Simpler intake estimation using direct observation in small ruminants: grouping bites by plant structure and...

Area of Science:

• Animal Nutrition
• Rangeland Ecology
• Foraging Behavior

Background:

• Accurate estimation of dry matter intake (DMI) is crucial for understanding herbivore nutrition and managing grazing ecosystems.
• Traditional methods of DMI estimation can be labor-intensive, especially in heterogeneous vegetation.

Purpose of the Study:

• To validate a novel method (M2) for estimating DMI by grouping plants based on structure and leaf morphology.
• To compare the accuracy and efficiency of M2 against a traditional method (M1) that considers individual plant species.

Main Methods:

• Utilized a dataset of 80,813 bites from 33 plant species browsed by sheep and goats in a tropical forest.
• Regrouped plant species based on morphological characteristics for M2 and compared bite weights using ANOVA.
• Estimated DMI for sheep and goats using both methods and analyzed differences with t-tests, Pearson correlation, and orthogonal regression.

Main Results:

• DMI estimations were comparable between M1 and M2 for both sheep (M1: 369±153 gDM, M2: 425±161 gDM) and goats (M1: 567±190 gDM, M2: 681±203 gDM).
• Both methods showed strong correlations, and orthogonal regression confirmed similar DMI estimations (P<0.001).
• M2 significantly reduced the workload and time required for DMI estimation in complex vegetation.

Conclusions:

• Grouping plants by structure and leaf morphology (M2) provides an accurate and efficient alternative for estimating DMI in diverse environments.
• M2 simplifies data collection and analysis, enabling the inclusion of more animals or replicates in studies.
• This method has practical implications for research and management in rangeland and forest ecosystems.