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Grazing Corn Stalk Residue With Beef Cows. Presentation: Determining the amount of ear-drop Nutrient quality of crop residues Determining the stocking.

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Presentation on theme: "Grazing Corn Stalk Residue With Beef Cows. Presentation: Determining the amount of ear-drop Nutrient quality of crop residues Determining the stocking."— Presentation transcript:

1 Grazing Corn Stalk Residue With Beef Cows

2 Presentation: Determining the amount of ear-drop Nutrient quality of crop residues Determining the stocking rate of corn stalk residue Supplementation strategies Protein and energy Grazing strategies Effect of grazing on subsequent crop yield

3 Determining Ear-Drop 8 inch ear of corn: –Contains 0.5 lb of grain – ” ears yield one bushel (56 lb per bushel) of corn 6” ear = 2/3 of an 8” ear 4 inch ear = ½ of an 8” ear 12” ears = 1 ½ of an 8” ear

4 Determining Ear-Drop In a 30” wide row Count the number of 8” inch ear equivalents in 3 different 100 foot long strips. –Divide the number of ears by 2 to get approximate bushel per acre. Example: –Count #1 – 2 - 8” ear equivalents –Count # 2 – 1 ½ - 8” ears equivalents –Count #3 – 1 – 8” ear equivalents –2 + 1 ½ + 1 = 4 ½ 8” ear equivalents –4 ½ / 2 = 2 ¼ bushel per acre

5 Composition of Corn Crop Residue Percent DM % CP - Range % CP - Average % TDN - Range % TDN - Average Grain Leaf Husk Cob Stalk

6 Dry Matter Distribution in Corn Residue Corn Residue% Moisture % of Residue (D.M. Basis) Stalk Leaf Cob Husk

7 Composition of Milo Residue Percent DM % CP - Range % CP - Average % TDN – Range % TDN - Average Grain Leaf Stalk

8 Composition of Soybean Residue Percent DM % CP- Range % CP- Average % TDN – Range % TDN- Average Leaf Stem Pod Bean

9 Grazing Characteristics of Cows on Corn Stalks Cows are “selective” grazers on stalk fields –Select the corn first – Diet quality selected = high –Select husk and leaves second – Diet quality = medium –Select cob and stalk last – Diet quality selected = low

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11 Determining Stalk Rate of Corn Stalk Residue Residue yield related to grain yield –16 lb of dry leaf and husk per bushel of corn –Pounds of husk and leaf per acre (DM) ([bu/acre corn yield x 38.2] x bu/acre corn = 16 lb of l&h x 150 = 2400 lb DM/acre –Assume 50% available to graze (trampling etc losses)

12 Determining Stalk Rate of Corn Stalk Residue Residue yield related to grain yield –2400 lb DM/acre/2 = 1200 lb of residue per acre available –1 AUM = 702 lb of DM –1200 lb cow is 1.2 AU 1.2 AU x 702 lb = 842 lb forage DM per month for 1200 lb cow 1200 lb of l&h per acre / 842 lb for 1200 lb cow = 1.47 Months –1 ac would supply enough forage for 44 days.

13 Cornstalk Grazing Calculator

14 Supplementation Strategies for Cows Grazing Corn Stalk – Whole Field Grazing Percent Crude Protein October 22 March 22 Cow Requirement Grain Husk and Leaf Cob and Stalk Supplementation Strategy -Spring calving cows: pre-calving -Less than 1.5 bu/acre ear drop -Recommended stocking rates -None needed 1 st 30 days of grazing -Need some protein supplementation days of grazing lb of protein deficient - 3 lb/hd/da alfalfa as is lb/hd/da cube as is -65% DDG cube - after 50 – 60 days of grazing -Need protein and energy lb of protein-deficient -1.9 lb of TDN-deficient -5 lb/hd/da alfalfa as is -3 lb/hd/da cube as is

15 Supplementation Strategies for Heifers Grazing Corn Stalk – Whole Field Grazing Percent Crude Protein October 22 March 22 Cow Requirement Grain Husk and Leaf Cob and Stalk Supplementation Strategy -Spring calving heifers: pre-calving -Less than 1.5 bu/acre ear drop -Recommended stocking rates -None needed 1 st 30 days of grazing -Need supplementation - after day 30 of grazing -Need protein and energy lb of protein-deficient lb of TDN-deficient -5 lb/hd/da alfalfa as is -3 lb/hd/da cube as is -After day 55 of grazing -Need protein and energy lb of protein –deficient -2.4 lb/hd/da TDN -deficient

16 Table 1. Performance of cows that were either supplemented or not supplemented with a distillers grains based cube in late gestation while grazing corn stalk residue. SUPP CON P-value Oct. Wt, lb Feb. Wt, lb Change, Oct. - Feb., lb BCS, Oct BCS, Feb Change in BCS, Oct. - Feb Cow pregnancy rate, % Calving interval, d Calf birth wt, lb Calf weaning wt, lb a a Calf weaning weight adjusted for age of dam, age of calf, and calf sex. (Hall et al., 2008)

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18 Grazing Strategies for Cows Grazing Corn Stalk Residue Whole field grazing –Most common grazing strategy used Highest quality diet consumed early Diet quality decreases over time – corn, husk and leaf, cob and stalk

19 Grazing Strategies for Cows Grazing Corn Stalk Residue Strip Grazing –Not commonly used – more labor Diet quality is higher than whole field grazing More likely to have to haul water Risk – if you get a lot of snow, may leave corn in the field If ear drop is greater than 8 bu/acre – strip graze

20 Health Concerns for Cows Grazing Corn Stalk Residue Founder –If ear drop is greater than 8 bu/acre –If combine “spills” or over-shoots transport wagon Could add sodium bi-carbonate to water – 2.5#/100 gal Nitrates usually not a problem –Total nitrate intake = forage(s) + water (additive) Provide fresh water at all times

21 Effect of Cows Grazing Corn Stalk Residue on Subsequent Grain Yields Grazed and non-grazed ridge-tilled and conventional cropping systems: - No difference in corn grain yield - 1 in 3 year, 8% reduction in soybean yield - Year 3 – ground not frozen * Concern if conditions are muddy - March

22 Grazing Genetic Modified Corn Bt-corn (corn root worm protected) and RR hybrids: –Grazed with spring-calving cows No effect on cow performance

23 Questions


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