Effect of yucca (Yucca schidigera) on ammonia levels from equine excreta in the stable

摘要

Ammonia in animal waste can irritate the skin, eyes, throat and lungs of confined animals, if exposed to high levels. Thus, reducing ammonia levels in waste would be beneficial. The objective of this study was to determine the effectiveness of a yuccaproduct (De-Odorase, Alltech Inc.) on lowering ammonia levels in equine faeces. Eight horses of varying breed, age and sex (4 mares, 4 geldings; 4-18 yrs) were used in a two-period, cross-over experimental design. Animals were randomly allocated to oneof two dietary treatments with or without the inclusion of yucca at 3 g/h/d. The basal diet consisted of 0.5-1 kg of dried alfalfa plus 0.5 kg of concentrate according to animal requirements. Animals were housed over night in individual stables (12'x 12') and bedded on shredded paper. During the day, all horses were out to pasture unless they were used for work in the college. All horses had similar workloads (1-2 h of schooling and/or hacking daily). Access to water was ad libitum at all times. Ammonialevels in stables were measured between 05:30 and 07:00 daily for 7 d. Five readings were taken per stable using a Gasman single gas detector (Crowcon Ltd.) 1 m above floor level: back left corner, back right corner, front left corner, front right corner and centre. Overall, levels of ammonia were low in all stables. Nevertheless, supplementation with yucca resulted in a significant reduction (/,=0.001) in ammonia levels from 0.22 to 0.16 ppm. Addition of 3 g/h/d of yucca to the ration of stabled horses fed standard, UK diets has the potential to reduce ammonia levels, even when initial ammonia levels are low. This paper highlights one of the numerous problems that can arise in the management of performance horses. Further studies concerning the modeof action of yucca in the reduction of ammonia levels are needed.