Agriculture Reference
In-Depth Information
Asia and northern Africa. Sheep are typically associated with marginal areas in the
grassland-based systems and as such are less productive than the humid grassland-
based systems for cattle.
Goats are also mainly found in more marginal grassland-based systems. As shown
in Figure 7.21, China and India are the two leading countries with goat populations well
over 100 million. The next five countries with large populations of goats are Pakistan,
Sudan, Bangladesh, Nigeria, and Iran. Similar to sheep, goats are produced in
grassland-based systems, often on marginal land. It is not unusual to see herds of
goats in villages being pastured along roadsides or on poor fallow fields. Goats
utilize different herbage than sheep often preferring plants rejected by other animals.
7.6.1 Biology
Sheep and goats are classified as small ruminants. Their digestive tracts are similar to
cattle and buffaloes, consisting of four chambers. Goats differ from sheep and cattle in
their method of eating and in the type of plant material they can digest. Cattle and sheep
are grazers; they eat by cutting off tufts of grass and forage plants and chewing the
stems and leaves. Goats are browsers, eating broad-leaved plants and stems of shrubs
above the ground. When sheep and goats are turned into a pasture, it is common to
see the sheep graze on grasses near the middle of the field, while the goats will roam
along the fence, browsing on weeds and shrubs. Contrary to urban legends, goats
will not eat tin cans. However, their curiosity will lead them to explore new items
with their prehensile upper lip and tongue.
Sheep are descended from the mouflon (Ovis musimon). There are two remaining
populations of mouflon in existence: the Asiatic mouflon in the mountains of Asia
Minor and southern Iran, and the European mouflon in Sardinia and Corsica.
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The
first sheep were probably domesticated over 6000 years ago. Depictions of sheep
appeared in the art of Mesopotamia and Babylon around 3000
BC
. Over the centuries,
human caretakers have selected their offspring for desirable wool, docile nature, and
flocking instinct, making them easy to care for and keep in captivity. Over 200 breeds
of sheep are recognized today. A typical wool and mutton breed is shown in Figure 7.22.
Sheep are generally grouped as either hair type or merino types. Hair sheep
comprise only about 10 percent of the world sheep population. They are most adapted
to tropical conditions because they shed hair in hot weather. They also have somewhat
lower body temperatures than merino-type sheep and are primarily raised for meat pur-
poses. Merino sheep have wool instead of hair and must be sheared each year. Wool is a
fine, curly type of hair covering the sheep. It consists of fibers of keratin covered by very
small overlapping scales. It does not conduct heat well and the crimping of the fibers
helps entrap air, making it useful for clothing in cold climates. It absorbs moisture easily.
While not normally thought of as milk animals, sheep are milked in many
countries. A typical daily yield ranges from 0.5 to 0.9 liters of milk per day during
an 85- to 110-day lactation period in Hungary.
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Specific breeds of sheep have better
milk production than others, but most sheep milk production is from multipurpose
breeds. The Awassi breed of sheep has higher milk production than many other breeds.
