Agriculture Reference
In-Depth Information
The effects of diseases and parasitic infection are infl u-
enced by host, management, and disease/parasitic agent
factors. With these factors in mind, this chapter will
provide and discuss basic information on the most common
diseases and parasitic infections that may be encountered
with some rational integrated control measures for sustain-
able production.
Table 11.1
Normal values for most vital signs in
goats.
Rectal temperature
39 - 40 ° C (103 - 104 ° F)
Pulse or heart rate
Adult
70 - 90 beats per minute
Kid or stressed animal
Double the adult heart rate
Respiratory rate
12 - 20 breaths per minute
Rumen contractions
1 - 2 contractions per minute
HEALTH AND DISEASE
Health and disease are diffi cult to defi ne because although
they are at opposite poles of the spectrum, they represent
a continuum from one to the other. For example, a goat in
“excellent” health may still have parasites (a disease). For
the purpose of this chapter, health is defi ned as the state of
being that allows sustainable, optimum productivity;
disease is defi ned as the state that prevents optimal pro-
ductivity. Thus, all factors that improve health must be
promoted, and everything that inhibits it must be opposed.
Health is a state of harmonious well-being, while disease
is a lack of equilibrium.
Within this broad defi nition, the cause of disease can be
divided into the
essential
causes of disease (the part that
is central and is impossible to replace such as an infectious
organism or nutritional defi ciency), and the
suffi cient
causes of disease
(the contributory factors that make the
disease occur, such as transmitters of diseases or manage-
ment practices). Without this understanding, the manage-
ment of diseases is bound to fail because both central and
contributory factors are necessary to cause disease, and
both must be addressed to effectively treat and prevent
disease. By understanding the central and contributory
factors, diseases can be tackled in a holistic and consistent
manner, and simultaneously all signifi cant matters involved
can be addressed.
Rumen contractions
durations
10 - 15 seconds
The FAMACHA test is a goat-side test that allows
approximation of the animal's packed cell volume (PCV).
It is performed by everting the lower lid of the eye and
examining the color of the conjunctival mucosa (mucous
membrane). In general, pale or white membranes correlate
with varying degrees of anemia, which correlate well with
the burden of blood-sucking parasites (
Haemonchus
contortus
).
These observations are part of a minimal database that
will be an important aid in establishing the nature of
disease. These measurements should be made repetitively
and recorded, which over time will allow determination
of improvement or exacerbation of the underlying
condition.
IMMUNITY AND IMMUNIZATION
Animals can become immune (resistant to infection,
disease, or unwanted biological invasion) either by
inher-
ent
or
acquired
resistance to a disease. Inherent immunity
does not require previous exposure to an infection (that is,
goats are inherently immune to most equine diseases). The
development of acquired immunity requires exposure to
the antigen that causes a disease. Acquired immunity is of
two types:
active
and
passive
. Passive immunity is acquired
by the absorption of preformed antibodies. Examples
would include a kid consuming colostrum, which contains
antibodies produced when the doe was exposed to antigens
or by injecting a goat with Tetanus Antitoxin (TAT),
which contains antibodies that were produced by a horse
exposed to tetanus antigen.
Passive immunity is short lived, usually lasting 2-3
months after birth; however, active immunity is much
longer lasting, often several years or even lifelong. Animals
develop active immunity if they survive
natural exposure
to an infectious agent. However, this can be accompanied
by severe disease and production loss. They can also
PHYSICAL EXAMINATION
Physical examination includes general observation of the
animal or fl ock from a distance followed by restraint of an
individual animal and in-depth examination. Physical
examination also includes the careful collection of the
animal's signalment (age, sex, and breed), a historical col-
lection of information concerning the past history of the
animal and fl ock, and the history and clinical signs associ-
ated with the immediate medical complaint.
Normal Values
Normal values for most vital signs for goats are presented
in Table 11.1 and may vary considerably depending on
animal activity and environmental conditions.
