Agriculture Reference
In-Depth Information
influences the mortality. Mild strains may cause only 10 percent mortality, but more
virulent strains can kill all animals in a herd. Death usually occurs within a few
days. There is no vaccination available. Infected herds are slaughtered and buried.
Attention to visitors and general herd sanitation are required.
Classical Swine Fever.
This disease was previously known as hog cholera but
the preferred name is now classical swine fever.
33
It is caused by a highly contagious
virus that can persist for years in frozen meat. The disease appears in various forms
from acute (with obvious symptoms) to chronic (with few symptoms). Symptoms
include high fever, depression, and superficial and internal bleeding. In the acute
forms there is near 100 percent mortality within 10 to 15 days after symptoms first
appear. Swine with a chronic, less severe form of the disease will also eventually
die. It is present in 36 countries around the world, being eradicated only in Australia,
Canada, and the United States. Infection is through contact with other infected
swine. This occurs mainly through auctions, livestock shows, and visitors to swine
buildings. Preventive vaccines are available and can significantly reduce the prevalence
of the disease. Infected herds must be slaughtered and buried. Normal sanitation
procedures help to prevent infection of clean herds.
7.7.4 Marketing
The primary market product from swine is meat. Incidental products are made
from the skin. Pork is usually marketed through the same marketing channels as
beef or mutton. Similar requirements exist for sanitary harvest, handling, packaging,
and transport.
7.8
AQUACULTURE
For the purposes of this section, we will define aquaculture as the rearing of aquatic
organisms under controlled conditions.
34
Within aquaculture there are many systems for controlling or capturing and rearing
aquatic animals. We will cover only two systems closely related to land agriculture:
integrated rice fields and ponds.
T A B L E 7.3. Cultivated Aquatic Animals
Finfish
Crustaceans
Mollusks
Low value
Lobsters
Clam
Carp
Crab
Mussel
Tilapia
Shrimp
Oyster
High value
Prawn
Trout
