Calculating Silage Value Of Immature Corn (continued)

September 19, 1996 3(25):146-147

Joe Lauer, Corn Agronomist

The article continues the discussion begun in the last issue of the onsin Crop Manager and uses other data describing the relationship between corn maturity and silage yield and quality

Corn silage yield and quality changed substantially during the growing season (Table 1). At V11 crude protein was 18% and one ton of silage could produce 1700 lb of milk. Like all crops, corn silage quality decreased as the crop approached flowering, i.e. milk per ton decreased from 1700 lb/T on V11-14, to 1300 lb/T on R1.0 (silking), and was lowest at R3.0 (Milk) at 700 lb/T. Milk per ton and milk per acre then increased throughout the remainder of the growing season. During the silking and milk stages, milk per acre and milk per ton was about 1/3 of the optimum harvest dates between R5.5 and R5.8.

Late planted immature corn resulted in lower yield and quality than early planted corn harvested around R5.5 (Table 2). Little grain was produced on corn planted after June 22 even with shorter-season hybrids. Milk per acre and milk per ton of immature corn was about 1/3 that of corn harvested at R5.5 to R6.

Points to consider with immature corn:

  • Immature corn is too wet to ensile and will seep out of the storage structure lowering silage quality.
  • To produce good quality silage with adequate yields, corn must be past the R4.5 to R5 stage of development. Corn which immature should be fed to heifers or other less productive animals.
Table 1. Corn silage yield and quality response to harvest date for Pioneer 3578 during 1993 at Arlington, WI. Corn was planted on May 11. Derived from Burger and Hudelson (1993) and Undersander et al. (1993).
Harvest Corn development Whole plant moisture Dry matter yield Crude protein ADF NDF Milk production
date stage % T/A % % % lb/T lb/A
                 
July 11 V11 92 1.1 18 28 49 1700 1900
July 21 V14 90 2.2 15 27 50 1700 3800
July 31 R1.0 85 3.8 12 31 55 1300 5000
August 10 R2.0 83 5.0 11 33 58 1100 5500
August 20 R3.0 84 5.7 10 36 65 700 3700
August 30 R4.0 82 6.4 10 33 60 1000 6500
September 10 R5.0 76 8.0 9 27 51 1700 13400
September 21 R5.5 75 8.6 9 25 48 1900 16300
October 5 R5.8 66 8.2 8 21 43 2300 18800
Corn development stage: Vn = nth leaf collar; R1 = Silking; R2 = Blister; R3 = Milk; R4 = Dough; R5 = Dent; R5.5 = 50% kernel milkline; R5.8 = 80% kernel milkline; R6 = Black layer (physiological maturity).

 

Table 2. Corn silage yield and quality response to planting date during 1994 at Arlington, WI. Corn was harvested near R5.5 or after a killing frost. Derived from Lauer and Hudelson (1994) and Undersander et al., (1993).
Hybrid Planting Corn development Whole plant moisture Dry matter yield Crude protein ADF NDF In vitro digest. Milk production
  date stage % T/A % % % % lb/T lb/A
                     
Pioneer 3417 May 11 R5.6 62 8.2 7 24 45 79 2100 16900
(108 d RM) May 31 R5.5 55 7.4 7 28 52 75 1600 11700
  June 22 R5.0 71 4.8 9 32 59 73 1100 5300
  July 11 R2.0 79 2.7 10 33 62 68 900 2500
                     
Pioneer 3751 May 11 R5.8 58 7.8 7 24 46 79 2000 15800
(98 d RM) May 31 R5.5 58 8.3 7 26 49 77 1800 15000
  June 22 R5.0 65 2.6 9 29 55 76 1400 3700
  July 11 R2.0 76 2.2 10 31 60 73 1100 2400
                     
Pioneer 3921 May 11 R6.0 52 6.6 7 23 44 76 2200 14200
(85 d RM) May 31 R5.6 64 6.9 7 26 47 77 1900 13000
  June 22 R5.0 66 1.3 8 33 59 69 1100 1400
  July 11 R4.0 74 2.4 10 32 61 69 1000 2400
Corn development stage: R2 = Blister; R3 = Milk; R4 = Dough; R5 = Dent; R5.5 = 50% kernel milkline; R5.8 = 80% kernel milkline; R6 = Black layer (physiological maturity).

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