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Exogenous β-mannanase improves feed conversion efficiency and reduces somatic cell count in dairy cattle
T A Tewoldebrhan1, J A D R N Appuhamy1, J-J Lee2
1Department of Animal Science, University of California, Davis 95616.
Journal of Dairy Science
|March 26, 2017
Summary
Supplementing lactating dairy cows with β-mannanase at 0.1% of dry matter improved feed conversion efficiency and reduced somatic cell count. This enzyme supplementation enhanced milk production per unit of dry matter intake without negatively impacting milk yield or composition.
Area of Science:
- Animal Science
- Nutritional Biochemistry
- Enzyme Technology
Background:
- Exogenous fibrolytic enzymes, such as β-mannanase, show potential for improving feed conversion efficiency (FCE) in livestock.
- While extensively studied in nonruminants, the effects of β-mannanase supplementation in ruminants, particularly dairy cows, require further investigation.
Purpose of the Study:
- To evaluate the impact of β-mannanase supplementation on nutrient digestibility, FCE, and nitrogen utilization in lactating Holstein dairy cows.
- To determine the optimal dosage of β-mannanase for improving dairy cow performance.
Main Methods:
- A 3×3 Latin square design was employed with 12 multiparous Holstein cows.
- Cows were fed a basal diet supplemented with three levels of β-mannanase: 0% (control), 0.1% (low supplement, LS), and 0.2% (high supplement, HS) of dry matter.
- Nutrient digestibility, feed intake, milk yield, milk composition, and nitrogen utilization were monitored over 18-day periods.
Main Results:
- The low supplement (LS) dose of β-mannanase (0.1% DM) reduced dry matter intake but increased milk produced per kg of dry matter intake by 90g.
- Somatic cell count (SCC) in milk was significantly lower in cows fed the LS diet.
- The high supplement (HS) dose did not yield significant changes in milk yield, DMI, SCC, or nutrient digestibility.
- Despite reduced crude protein digestibility with LS, nitrogen intake reduction led to similar fecal nitrogen excretion; however, milk protein nitrogen partitioning improved.
Conclusions:
- Supplementation of β-mannanase at 0.1% of dietary dry matter effectively improves feed conversion efficiency and reduces milk somatic cell count in lactating dairy cows.
- This dosage enhances milk production efficiency without adverse effects on milk yield, composition, or overall nitrogen excretion.
- Further research may explore higher dosages or different enzyme combinations for potentially greater benefits.
