Manure nutrient excretion by lactating cows fed exogenous phytase and cellulase

Area of Science:

• Animal Science
• Nutritional Biochemistry
• Ruminant Nutrition

Background:

• Dietary nutrient management is crucial for dairy cow health and environmental sustainability.
• Exogenous enzymes, such as phytase and cellulase, are explored to enhance nutrient utilization.
• Reducing nutrient excretion minimizes environmental impact from livestock operations.

Purpose of the Study:

• To evaluate the impact of an exogenous phytase and cellulase enzyme formulation on nutrient digestibility.
• To assess the effect of the enzyme blend on nutrient excretion in lactating Holstein cows.

Main Methods:

• Twenty-four Holstein cows were assigned to diets with or without a cellulase-phytase blend for 31 days.
• Diets consisted of corn and alfalfa silage, with specific forage, protein, and fiber content.
• Nutrient digestibility and fecal excretion were measured using acid detergent lignin as an internal marker.

Main Results:

• The enzyme formulation did not affect body weight or milk yield.
• Cows fed the enzyme blend showed reduced fecal excretion of dry matter, neutral detergent fiber, and acid detergent fiber.
• Fecal nitrogen and phosphorus excretion were significantly lower in cows receiving the enzyme formulation.
• Apparent digestibility of dry matter, fiber components, and nitrogen tended to increase with enzyme supplementation.

Conclusions:

• Supplementation with an exogenous phytase and cellulase enzyme formulation effectively reduced fecal nutrient excretion in lactating dairy cows.
• The enzyme blend shows potential for improving nutrient utilization and mitigating environmental pollution from dairy farming.
• Further research could explore optimal inclusion rates and long-term effects of such enzyme formulations.