Kim, J.D.
(Yonam College of Agriculture)
,
Kwon, C.H.
(Yonam College of Agriculture)
,
Kim, D.A.
(School of Agricultural Biotechnology, Seoul National University)
Silage corn (Zea mays L) is grown extensively in livestock operations, and many managements focus on forage yield. This experiment was conducted at Seoul National University (SNU) Experimental Livestock Farm, Suwon in 1998. We determined the effect of planting date and harvest stage on forage yield ...
Silage corn (Zea mays L) is grown extensively in livestock operations, and many managements focus on forage yield. This experiment was conducted at Seoul National University (SNU) Experimental Livestock Farm, Suwon in 1998. We determined the effect of planting date and harvest stage on forage yield and quality responses of corn hybrids (five relative maturity groups). The five maturity groups (100 d, 106 d, 111 d, 119 d and 125 d) were planted on 15 April and 15 May, and harvested at maturity stages (1/3, 1/2 and 2/3 kernel milkline). Whole plant dry matter (DM) and ear percentages had significant differences among corn hybrids. Ear percentages of early maturing corns (100 d and 106 d) were higher than for other hybrids. Ear percentage at the early planting date was higher than that at the late planting date for all corn hybrids. The DM and total digestible nutrients (TDN) yields of the 106 d and 111 d corn hybrids were higher than other hybrids, and the DM and TDN yields at the early planting date were higher than that at the late planting date. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) percentages were greater for the late maturity corn hybrids. For plants of the early planting date, the ADF and NDF percentages were lower than for those of late planting date for hybrids. From the comparison among harvest stages, ADF and NDF percentages were decreased as harvest stage progressed. The TDN, net energy for lactation (NEL), and cellulase digestible organic matter of dry matter (CDOMD) were decreased as maturity of corn hybrid delayed. The TDN, NEL, and CDOMD values at the early planting date were higher than those at the late planting date among for corn hybrids. From the comparison among harvest dates, TDN, NEL, and CDOMD values were increased as harvest stage progressed. The correlation coefficient for DM percentage of grain at harvest with DM and TDN yields were 0.68*** and 0.76***, respectively. And the correlation coefficient for ear percentage with ADF, NDF, and CDOMD were -0.81***, -0.82*** and 0.73***, respectively. Our study showed differences of silage corn in forage production and quality resulting from hybrid maturity, planting date, and harvest stage. We believe that for the best silage corn, selection of the hybrid and best management practices are very important.
Silage corn (Zea mays L) is grown extensively in livestock operations, and many managements focus on forage yield. This experiment was conducted at Seoul National University (SNU) Experimental Livestock Farm, Suwon in 1998. We determined the effect of planting date and harvest stage on forage yield and quality responses of corn hybrids (five relative maturity groups). The five maturity groups (100 d, 106 d, 111 d, 119 d and 125 d) were planted on 15 April and 15 May, and harvested at maturity stages (1/3, 1/2 and 2/3 kernel milkline). Whole plant dry matter (DM) and ear percentages had significant differences among corn hybrids. Ear percentages of early maturing corns (100 d and 106 d) were higher than for other hybrids. Ear percentage at the early planting date was higher than that at the late planting date for all corn hybrids. The DM and total digestible nutrients (TDN) yields of the 106 d and 111 d corn hybrids were higher than other hybrids, and the DM and TDN yields at the early planting date were higher than that at the late planting date. The acid detergent fiber (ADF) and neutral detergent fiber (NDF) percentages were greater for the late maturity corn hybrids. For plants of the early planting date, the ADF and NDF percentages were lower than for those of late planting date for hybrids. From the comparison among harvest stages, ADF and NDF percentages were decreased as harvest stage progressed. The TDN, net energy for lactation (NEL), and cellulase digestible organic matter of dry matter (CDOMD) were decreased as maturity of corn hybrid delayed. The TDN, NEL, and CDOMD values at the early planting date were higher than those at the late planting date among for corn hybrids. From the comparison among harvest dates, TDN, NEL, and CDOMD values were increased as harvest stage progressed. The correlation coefficient for DM percentage of grain at harvest with DM and TDN yields were 0.68*** and 0.76***, respectively. And the correlation coefficient for ear percentage with ADF, NDF, and CDOMD were -0.81***, -0.82*** and 0.73***, respectively. Our study showed differences of silage corn in forage production and quality resulting from hybrid maturity, planting date, and harvest stage. We believe that for the best silage corn, selection of the hybrid and best management practices are very important.
