Abstract
Several authors have shown that fiber levels can be predicted from plant height and maximum maturity in alfalfa (Medicago satvia L.). These estimates have been used to predict animal performance without any reference to error terms. This study evaluates the equations for predicting chemical characteristics from field measurements of plant morphology, and some equations for predicting animal performance from chemical characteristics. Finally, predicting forage utilization directly from field measurements of plant morphology was evaluated. Six sites were chosen from irrigated alfalfa fields in southwestern Saskatchewan. The chemical characteristics measured were neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), acid detergent lignin (ADL), ash, acid detergent insoluble nitrogen (ADIN), neutral detergent insoluble nitrogen (NDIN), and ether extract (EE). Only ADF and NDF showed predictive value from height and maximum maturity (R2 = 0.86, and R2 = 0.90, respectively). Weiss developed a theoretical model for estimating net energy based on summing the true digestibility of each of the components. This model did not predict digestibility well (R2 = 0.23). A model was developed to predict in-vitro dry matter digestibility directly from height and maximum maturity, however this model only performed moderately well (R2 = 0.61). This shows that in-vitro digestibility is predictable directly from height and maturity, although not without significant increases in error compared to prediction of ADF and NDF. Caution would be advised when using these estimates for further prediction.
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Claims 7
Claim · model-written summary
Height and maximum maturity predicted ADF with R2 of 0.86.
- Taxon
- alfalfa
Medicago sativat0 - Outcome
- ADFe0
- Value
- R2 = 0.86e0
- Qualifier
- height and maximum maturitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Only ADF and NDF showed predictive value from height and maximum maturity (R2 = 0.86, and R2 = 0.90, respectively)”
t0“alfalfa”
Claim · model-written summary
Height and maximum maturity predicted NDF with R2 of 0.90.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- NDFe0
- Value
- R2 = 0.90e0
- Qualifier
- height and maximum maturitye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Only ADF and NDF showed predictive value from height and maximum maturity (R2 = 0.86, and R2 = 0.90, respectively)”
t0“alfalfa”
Claim · model-written summary
The remaining measured chemical characteristics did not show predictive value from height and maturity.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- predictive valuee0
- Comparator
- ADF and NDFe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Only ADF and NDF showed predictive value from height and maximum maturity”
t0“alfalfa”
Claim · model-written summary
The Weiss model predicted digestibility poorly, with R2 of 0.23.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- digestibilitye0
- Value
- R2 = 0.23e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This model did not predict digestibility well (R2 = 0.23)”
t0“alfalfa”
Claim · model-written summary
A height and maturity model predicted in-vitro dry matter digestibility moderately well, with R2 of 0.61.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- in-vitro dry matter digestibilitye0
- Value
- R2 = 0.61e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A model was developed to predict in-vitro dry matter digestibility directly from height and maximum maturity, however this model only performed moderately well (R2 = 0.61)”
t0“alfalfa”
Claim · model-written summary
Direct prediction of in-vitro digestibility had significantly more error than prediction of ADF and NDF.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- errore0
- Direction
- increasese0
- Comparator
- prediction of ADF and NDFe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significant increases in error compared to prediction of ADF and NDF”
t0“alfalfa”
Claim · model-written summary
The authors advise caution when using the estimates for further prediction.
- Taxon
- alfalfaMedicago sativat0
- Outcome
- Caution would be advised when using these estimates for further predictione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Caution would be advised when using these estimates for further prediction”
t0“alfalfa”