Animal Genetic Improvement in Tropical
Area
Dr. Wuttigrai BoonkumDr. Wuttigrai Boonkum
Department of Animal Science, Faculty of AgricultureKhon Kaen University
Why is heat stress important ?
The Tropics
HOT, HOTTER Temperatures have risen more in the Arctic than in the tropics.
Why is heat stress important ?
well-beingwell-being
low fertilitylow fertility
diedie
low feed intakelow feed intake
low milk yieldlow milk yield
Economic losses
Economic impacts of heat wave on dairy industry about $1 Billion 2003 economic loss $897 to $1500 million in US
2006 California heat wave kills 16,500 dairy cows statewide>2,000 cattle died in Nebraska during June 2009
2002 to 2007, Summer was the seasons with the highest of dairy deaths (15,773) in Italy
How heat stress occur ?
Cold stress
Heat stress
Thermoneutralzone
Heat
pro
du
ctio
nH
eat
pro
du
ctio
n
Ambient temperatureAmbient temperature
4-24 oC
Lower critical temp.Upper critical temp.
humidity
Heat stress effects
THI > 72 for production and around 68 for reproduction are considered to indicate heat
stress in dairy cattle
THI > 72 for production and around 68 for reproduction are considered to indicate heat
stress in dairy cattle
How heat stress occur ?
panting
sweating
respiration
feed intake
rumination
water intake
How to reduce the effects of heat stress ?
adjustment of housing and facilities
adjustment of housing and facilities
Feed and Feeding management
Feed and Feeding management
Crossbreeding systemCrossbreeding system
x
B.indicus B.taurus
Production traits
How to reduce the effects of heat stress ?
avoiding breeding during hot conditions
avoiding breeding during hot conditions estrus synchronizationestrus synchronization
timed artificial insemination
timed artificial insemination
Fertility traits
Alternative method
Housing and Shadingmanagement
Housing and Shadingmanagement
Feed and Feeding management
Feed and Feeding management
Crossbreeding systemCrossbreeding system
x
B.indicus B.taurus
Temporary/non sustainable
Production traits
avoiding breeding during hot seasonavoiding breeding during hot season estrus synchronizationestrus synchronization
timed artificial insemination
timed artificial insemination
Fertility traits
Temporary/non sustainable
Genetic selectionGenetic
selection
What traits are interest to study?
• Using regular monthly milk records• THI information at the collecting date
Ravagnolo and Misztal, (2000)
• Using days open records
Genetic selectionGenetic
selection
How heat stress affect on genetic ?
How heat stress affect on genetic ?
Heat stress in Thailand
Stress all time
Results: Determination of heat stress threshold
Publication
Results: LSM and HI for DO
summer
winter
ปั�จจ�ยที่��สั�มพั�นธ์�ต่�อการเก�ดความเคร�ยดเน��องจากร�อนในโคนม
• Length of exposure to heat stress• Level of production• Stage of lactation• Cooling management• Feed consumption• Feed offered• Breed• cattle species• Size of the animal
National genetic evaluation under hot-humid climates of Thailand
Department of Animal Science, Faculty of Agriculture, Khon Kaen University
Implications :
Est
imate
d b
reed
ing
valu
e;
EB
V
THI
Threshold pointBest genetic
performance for milk production
under heat stress conditions
Ent1 Ent2
Gen
etic
effec
t Animal 1
Animal 2
Ent1 Ent2
Gen
etic
effec
tAnimal 1
Animal 2
No G x E interaction
Reranking G x E interaction
Ent1 Ent2
Gen
etic
effec
t
Animal 1
Animal 2
Scaling G x E interaction
Conclusions
ค่�า EBV ของพ่�อพ่นธุ์� โค่นมของกรมปศุ�สัตว์ ป� 2553
Recommended