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제안 방법
The authors are deeply grateful to the Ac^unct Professor Walter F. Wedin, University of Minnesota, fbr helpful review of this manuscript and greatly improving the grammar of a late draft of the manuscript.
The authors are deeply grateful to the Aceunct Professor Walter F. Wedin, University of Minnesota, for helpful review of this manuscript and greatly improving the grammar of a late draft of the manuscript.
The cellulase digestible organic matter of dry matter (CDOMD) followed trends similar to TDN and NEL (p<0.01), indicating that ADF percentage, which was used to calculate these values, accurately predicted hybrid difference in digestibility.
The cellulase digestible organic matter of dry matter (CDOMD) followed trends similar to TDN and NEL (p<0.01), indicating that ADF percentage, which was used to calculate these values, accurately predicted hybrid difference in digestibility. Differences among silage com in TDN, NEL, and CDOMD observed in this study appear to be similar to those of other studies (Hunt et al.
The objective of this experiment was to evaluate forage yield and quality responses of com hybrids (five relative maturity groups) to planting date and harvest stage. Correlation between DM percentage and forage yield, and quality constituents also were determined.
대상 데이터
The experimental design was a randomized complete block in a split-split arrangement with three replications.
The experimental design was a ranomized complete block in a split-split arrangement with three replications. Main plots consi마ed of com hybrids, subplots consisted of planting dates (15 April and 15 May), and sub-subplots consisted of the harvest stages 1/3 kernel milkline (ML) (GDD, l,300°C); 1/2 ML (GDD, l,380°C); and 2/3 ML (GDD, l,460°C).
Both ears and shelled com weighed. The samples were reassembled and ground through a 1 mm screen in a Wiley Mill.
데이터처리
Data were analyzed with analysis of variance (ANOVA) procedures using the SAS Statistical Software Package (1988). The mean separation among treatment means for hybrid, planting date, and harvest stage was obtained by using the Least Significant Difference (LSD) test (Steel and Tome, 1980).
이론/모형
Cellulase digestible organic matter of dry matter (CDOMD) was determined by the method described by De Boever et al. (1986).
성능/효과
DM and TDN yields were positively correlated with DM percentage of grain (p<0.001), while ADF, NDF, and CDOMD were correlated with DM percentage of the ear (p<0.001). The correlation coefficient for DM and TDN yields with DM percentage of grain were 0.
In this study, large differences among several silage com hybrids were shown in hybrid maturity, planting date, and harvest stage. Differences found were primarily in the fiber composition and ear percentage, which probably resulted in the differences in the digestibility energy that would be available to the ruminant animal.
While conventional thought is that a superior silage com must have superior forage production, data from this study suggest that com hybrids fbr silages with equal forage production do indeed have differences in nutritive value. On the basic of the findings in our study, the selection of hybrid and management practice such as planting date and harvest stage may even be more important than high production so that the effects of low fiber composition could improve animal productivity. Utilization of silage com in the field, therefore, should consider both selection of the hybrid as well as management practices.
The two energy indices chosen were net energy for lactation (NEL), which measures the amount of energy in a feed available for milk production; and TDN, which is a measure of the digestibility of nutrients contained within a feed that may be used as energy by the animal. Values for NEL and TDN were calculated from the following equations modified from Jurgens (1988) fbr com forage samples; NEL=2.
While significant differences were detected for percentage of ADF and NDF in hybrid, planting date, and harvest stage treatments, significant differences were not observed for ADL (table 6). Percentages of ADF and NDF were increased as maturity of the hybrid was delayed (p<0.
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