Raw data and distributions

No reason to believe calf gains differed, but it appears that calf gains in the no fire treatment came at the expense of cow performance. Cows lost weight in continuously-grazed pastures without fire, presumably because they continued to make milk to support their calves while grazing a lower-quality forage base.

Distribution of Average Daily Gains for cows and calves in 2017, by fire management treatment. Colors denote separate pastures.

Distribution of Average Daily Gains for cows and calves in 2017, by fire management treatment. Colors denote separate pastures.

Hypothesis testing

There are two different ways to ask questions of these data:

Differences among treatments

In a nutshell, cow gains on both PBG treatments are significantly different than no-fire, but PBG treatments are not different from each other:

Results of Tukey pairwise post-hoc analysis of linear mixed-effect regression comparing average daily gain across three treatments.
Coefficient SE z P
Spring + Summer - No fire 1.23 0.47 2.65 0.02
Spring only - No fire 1.19 0.47 2.55 0.03
Spring only - Spring + Summer -0.05 0.47 -0.10 0.99

Effect sizes of treatments

Gains on both PBG treatments were significantly different (greater) than zero, but gains on no-fire continous controls were not different than zero (and tended to be lower than zero).

Results of contrast tests for difference from zero on three dummy variables in a linear mixed-effect regression comparing average daily gain across three treatments.
  Sum Sq Mean Sq NumDF DenDF F value Pr(>F)
No Fire 0.66 0.66 1 11.97 3.14 0.1
Spring only 1.2 1.2 1 12.02 5.71 0.03
Spring + Summer 1.38 1.38 1 11.9 6.58 0.02
Average daily gain (lbs/day) for three treatments with associated 95% confidence intervals taken from regression coefficient estimates in linear mixed-effect regression.

Average daily gain (lbs/day) for three treatments with associated 95% confidence intervals taken from regression coefficient estimates in linear mixed-effect regression.