A nimal improvement in the tropics Written by Wuttigrai Boonkum

The Arctic The Tropics HOT, HOTTER Temperatures have risen more in the Arctic than in the tropics.

Studies trend about climate change Nowadays, biologists worry primarily about global warming’s effects on life in the Arctic

“It’s taken a while for people to start applying the thinking of climate change to the tropics” says tropical ecologist Catherine Cardelús. Hot temperature affecting creatures in the tropics

> 2010 Year 1.5 O C 0.5 O C Arctic temperature increases could double those in the tropics metabolic changes in each region’s ectotherms would still be about equivalent.

“You can’t assume that the temperature patterns tell you what the effects on biology will be”

Statistical for cow, milk and consume quantity Cow (head) Consume quantity (kg) Milk production (kg) Source: สำนักงานเศรษฐกิจการเกษตร (2550) Figure 1 Number of dairy cattle, milk production and consume quantity in Thailand

Heat stress

Why is heat stress important ? January 2003, NASA July 2003, NASA Red color is high heat area Yellow color is moderate heat area

Heat stress on physiology Department of Animal Science, Faculty of Agriculture, Khon Kaen University Heat stress pantingsweatingrespirationfeed intakeruminationwater intake

Why is heat stress important ? well-being low fertility die low feed intake low 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 to 2007, Summer was the seasons with the highest of dairy deaths (15,773) in Italy

How heat stress occur ? Cold stress Heat stress Thermoneutral zone Heat production Ambient temperature 4-24 o C Lower critical temp. Upper critical temp. humidity

Heat stress in the world ในต่างประเทศ heatv stress สำคัญแค่ไหน บอกว่าทำไมประเทศไทยถึงสนใจอิทธิพลของ heat stress รูปโลก มีแผนที่ประเทศไทย ได้รับอิทธิพลจากลมมรสุม THI > 72 for production and around 68 for reproduction are considered to indicate heat stress in dairy cattle

Heat stress in Thailand

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 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 synchronization timed artificial insemination timed artificial insemination Fertility traits

Alternative method Housing and Shading management Housing and Shading management Feed and Feeding management Feed and Feeding management Crossbreeding system x B.indicus B.taurus Temporary/non sustainable Production traits avoiding breeding during hot season avoiding breeding during hot season estrus synchronization timed artificial insemination timed artificial insemination Fertility traits Temporary/non sustainable Genetic 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 selection How heat stress affect on genetic ?

National genetic evaluation under hot-humid climates of Thailand Department of Animal Science, Faculty of Agriculture, Khon Kaen University Heat stress Rectal temperature || milk temp. || physiological responses Milk production Temperature – humidity index; THI

ปัจจัยที่สัมพันธ์ต่อการเกิด ความเครียดเนื่องจากร้อนในโคนม 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 Expected benefits : Improve genetic performance for heat tolerance Increase milk production level

National genetic evaluation under hot-humid climates of Thailand Department of Animal Science, Faculty of Agriculture, Khon Kaen University Implications : Estimated breeding value; EBV THI Threshold point Best genetic performance for milk production under heat stress conditions

Ent1 Ent2 Genetic effect Animal 1 Animal 2 Ent1 Ent2 Genetic effect Animal 1 Animal 2 No G x E interaction Reranking G x E interaction Ent1 Ent2 Genetic effect Animal 1 Animal 2 Scaling G x E interaction

Figure 2 Genetic lactation curve of top 5 sires separated by region in Thailand; all region (a), north (b), central (c), north east (d), east (e), and west (f).