Drying: Water Temperature Effect on Cow Dryinging

In byandell/pda: Practial Data Analysis for Designed Experiments

Description

A dairy scientist wished to examine the effect of forage sample drying technique on ruminal disappearance of dry matter and crude protein. He gathered 30 uniquely different forage (silage) samples, roughly ten (9–11) per period. Each sample was divided each into sub-samples for drying by three different methods (microwave, freeze dryer and convection oven). There were three Holstein cows available with canulas (openings into the stomach for experimental observation), but each cow's rumen could only hold about 150 grams of forage. The scientist wanted to make sure that each sample was exposed to all nine combinations of the three cows and three drying techniques. Therefore, each drying sub-sample was further divided into 5 gram portions which were randomly assigned to the cows. The percentages of dry matter (dm) and crude protein (cp) remaining after canulation were measured, although some portions were inadvertently destroyed.

Usage

data(Drying)

Format

Drying data frame with 261 observations on 6 variables.

[,1]	cow	factor	cow identifier
[,2]	period	factor	period (1-3)
[,3]	sample	ordered	sample number per cow
[,4]	drying	factor	drying treatment (1-3)
[,5]	dmrem	numeric	dry matter remaining
[,6]	cprem	numeric	crude protein remaining

Source

Pat Hoffman

References

Drendel TR, Hoffman PC, Bringe AN and Syverud TD (1994) 'The effect of a premilking teat disinfectant on somatic cell count and clinical mastitis', Technical Report R3598, Research Division, CALS, University of Wisconsin-Madison.

Examples

data( Drying )
Drying$cow <- factor( Drying$cow )
Drying$period <- factor( Drying$period )
Drying$sample <- ordered( Drying$sample )
Drying$drying <- factor( Drying$drying )

tmpar = par( mfrow = c(3,3) )
Drying.xlim <- range( Drying$cprem, na.rm = TRUE )
Drying.ylim <- range( Drying$dmrem, na.rm = TRUE )
for( j in levels( Drying$drying ))
  for( i in levels( Drying$period )) {
    Drying.ij <- i == Drying$period & j == Drying$drying
    plot( Drying$cprem[Drying.ij], Drying$dmrem[Drying.ij],
      xlim = Drying.xlim, ylim = Drying.ylim, type = "n",
      xlab = "cprem",
      ylab = "dmrem" )
    title( paste( "drying", j, "period", i ))
    text( Drying$cprem[Drying.ij], Drying$dmrem[Drying.ij],
      interaction( Drying$sample[Drying.ij],
        unclass(Drying$cow[Drying.ij] )))
  }
mtext( "Drying Problem (sample.cow)", outer = TRUE )
par( tmpar )
rm( Drying.ij, Drying.xlim, Drying.ylim, tmpar )

byandell/pda documentation built on May 13, 2019, 9:27 a.m.