CHARACTERIZATION OF TOXICOSIS IN SHEEP DOSED WITH BLOSSOMS OF SACAHUISTE (NOLINA-MICROCARPA)

To characterize more fully sacahuiste (Nolina microcarpa Watson) toxic osis in sheep and to evaluate benefits of supplemental Zn, sheep were dosed intraruminally with sacahuiste blossoms. In Trial 1, eight fine- wool sheep (47 +/- 2 kg BW) were fed alfalfa hay at 1% of BW daily and dosed intraruminally with inflorescences amounting to 1% of BW daily, in three portions per day, for 10 d. Four sheep were dosed intrarumin ally with aqueous ZnSO4 (30 mg of Zn/kg BW) daily for 3 d before initi al sacahuiste dosing and on alternate days thereafter, and four sheep were untreated with Zn. Toxicosis was evident within 24 h after initia l sacahuiste dosage, involving inappetence, depression, hypokalemia, h ypophosphatemia, hyperbilirubinemia, and elevated serum enzymes (alkal ine phosphatase, creatine kinase, lactate dehydrogenase, aspartate ami notransferase, and gamma-glutamyl transpeptidase). One sheep (untreate d with Zn) died on d 3. Aqueous ZnSO4 alleviated inappetence and suppr essed elevation of serum urea N and creatinine but did not suppress ot her changes in serum clinical profiles. In Trial 2, sacahuiste inflore scenses were ruminally dosed into 12 fine-wool wethers (29 +/- 2 kg BW ) in amounts equalling 0, .25, .50, and .75% of BW per day, and choppe d alfalfa hay was provided at 1.75% of BW per day for 14 d. Sacahuiste inflorescenses dosed at .75% of BW elicited severe toxicosis within 2 4 h, and dosage at .50 or .25% of BW per day increased (P = .12) serum bilirubin. Ruminal fluid pH, mean particle retention time, and partic ulate passage rate were not affected (P > .10) by sacahuiste, but rumi nal fluid passage rate increased 1.6-fold ( P < .10) and ruminal fluid volume decreased by 60% (P < .10) in sheep given inflorescenses amoun ting to .50% of BW daily. Sacahuiste inflorescenses dosed intraruminal ly at .75% of BW per day elicited ruminal impaction with severe hepato toxicosis, and dosages amounting to .50% or .25% of BW per day caused similar trends.