be
concentrated and used in the manufacture of detergents.
SHEEP
Sheep are an important part of the global
agricultural economy. However, their once vital status has been largely
replaced by other livestock species, especially the pig, chicken, and
cow. China, Australia, India, and Iran have the largest modern flocks, and serve both local
and exportation needs for wool and mutton. Other countries such as New
Zealand have smaller flocks but retain a large international economic impact
due to their export of sheep products. Sheep also play a major role in many local
economies, which may be niche markets focused on organic or sustainable
agriculture and local food customers. Especially in developing countries, such flocks may be a part of subsistence
agriculture rather than a system of
trade. Sheep themselves may be a medium of trade in barter economies.
Scientific
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O. aries
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Reproductive
efficiency
Sheep have the potential for multiple births, especially in farm flocks.
After mating, sheep have a gestation period of about five months, and normal labor
takes one to three hours. Although some breeds regularly throw
larger litters of lambs, most produce single or twin lambs. During or soon
after labor, ewes and lambs may be confined to small lambing jugs,] small pens designed to
aid both careful observation of ewes and to cement the bond between them and
their lambs.
Measures of reproductive efficiency include
age at puberty, fertility, lambing rate, and length of breeding season.
Reproduction in sheep is strongly influenced by environment. By most estimates,
the heritability of reproductive rate is low, but breed differences exist.
Fine-wool breeds are highly fertile and have been used successfully in
crossbreeding programs to improve reproductive rate. Breeds that have been used
under intensive management systems to increase lambing rate include the Finnish
Landrace, Border Leicester, and Suffolk.
Another aspect of reproductive
efficiency is frequency of lambing. Fine-wool breeds, Dorset, and fine-wool
crossbred ewes have been used successfully in accelerated lambing programs. To
increase reproduction rate, select for number of lambs born within a given year
or frequency of multiple births. Older ewes twin more frequently than younger
ewes. This is environmental rather than genetic. The heritability of barrenness
in sheep is low. However, to maintain a high productive level within a flock,
cull ewes that fail to lamb.
Production
merits
Domestic sheep provide a wide
array of raw materials. Wool was one of the first textiles, although in the
late 20th century wool prices began to fall dramatically as the result of the
popularity and cheap prices for synthetic
fabrics. Fleeces are used as
material in making alternative products such as wool
insulation. In the 21st century, the
sale of meat is the most profitable enterprise in the sheep industry, even
though far less sheep meat is consumed than chicken, pork or beef.
Sheepskin is likewise used for making clothes, footwear, rugs,
and other products. Byproducts from the slaughter of sheep are also of value:
sheep tallow can be used in candle and
soap making, sheep bone and cartilage has been used to furnish carved items such as dice and
buttons as well as rendered glue and gelatin. Sheep intestine can be formed into sausage casings, and lamb intestine
has been formed into surgical
sutures, as well as strings for
musical instruments and tennis rackets. Sheep droppings, which are high
in cellulose, have even been sterilized and
mixed with traditional pulp materials to make paper. Of all sheep byproducts,
perhaps the most valuable is lanolin: the waterproof, fatty substance found naturally in sheep's
wool and used as a base for innumerable cosmetics and other products.
Despite the falling demand and
price for sheep products in many markets, sheep have distinct economic
advantages when compared with other livestock. They do not require the
expensive housing, such as that used in the intensive
farming of chickens or pigs. They
are an efficient use of land; roughly six sheep can be kept on the amount that
would suffice for a single cow or horse. Sheep can also consume plants,
such as noxious weeds, that most other animals will not touch, and produce more
young at a faster rate. Also,
in contrast to most livestock species, the cost of raising sheep is not
necessarily tied to the price of feed crops such as grain, soybeans and
corn. Combined with the lower cost of quality sheep, all these factors
combine to equal a lower overhead for sheep producers, thus entailing a higher
profitability potential for the small farmer. Sheep are especially
beneficial for independent producers, including family farms with limited
resources, as the sheep industry is one of the few types of animal agriculture
that has not been vertically integrated by agribusiness.
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Carcass
merits
Most of the measurable carcass
traits are medium to highly heritable, thus it is possible to improve carcass
traits through selection. It is more difficult, however, than selecting for
traits that can be measured accurately on the live animal.
Among market lambs of the same size,
carcass merit is most influenced by cutability (the ratio of lean meat to fat).
Fat is the primary factor in evaluating the carcass yield grade (measure of
cutability) and eventual value to the consumer. The amount of fat in the
carcass at a given weight is closely related to the growth curve of the lamb.
Lambs that grow rapidly and reach market weight at an earlier age generally
have a higher cutability (lower yield grade). Therefore, one practical method
of selecting for increased carcass merit is to select for rate of gain.
More exact methods of selecting for
carcass merit can be used if carcass traits of related individuals or groups
can be measured. Carcass weight per day of age, loin-eye area, fat thickness at
the 12th rib, percentage of closely trimmed retail cuts, and leg-loin index all
are used in measuring carcass merit in progeny groups. Sire progeny group
summaries can be compiled from progeny data. Ultrasound technology can be used
to estimate fat thickness and loin eye area. This technology will allow selection
for carcass merit in potential sires.
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Wool
traits
Wool can account for as much as a 20 percent
of the total gross income. Of all the economically important traits in sheep,
those related to wool are the easiest to improve. Generally, wool traits are
highly heritable and easy to measure. Traits that most directly influence the
value of a fleece include fleece weight, fiber diameter, and length of staple.
Weight of the fleece, particularly clean fleece weight, is usually the most
valuable trait. Ordinarily, clean fleece weight is associated with grease fleece
weight (actual weight of the fleece when shorn).
To increase flock wool production,
select sheep that produce the most wool. Beware, however, of selecting entirely
on pounds of wool produced because ewes that are dry or have singles rather
than twin lambs may have an advantage in wool production but not in economic
return. Milk production is negatively correlated with wool growth, particularly
when feed is limited. Keep records on lamb production and wool production.
Furthermore, if selection is placed entirely on pounds of wool, it is
conceivable that the coarser fleeces may be selected.
Staple length has an important
effect on the monetary value of a fleece. Ordinarily, this trait is highly
correlated with pounds of wool produced, and heavier fleeces typically have a
longer staple length. Measure length of staple and fleece weight at shearing
time, and select replacements based on a combination of these two economically
important traits.
The grade of a fleece is also
economically important. Fine-wool fleeces ordinarily bring higher prices per
pound than do coarse-wool fleeces. The grade, or fiber diameter, of wool
primarily depends on the breed of sheep. When selecting replacements,we should
also emphasize uniformity of grade throughout the fleece. Fleeces with a high
degree of variation in grade are undesirable and have a lower monetary value.
To detect such variation, examine fleeces of ewes and rams before shearing.
Cull ewes that have belly-type wool extending up the sides.
Other fleece traits that should be
given attention are color, softness of handle, uniformity of length and of
fiber diameter, and freedom from other defects. Cull sheep with a lot of black
fiber, hair, or kemp.
