Impact of climate change on animal production Mohamed K.Yousef

Global warming causes climate change such as alterations in : Seasonal temperature Amount and patterns of precipitation Amount and patterns of wind velocity Extreme weather events , i.e. heat waves, storms ……………etc.

Interrelationship of climate change and livestock Livestock both Contribute to and are affected by climate change. Livestock contribute about 18 % of total greenhouse gas emissions. Climate change affects livestock production: directly (physiological , biochemical , behavioral and indirectly (changes in feed and water quality and quantity ; and disease patterns).

Anaerobic Decomposition HUMAN ACTIVITIES, INDUSTRY, TRANSPORTATION….etc. GREEN HOUSE GASES CO2, CH4, N2O REMOVAL of NATURAL SINKS OF GHG GLOBAL WARMING Rumen Fermentation Anaerobic Decomposition EXTREME WEATHER EVENTS FEED STUFF QUALITY; QUANTITY; DISEASE LIVE STOCK ANIMALS PERFORMANCE & WELL- BEING MANURE WASTE

To fully understand the impact of climate change on livestock requires : A good measures of environmental warmth Accurate measurement of thermal stress impacts on performance and well-being Assessment and prediction of occurrence of extreme weather events Development of appropriate ways for coping with thermal stress

Measure of environmental warmth “How Hot it Feels”

Meteorological Measurements Meteorological Indices for Measurement of Environmental Warmth Index Meteorological Measurements Equations Source THI Tdb, Twb =0.4(Tdb+Twb)x(1.8+48.8+32+15) Thom, 1959 (for outdoors) Tdb, RH =(0.81Tdb)+(0.143RH)+(0.0099x RHx Tdb)+46.3 Nat. Res. Council, 1971 WGBT Tdb, Twb, Tg =0.7Twb+0.2Tg+0.1Tdb Yaglou and Minard, 1957 BGHI Tg, Tdp =Tg+0.36Tdp+41.2 Buffington et al, 1981

TEMPERATURE-HUMIDITY INDEX (THI) DEAD COWS SEVERE Stress (>90) MODERATE Stress (80-89) MILD Stress (72 -79) NO Stress (<72)

Categories of the weather safety index associated with the THI (USDC Categories of the weather safety index associated with the THI (USDC.ESSA, 1970 Normal “TNZ” Alert”Mild” Danger ”Mode” Emergency “Sever”

(B) Impact of thermal stress on performance and Well-being of livestock

Animal Productivity under a wide range of environmental temperature Optimum conditions Comfort zone Low critical temp. Upper critical temp.

CATTLE SHEEP TEMPERATURE, ºC Dairy cow, dry or < 10kg milk/d -35 -30 -25 -20 -15 -10 -5 5 10 15 20 25 30 35 CATTLE Dairy cow, dry or < 10kg milk/d Dairy cow, 2wk to breeding or> 22kg milk/d Beef cow, near maintenance Calf, newborn to 2 wk Calf, 1 mo Calf, feeder, 0.8 kg daily gain Calf, feeder, 1.5 kg daily gain SHEEP Ewe, full-fleece, near maintenance Ewe, Shorn Lamb, newborn to 2wk Lamb, growing, ad-lib fed, grouped -35 -30 -25 -20 -15 -10 -5 5 10 15 20 25 30 TEMPERATURE, ºC

Is normal Tb variable ? Is metabolic rate adaptive ? Avenues of heat loss ?

Do Mammals maintain strict homeothermy ?

Premitive Homeothermy Does labile body temperature represent failure in the thermoregulatory system Premitive Homeothermy ?

50 40 30

If hyperthermia is an adaptive strategy ,How do animals tolerate high body temperature ?

Brain cooling

Is metabolc rate (HP) adaptive in mammals ? Resting HP Metabolic cost of activities , i.e, walking

Grade (%) Vertical displacement of A load in grade walking a 17 10 2 Grade status 18.4 12.7 10.2 up Man 7.1 level 3.7 5.8 6.1 Down 18.1 11.3 Burro 3.1 1.0 2.9 3.5 a= values are vertical centimeters per 100 horizontal

Avenues of evaporative water loss 1- Respiration “Painting” 2- Skin “Sweating” / “Diffusion” 3- Salivation

Relative importance of panting and sweating ? Panting Sweating Dog Man

The relative importance of panting and sweating is affected by : Degree of heat stress

2. Type of exposure to heat stress

Factors affecting panting and sweating : dehydration

Tolerance to dehydration How do animals tolerate dehydration ?

Tolerance to rapid rehydration 1. Rumen as a WATER STORE

What does control outflow of water from the rumen

2. Red blood cells tolerate a wide range of fluid osmolality

(C) Measures for thermal relief

Physical modification of the environment Housing Shade …………..etc Alteration of animal microclimate Fans Fog misters Sprinklers……..etc Improvement of nutritional and watering management techniques Change time of feeding Change quantity & quality of feeding Provide adequate water source ……etc Genetic development of less sensitive animals to thermal stress