Thesis
Effect of exogenous phytase addition to diets on phytate phosphorus digestibility in dairy cows
Washington State University
Master of Science (MS), Washington State University
2004
Handle:
https://hdl.handle.net/2376/246
Abstract
The effect of adding exogenous phytase to diets of lactating cows on phosphorus digestibility was evaluated. Cows (n=16) were randomly assigned among four treatments in a 4X4 Latin square design with four periods of 28 days. Dietary treatments were: barley without phytase, barley with supplemental phytase (427 IU/kg total mixed ration, TMR), corn without phytase, and corn with supplemental phytase (427 IU/kg TMR). Phytate P in the TMR comprised about 50% of the total dietary P (0.46%). The concentration of phytate P was 10% greater (P < 0.05) in barley than in corn (0.22 vs 0.2%). Samples of feed, blood, milk and feces were collected during each 28 d period. Dry matter intake and efficiency of milk production were not affected by exogenous phytase or grain type. Milk yield and composition were unaffected by dietary phytase and grain source. The concentration of inorganic P was higher (P < 0.05) in serum of cows fed exogenous phytase (5.8 vs 6.5 mg/dL in cows fed barley diets, and 5.5 vs 6.0 mg/dL in cows fed corn diets). Using lignin as an internal marker, digestibility of phytate P was increased (P < 0.05) by the exogenous dietary phytase and total P digestibility tended (P < 0.1) to be increased. There was no effect of grain source on P digestibility and excretion of the total fecal P. Fecal excretion of phytate P was decreased (P < 0.05) in cows fed exogenous phytase. The addition of phytase to diets of lactating cows increased P digestibility and decreased phytate P excretion. In conclusion, incorporation of exogenous phytase into diets of lactating cows may have a role in P management on dairy farms.
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Details
- Title
- Effect of exogenous phytase addition to diets on phytate phosphorus digestibility in dairy cows
- Creators
- Dilip Kumar Garikipati
- Contributors
- Ronald L. Kincaid (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Animal Sciences, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525160301842
- Language
- English
- Resource Type
- Thesis