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Summary of Orskov and McDonald Fits

Source: R/summary.orskov_fit.R
summary.orskov_fit.Rd

Summarizes parameter estimates and goodness-of-fit statistics for a fitted Orskov and McDonald model.

Usage

# S3 method for class 'orskov_fit'
summary(object, ...)

Arguments

object

An orskov_fit object.

...

Additional arguments passed to methods.

Value

A data frame containing parameter estimates and model diagnostics for each fitted bottle.

Details

The summary typically includes:

  • Initial gas volume (VF)

  • Fermentable fraction (b)

  • Fractional rate constant (k)

  • Residual Sum of Squares (RSS)

  • Root Mean Squared Error (RMSE)

  • R-squared (R²)

  • Akaike Information Criterion (AIC)

  • Bayesian Information Criterion (BIC)

The Orskov and McDonald model partitions gas production into:

  • An intercept term (VF)

  • A fermentable fraction (b)

The asymptotic gas production is:

$$ VF + b $$

The parameter k controls the rate at which the asymptote is approached.

This model is widely used in ruminant nutrition research because the parameters have straightforward biological interpretation.

See also

fit_orskov, plot_fit, plot_residuals, compare_models

Examples


files <- example_data()

raw_data <- read_ankom(
  files$ankom
)

metadata <- read_metadata(
  files$metadata
)

gp <- process_ankom(
  raw_data,
  metadata,
  headspace_ml = 210,
  temperature_c = 39
)

fit <- fit_orskov(
  gp
)
#> Warning: Large negative pressure values detected. Minimum PSI = -1.274 . Please inspect the affected bottles.
#> rumenGP data validation passed.
#> Observations: 1752
#> Heads: 24
#> Treatments: 5

summary(
  fit
)
#> 
#> Orskov and McDonald model summary
#> ---------------------------------
#> Total bottles: 24
#> Successful fits: 24
#> Failed fits: 0
#> Low R-squared (< 0.90): 4
#>