Feeding-patch choice by red deer in relation to foraging efficiency : An experiment

Area of Science:

• Animal Behavior
• Ecology
• Nutritional Science

Background:

• Ruminants' feeding time allocation is crucial for optimizing nutrient intake.
• Foraging efficiency varies with sward characteristics like biomass and nutritional quality.

Purpose of the Study:

• To test if ruminants allocate feeding time to habitat patches based on foraging efficiency.
• To evaluate different optimization strategies (maximizing vs. matching) and null hypotheses.
• To determine the most sensitive measure of forage quality for predicting feeding behavior.

Main Methods:

• Five red deer (Cervus elaphus) were observed feeding in an enclosure with timothy grass (Phleum pratense) of varying growth stages.
• Feeding time in each treatment was recorded across seven trials.
• Goodness-of-fit tests compared observed feeding times with predictions based on digestible protein and digestible dry matter intake rates.

Main Results:

• Digestible protein was a more sensitive measure of forage quality than dry-matter digestibility.
• Feeding time distributions closely matched estimated digestible protein intake rates (R²=0.899).
• Hypotheses based on maximizing or matching intake rates were supported, while the null hypothesis was rejected.

Conclusions:

• Red deer behavior aligns with optimizing digestible protein intake.
• Forage quality, particularly digestible protein, is a key factor in ruminant habitat selection.
• Mechanistic models of intake and digestion can predict large-scale behavioral choices in ruminants.