بسم الله الرحمن الرحيم
Physiological Responses of Heat Stress in goat
IN TAMBOUL AREA
By:
Babiker M. Babiker
Ayman A. alradi
Altraify F. Gissm Alla
and Ayman M. Ser Alkhtm.
Supervisor:
Mr. Hozifa Alsiddeg Yousif
Department of Physiology & Biochemistry
Faculty of Veterinary Medicine
Research proposal of partial fulfillment for
bachelor for Veterinary Medicine degree (B.V.M)
University of Gezira
Faculty of Veterinary Medicine
Department of Physiology & Biochemistry
February 2012
1. Introduction:
The world total numbers of goats and sheep were 861.9 and
1078.2 million, respectively, i.e. there is about one goat to approximately
1.25 sheep in the world (Faostat, 2008). There are tremendous variations among
the different parts of the world regarding the number of goats, its ratio to
sheep and their percentages. The largest number of goats is observed in Asia,
followed by Africa, representing about 59.7% and 33.8%, summing up to 93.5% out
of the total number of the world, respectively. The lowest number of goats is
found in Oceania, accounting for 0.1% out of the world total number (Faostat,
2008).
Goats play an important role in the economy of Sudanese
livelihood in rural area. Among the African countries, Sudan has the second
highest goat population estimating about 42 million. A goat occupies the third
position in terms of population size among ruminants in the country (M.A.R,
2007). The main breeds in the Sudan are Sudan Nubian, Sudan Desert, Nilotic and
Sudan Mountain goat (Taggar) (A.O.A.D, 1990).
The goat is a multipurpose animal; it produces milk,
meat, skin and fibre According to (FMAR, 2005). One of the major problems facing the goat is
the heat stress and the high ambient temperature that remains above the
thermoneutral zone for at least 8 months (Ali et al., 1999). The thermal
environment is a major factor that can negatively affect goat performance.
Increased body temperature and respiration rate are the most important signs
for heat stress in goat. The increase in body temperature is associated with
marked reduction in feed intake, redistribution in blood flow and changes in
endocrine functions that will affect negatively the productive and reproductive
performance of the goat (Abouheif & Alsobayel, 1982, 1983: Eltawill &
Narendran,1990). These physiological adjustments are essential to maintain
normal body temperature and to prevent hyperthermia (Bhattacharya & Uwayjan
1975; Al-Haidary, 2000; Lowe et al., 2001). Moreover, under these
conditions the animal’s productivity severely affected that result in a tremendous
economic loss for the breeding in goat (Hozifa, 2011).
Some livestock tolerate heat
better than others. Goat adapted to hot climatic conditions should maintain the
expression of their hereditary functional potential, during life. In other
words, animals should show least variation from the normal in traits, when
raised under such conditions. To realize this, the animals should be morphologically
and physiologically equipped to withstand an increase in heat and drought, i.e.
such traits have to assist excess body heat dissipation, as much as possible
(Habeeb et al., 1997; Marai and Habeeb, 1998). Goats tend to be less
susceptible to heat stress than swine, cattle, llamas, and alpacas. Goats tend
to tolerate heat better than sheep. Goats with loose skin and floppy ears may
be more heat tolerant than other goats. Angora goats have a decreased ability
to respond to heat stress as compared to sheep and other breeds of goats. Under
normal circumstances, livestock are able to maintain their body temperature at
a safe range, so long as they have shade and plenty of water. In extreme heat,
they will decrease their grazing time and spend more time in the shade,
especially during the heat of the day. They will graze mostly in the evening
and early morning hours. They should be allowed to rest during the heat of the
day. While heat stress (exhaustion or stroke) is not very common in goats in
temperate climates, it may occur, especially if stock are handled during the
hottest part of the day. Clinical signs of heat stress include continual
panting, rapid breathing, weakness, inability to stand, and an elevated rectal
temperature (over 105ºF/40.6ºC). If rectal temperature exceeds 107ºF (41.7ºC),
death may occur, as the animal’s cells begin to degenerate (Hozifa 2001).
Objective:
1- Test the impact
of higher temperature
on the goat.
2- To know the goats adapted to heat stress.
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