Forage Experiment

Researcher

Tilak Dhiman, US Center for Dairy Forage

Description

The data for this problem are abstracted from a research project at the US Center for Dairy Forage. The experiment involved comparing the effects of five different diets on dry matter intake (dmi), the amount of food eaten. The animals under study were heifers (cows with their first offspring) and mature cows during the lactation (milk-producing) cycle following birth of a calf. The five diets ranged from low (diet=1) to high (diet=5) alfalfa content. The experiment was actually fairly complicated. The proportion of alfalfa for the low group began at 45% and increased to 65% over course of the lactaction cycle, while the high began at 85% and increased to 95%. However, the order of the groups (low to high) remained the same. Interest here focuses on dry matter intake for cows.

Reference

Dhiman TR, Kleinmans J, Tessmann NJ, Radloff HD and LD Satter (1995) Digestion and energy balance in lactating dairy cows fed varying ratios of alfalfa silage and grain, J Dairy Science 78, 330.

Dhiman TR and Satter LD (1996) Rumen degradable protein and its effect on microbial protein synthesis, J Dairy Science 00.

Data & Setup

forcow.dat

hc trt id code dmi

forcow.s

read data, one-factor anova, some contrasts

forage.dat

cow hc trt per dmi code

forage.s

read data, set up split plot anova

SAS Data Analysis

forcow.sas

forage.sas

forage.prt

Book Figures

forbypr.s

H: Forage Treatment by Period (Heifer or Cow)

forave.s

H: Forage Treatment on Whole Plot (Heifer or Cow)

foreff.s

H: Forage Mean Square Adjusted Effects

forprerr.s

H: Forage Residuals on Split Plots

fororth.s

H: Forage Orthogonal Residuals

forpr.s

H: Forage Treatment on Split Plots (Period)