[Studies on the effect of phosphoric phenyl ester diamide as inhibitor of the rumen urease of dairy cows. 1. Influence on urea hydrolysis, ammonia release and fermentation in the rumen].
An amount of 0, 0.1, 0.5 and 1.0% (related to N) of phosphoric phenyl ester diamide (PPD) effective as urease blocking substance was applied to the surface of urea with oilbitumen and fed to cows with rumen cannulae over a period of 31 resp. 164 ... 167 days. (The ration essentially consisted of 4.5 kg dried roughage and 1.5 kg starch or 1.1 kg starch plus 0.4 kg sugar and contained 50 g urea). By treating the urea with PPD, the activity of urease, the hydrolysis rate of urea and the NH3-concentration in the rumen were significantly diminished 0.5 to 2 hours after feeding (alpha = 0.05). The effect of PPD was greatest in the first days and decreased with the advancing feeding period. In the variant with 0.5% PPD the examined parameters were significantly reduced after 142 to 164 days, too. This effect remained traceable in its diminished form even after the preparation was discontinued over a period of 35 days. The dynamics of the NH3-concentration was not altered by PPD after a longer feeding period. One can conclude that PPD inhibits the hydrolysis of urea but does not retard it. In conclusion one can say that, because of PPD, the toxicity of urea is lower without the utilisation of urea being better. Due to PPD the molar propionate level in volatile fatty acids decreases significantly and the acetate-propionate relation is expanded.
D000641:Ammonia / Q000378:metabolism; D000821:Animal Feed; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D003612:Dairying; D005285:Fermentation; D010755:Organophosphates / Q000494:pharmacology*; D009943:Organophosphorus Compounds / Q000494:pharmacology*; D012417:Rumen / Q000187:drug effects / Q000378:metabolism*; D014508:Urea / Q000378:metabolism; D014510:Urease / Q000037:antagonists & inhibitors
D010755:Organophosphates; D009943:Organophosphorus Compounds; C032022:phosphoric phenyl ester diamide; D000641:Ammonia; D014508:Urea; D014510:Urease
Untersuchungen zur Wirkung von Phosphorsäurephenylester-diamid als Inhibitor der Pansenurease bei der Milchkuh. 1. Mitteilung: Die Beeinflussung von Harnstoffhydrolyse, Ammoniakfreisetzung und Fermentation im Pansen.