Impact of Weather on Feedlot Management

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Impact of Weatheron Feedlot Management
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Adverse Weather Environment Stressors In
Feedlot Cattle

• Hot weather
• Cold weather

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HOT WEATHER

• What is considered too hot for feedlot cattle?
• How do we recognize an animal suffering from heat
  stress?
• What actions can we take to prevent heat stress?
• Why do we care?

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Effective Ambient Temperature

• Air temperature
• Solar radiation
• Air movement
• Contact surfaces
• Precipitation

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HOT WEATHER

• THI Index
• temperature/humidity
• origin Thom 1959
• first developed for humans
• Formula
• Temp (0.55 (0.55 x (RH/100))) x (Temp 58)

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THI INDEX CATEGORIES

• Alert (THI 75-78)
• Additional precautions, prepare for ? T
• Danger (THI 79-83)
• Dangerous to confined livestock, additional
  measures should be taken to avoid severe losses
• Emergency (THI 84gt)
• Consider changing livestock handling and
  shipping plans

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Heat stress signals

• Body alignment with solar radiation
• Shade seeking
• Refusal to lie down
• Reduced feed intake
• Crowding around water source
• Agitation and restlessness
• Reduced or ceased rumination
• Bunching
• Open mouthed labored breathing
• Inability to move
• Collapse, convulsions and coma
• Physiological failure and death

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Prevention is ALWAYS better

• Which cattle are most at risk?
• Provide cattle most susceptible to heat stress
  with east sloping lots and lots with most shade
• Monitor effective temperature temperature,
  humidity, wind solar radiation
• Maintenance requirement increases
• Rapid shallow panting - 7
• Open-mouth panting - 11 to 25

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Prevention is ALWAYS better

• Take precautions under extreme conditions
• additional water
• sprinkling
• mounds
• shade

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Mean ambient temperature (degrees celsius),
relative humidity (percentage) and
temperature-humidity index.
Time (hours)
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Rectal temperature of steers exposed to hot
conditions.
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Research Reports on SprinklersUsed when air
temp. above 80 F
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Sprinkling

• When should you begin sprinkling?
• How much water should you use?
• Where is the best place for the sprinkler?
• What type of sprinkler

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Mounds

• Why use mounds?
• Water application
• How much is too much
• When to apply

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Shade

• Reduces exposure to solar radiation
• reduce heat load
• Construction considerations
• Orientation
• Space
• Height
• Roof

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Shade - construction

• Orientation
• East/west ground cool under shade, greater
  percentage shadow under shade than north/south
• North/south less effective, minimize mud

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Shade - construction

• Space
• 20 to 40 sq. ft. per animal dont overcrowd
• Height
• 8 to 14 ft. keep in mind air movement
• Roof effective is reflective
• white colored, galvanized or aluminum materials

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Shade - summary

• Enhance natural ventilation
• - site should have minimal trees
• - minimal buildings or obstructions within 50
  ft. on all sides
• Whether benefits from shade justify cost depends
  on the year and degree of heat stress
• Insurance Peformance benefits are bonus

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July 29, 1999 Heat Wave

• Death loss in NE 5,000 hd
• Death loss in SW Iowa 100 hd
• Why the difference?
• Emergency plan in place
• Memory of 1995
• Wind speed on July 29, 1999
• Acclimation of cattle week of July 25, 1999

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July 11 12, 1995

• High Temperatures
• High Humidity
• No Wind
• Deadly Combination

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July 11 12, 1995

• 13 West Central Iowa counties
• Market 323,300 HD/year
• Estimates 50 on feed 161,650 HD
• 3750 HD dead
• 2.32 death loss
• 2.8 M cattle losses
• 28.0 M production losses

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Weather History

• Combination of heat humidity of July 11, 1995
  was matched only 5 previous times in 101 years of
  Iowa weather history
• Aug. 3, 1930
• Aug. 6, 1918
• Aug. 17, 1913
• July 26, 1894
• July 27, 1894

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Weather Conditions July 11 12

• High 104 F
• 50 Relative Humidity
• Calm winds after 3 to 5 P.M.
• No cloud cover
• Predicted high low 90s

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Cold Weather

• What is too cold?
• Response to cold stress
• What can we do to reduce cold stress

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Lower Critical Temps
Newborn pigs, single
Newborn pigs, group
1040F
Hogs, growing
860F
Pregnant sows Newborn calf
680F
Lactating sow
500F
110-440lb growing calf
320F
Yearling cattle, pasture
140F
Growing cattle, confined
-40F
Finishing Cattle
-220F
-400F
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Lower Critical Temps
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Performance responses

• Maintenance requirements increase gt24
• Feed intake increases
• Poorer gains and feed efficiency
• gains depressed by ½ lb or more in Jan
• one lb more feed required per lb of gain

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Physiological responses

• Maintaining core body temperature
• Bunching together
• Increase in intake
• Blood flow
• away from extremeties
• less heat loss

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Remember

• Whatever is an advantage in cold stress is a
  disadvantage in heat stress
• Pens that are best for light calves in the winter
  are not for finished black-hided cattle in the
  summer
• Wind is bad in the winter and is good in the
  summer

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Management considerations

• Keep snow out of the bunks
• Top priority
• Snow not removed cattle turn it to ice
• Reduced/erratic intake
• Feed trapped in snow/ice
• Difficult to obtain accurate bunk read

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Management considerations

• Scrape ice and snow off the apron
• Build up on concrete
• Difficult for cattle to access bunk
• Reduced intake
• Reduced performance

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Management considerations

• Dont limit water
• Water intake correlated to feed intake
• Water freezing at night and not during the day
• Cattle may want to drink at night
• Competition for water space
• Reduced performance

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Water intake (1000lb BW)
Note Ingesting ice or snow requires more heat
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Management considerations

• Dont overfeed
• Keep bunks clean and the feed fresh
• Dont get ahead of the cattle
• Intake fluctuations reduced
• Dont use feeds/commodities poor quality
• Cattle can adapt to different/novel feeds
• Moldy, musty or unpalatable (? intake)
• Periods of cold stress not the time to change
  diet composition

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Management considerations

• Avoid feeds freezing in the bunk
• Silage backgrounding diets
• Wet finishing rations
• Multiple feeding
• ? DM content by adding drier feeds
• Additional roughage
• How much?
• 1-3 increase (particularly diets 7-9 roughage)

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Shelters

• Allow cattle to get out of the wind and provide
  some protection
• Ensure that your shelter does not trap snow
• Whatever helps in winter is potential risk in
  summer

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Open front shed during blizzard Jan 98
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Cold weather - Summary

• Most problems are storm related
• Beware cattle tend to tank up prior to and
  during early part of storm
• Multiple feeding
• Increase roughage (storm ration)
• Most vulnerable cattle in protected pens