Effect of Environment on Nutrient Requirements of Domestic Animals (1981) / Chapter Skim
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BEEF CATTLE
BEEF CATTLE
Pages 59-74
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From page 59... ...
Where information is available, consideration is given to nonthermal stress factors as well as to protein and other dietary components. In developing adjustment factors, it has been necessary to assume that the recommendations contained in Nutrient Requirements of Beef Cattle are for cattle exposed to conditions relatively free of thermal stress or an ambient temperature range of about IS to 25°C.
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From page 60... ...
The last is really two components, one associated with longer-termed acclimatization to thermal stress and the other TABLE 12 Summary of Voluntary Food Intake of Beef Cattle in Different Thermal Environments Thermal Environment Intakes Relative to Values Tabulated in Nutrient Requirements of Beef Cattle ~ 35°C 25' to 35°C 15 to 25°C 5 to 15°C -5 to 5°C Marked depression in intake, especially with high humidity and/or solar radiation and where there is little night cooling. Cattle on full feed-10 to 35 percent depression.
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From page 61... ...
VOLUNTARY FOOD INTAKE In general, voluntary intakes of food tend to decrease as ambient temperature increases and increase when ambient temperatures decrease. Tables 12 and 13 provide summaries of changes in voluntary food and water intake due to various stressors and are presented relative to the estimated dry matter intakes tabulated in Nutrient Requirements of Beef Cattle.
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From page 62... ...
, and T = effective ambient temperature (°C)
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From page 63... ...
Presently, no adjustment is recommended for concentrate diets fed to beef cattle. ADJUSTMENTS TO MAINTENANCE ENERGY REQUIREMENT Thermal environment influences maintenance energy requirements of cattle two ways: first, that due to acclimatization as a consequence of prolonged exposure to a thermal environment, and second, that due to an immediate increase in heat production necessary for maintenance of homeothermy when the animal is exposed to an acute heat or cold stress.
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From page 64... ...
An alternative exists to adjusting maintenance requirement by the above equation and then having to calculate adjusted NEm values for tables in Nutrient Requirements of Beef Cattle. Adjustments can be made directly to the NEm and maintenance energy requirement values expressed in terms of ME or TDN by decreasing (for heat)
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From page 65... ...
. Often more important than the immediate increase in energy requirements during a severe cold stress, such as from a winter storm or blizzard, can be the challenge to animal survival.
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From page 66... ...
, LCT = lower critical temperature (°C) , T = effective ambient temperature (°C)
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From page 67... ...
As an example, the dietary energy requirements of cattle increase to compensate for the increased heat production during cold exposure, but do protein, mineral, and vitamin needs increase proportionately? There is some evidence that vitamin
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From page 68... ...
r~ ~u ~ ~ ___ _ ~ ~ oo ____ _ ~ ~== oo oo ~a~ o o o o o o o ~o o o o o o _ _ -, {+, ~ ~, , ~ c = <~ .= ~ 3 ~ .~: ~ 3 - cL.
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From page 69... ...
Adjust by either the NEm equation or the percentage factor method the maintenance energy requirement estimates for animals tabulated in Nutrient Requirements of Beef Cattle downward 0.91 percent for each °C cattle have prior exposure to seasonal temperatures above 20°C and upward 0.91 percent for each °C below 20°C, see page 64.
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From page 70... ...
oc z ~: 'e z oo m C~ .
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From page 71... ...
b. A hot dry environment with an average ambient temperature of 30°C, but where for a short duration daily mean temperatures rise to 35°C, resulting in rapid shallow breathing.
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From page 73... ...
x. A hot dry environment with an average ambient temperature of 30°C, but where for a short duration daily mean temperatures rise to 35°C resulting in rapid shallow breathing.
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From page 74... ...
~ Go ~ _I ~ o ~oo oo .
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