Weather Impact Upon Performance An S 426

Weather Impact Upon Performance Been stated that for an optimum ratio of input to output for livestock should have: 1. Air temperature of 55 – 65° F 2. Relative humidity of 55 – 65 % 3. Wind velocity of 3-5 mph 4. Medium level of sunshine

Weather Impact Upon Performance Illustrated Comfort zone = the temperature interval during which no demands are made on the animals temperature - regulating mechanisms Range: 1. European beef breeds 30-60° F 2. Dairy breeds 40-60° F 3. Zeba breeds 50-80° F Critical temperature = air temperature below or above in which the metabolic rate increases to maintain constant body temperature

A-A’Comfort zone – minimal thermo-reg. C-D Body temp. drops B-B’Thermoneutrality C’-B’ Sweating & panting intensity A-BPhysical Mech. (vaso constr., piloerection)C’-D’ Body temp. increases A’-B’Physical Mech. (vaso dial., sweating panting) D-D’ Survival C-C’Homeothermy C-BRate of heat prod. increases

Weather safety can save your livestock

Weather Impact Upon Performance Wind chill chart ( O F) Wind Velocity (MPH) Temp ( O F)

Weather Impact Upon Performance Under normal and moderate conditions feed and water intake are closely related – inadequate water intake will result in cattle eating less. In extreme temperature conditions feed and water consumption are inversely related – feed intake increases with extremely cold temperatures and decreases with extremely warm temperatures.

Weather Impact Upon Performance Temperature changes have greater effect upon the digestibility of roughages than concentrates. – –Cold temperatures increase thyroid activity. Thyroid hormone increases rumen and intestinal contraction and motility. – –Since feed moves through the GI tract faster, digestibility decreases. Value of alfalfa hay: (V.G.) 86°F 68°F 23°F ME, Mcal/lb TDN, % DP, %

Weather Impact Upon Performance Summary of ISU experiments demonstrating affects of environment on feedlot performance. Effect of season and shelter on performance of yearling steers Winter Summer Shelter No shelter Daily water cons., gal ** 8.61 Daily feed cons., lb Daily gain, lb. 2.91** * 2.84 Lb. feed/lb. gain 9.15** *P <.05. **P <.01.

Weather Impact Upon Performance Feedlot performance by housing and month on test Consumption a Started on test ShelterNo shelter Confinement November January March May July September Average a Average daily feed consumption, lb. of dry matter

Weather Impact Upon Performance Feedlot performance by housing and month on test ADG a Started on test ShelterNo shelter Confinement November January March May July September Average a Average daily gain, lb.

Weather Impact Upon Performance Feedlot performance by housing and month on test Conversion a Started on test ShelterNo shelter Confinement November January March May July September Average a Average feed conversion, lb. of dry matter/lb. of gain

Weather Impact Upon Performance Carcass grades by housing and month of test Yield grade Started on test ShelterNo shelter Confinement November January March May July September Average

Weather Impact Upon Performance Carcass grades by housing and month of test Quality grade Started on test ShelterNo shelter Confinement November Choice - Choice - Choice - January Choice - Choice - Choice - March Choice - Choice - Choice - May Choice - Choice - Good+ July Choice - Choice - Choice - September Choice - Choice - Choice - Average Choice - Choice - Choice -

Weather Impact Upon Performance Summary of temperature effects on beef cattle feed and water intake TemperatureFeed intake Water intake 95° F 10-35% decrease gal./lb. of DM 77-95° F 3-10% decrease gal./lb. of DM 59 to 77° F similar to NRC gal./lb. of DM 41 to 59° F % increase gal./lb. of DM 23 to 41° F 3 - 8% increase gal./lb. of DM 5 to 23° F % increase gal./lb. of DM less than 5° F % increase gal./lb. of DM

Estimate of LCT and increase in energy requirements: Increased energy Increased hay a requirement per requirement per °F below LCT °F below LCT Wt (lb.) LCT (°F) (lb. TDN/day) (lb./day) Calf, one week old Heifer, 1.1 lb. ADG 220 dry, low wind wet, 10 mph wind Yrlg. steer, 2.2 lb. ADG 660 dry, low wind wet, 10 mph wind Dry pregnant cow, Mid third pregnancy 1100 dry, low wind wet, 10 mph wind a Hay contains 50% TDN

Estimate of LCT and increase in energy requirements: Ex. Feed dry pregnant 1100 lb. cows in a winter storm with 10 mph at -10° F LCT = 19° F, therefore conditions 29° F below their LCT [19° - (-10°) = 29°] Additional energy required =.20 lb. TDN/°F x 29 = 5.8 lb. TDN/day Since hay is 50% TDN they will need additional 11.6 lb. of hay/day (5.8 lb. TDN/day ÷.50 TDN = 11.6 lb. of hay/day)