PM
Crude protein (CP) and starch are important parameters depending on the end-user’s needs, Bell said. CP and starch levels were directly related to SCA damage and declined with greater damage due to to a lack of grain development.
Quality loss continues “When evaluating the quality after ensiling versus the quality of the forage at harvest, we found that ensiling did not stabilize quality parameters,” Bell said. “Following an ensiling duration of 60 days, there was a significant reduction in lignin, IVTDMD, CP, and starch levels, indicating forage quality was not stable during the ensiling process.” The reduction in lignin, IVTDMD, CP, and starch may have been affected by the chop length of the forage. At damage ratings greater than 4, the forage chop length was not uniform. Irregular and long chop lengths do not pack well and trap oxygen, which can result in aerobic instability during the fermentation process and quality degradation. Calculated indices of forage quality (TDN, milk per ton, and RFQ) were not statistically different after ensiling for 60 days, she said. However, as with the fresh forage, quality indices also dropped as damage levels rose from 4 to 8.
pH, when compared to the other insecticide treatments. “The results show that the level of damage SCAs cause to yield during the milk developmental stages to harvest impacts the quality of the forage sorghum,” Bynum said. “Since populations can develop rapidly, the study concluded SCAs should be controlled to prevent damage during the flowering and early grain developmental growth stages.” Ultimately, the quality of the silage is as good as the quality of the harvested forage, Bell said. When managing forage sorghums, timely SCA control measures are necessary in regions with sugarcane infestation to maintain fresh and ensiled forage sorghum quality. •
While forage quality is a concern for livestock feeders, farmers directly selling forage sorghum silage are more interested in the economic return of the fresh chopped forage, Bell said. If damage levels were greater than or equal to 6 by the soft dough growth stage, there were no losses in yield or economic return. However, when damage levels were 7 to 10, there was a progressive loss in yield and a substantial loss in the economic return. Bell and Bynum said the impact of SCA feeding damage to the forage silage quality components were similar to the losses related to yield. The forage quality in the untreated and Warrior treatments had statistically significant differences for all of the ensiled components, except CP and
Effects of SCA damage on forage sorghum yield 35 30
Beginning milk Sept. 1, 2017
25 20 15 10
y = -2.2794x + 29.476 R2 = 0.8163
5 0
0
1
2
3
4
5
6
7
8
9
10
Texas A&M High Plains SCA/ damage rating scale
Mean value for each forage quality component by treatment and ensiled days % (Dry matter basis) Lignin
Starch
ADF
IVTDMD48
Milk per ton
RFQ
Untreated
TRT
8.49 c
6.1 a
11.6 b
41.5 a
70.2 b
48.5 b
2,625.4 b
76.9 b
Warrior II 1.92 oz.
8.7 bc
5.72 a
13.7 b
39.6 a
72.8 b
51 b
2,781.9 b
85.2 b
Lorsban Advanced 16 oz.
CP
TDN
9.25 abc
5.11 b
22.7 a
33.5 b
77.9 a
57.4 a
3,188.5 a
111.4 a
Sivanto 1 oz.
9.1 abc
5.1 b
25 a
32.6 b
80.3 a
58.9 a
3,278.4 a
121.7 a
Sivanto 5 oz.
9.19 abc
5.1 b
25.3 a
31.8 b
78.8 a
58.8 a
3,273.5 a
118.5 a
Sivanto 7 oz.
9.6 a
5.07 b
21.6 a
32.9 b
79.3 a
58.4 a
3,243.1 a
118.1 a
Sivanto 10 oz.
9.49 ab
4.98 b
22.8 a
32.2 b
79.7 a
59.5 a
3,327.4 a
122.4 a
ADF
IVTDMD48
TDN
Milk per ton
RFQ
% (Dry matter basis)
Ensiled days
CP
Lignin
Starch
0
9.49 a
5.5 a
23.4 a
35.6 a
77.9 a
55.9a
3,089.4 a
108.087 a
60
8.75 b
5.1 b
17.4 b
34.2 a
76.1 b
56.2 a
3,115.8 a
107.376 a
a
Means in each column for treatment and ensiled days with the same letter are not significantly different. Tukey-Kramer method for multiple mean separation (P > 0.05).
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