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Intake, Digestibility, Nitrogen Balance, Rumen, and Blood Parameters of Cattle Supplemented With Acacia mearnsii
Fernanda M Dos Santos1, Leilson R Bezerra2, Jusaline F Vieira1
1Federal University of Bahia, Animal Science Department, Salvador, Bahia, Brazil.
Animal Science Journal = Nihon Chikusan Gakkaiho
|June 2, 2026
Summary
Adding Acacia mearnsii extract, rich in condensed tannins, to cattle diets reduces feed intake but enhances nutrient utilization. This study explored its effects on feedlot cattle, finding improved digestibility and altered nitrogen balance.
Area of Science:
- Animal Science
- Ruminant Nutrition
- Forage Science
Background:
- Condensed tannins from plant extracts, like Acacia mearnsii, are known to modulate rumen function and nutrient utilization in ruminants.
- Understanding the dose-dependent effects of these tannins is crucial for optimizing feedlot cattle diets.
Purpose of the Study:
- To evaluate the impact of increasing levels of Acacia mearnsii extract on feed intake, nutrient digestibility, nitrogen balance, rumen fermentation, and blood parameters in feedlot cattle.
- To determine the optimal inclusion level of Acacia mearnsii extract for improving feed utilization.
Main Methods:
- Eight rumen-cannulated bulls were assigned to a replicated 4x4 Latin square design.
- Diets included a control (0 g/kg DM) and three levels of Acacia mearnsii extract (10, 30, 50 g/kg DM).
- Feed intake, nutrient digestibility, N balance, rumen parameters, and blood metabolites were measured.
Main Results:
- Acacia mearnsii extract linearly decreased dry matter (DM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), non-fiber carbohydrate (NFC), and total digestible nutrient (TDN) intake.
- Digestibility of DM, NDF, and NFC linearly increased with extract inclusion.
- Nitrogen intake and urinary excretion decreased, while fecal N excretion increased quadratically. Ruminal pH and serum proteins linearly decreased.
Conclusions:
- Dietary inclusion of Acacia mearnsii extract up to 50 g/kg DM in feedlot cattle diets reduces feed intake.
- The extract enhances the utilization of feed and its nutrients, indicated by increased digestibility.
- Further research may be needed to balance the effects on intake and nutrient utilization, and potential impacts on rumen pH and serum proteins.
