Larkspur toxicosis alters basal diet intake by cattle

Objective: The objectives of this study were to evaluate (1) whether a reduction in basal diet intake occurs due to larkspur consumption, (2) how long it takes for animals to resume, to baseline, intake levels, and (3) whether there is a dose-dependent reduction of dietary intake by animals given an oral bolus dose of larkspur. Materials and Methods: Sixteen Angus heifers were housed in individual pens. Four animals were assigned to 1 of 4 treatment groups in a replicated 4 x 4 Latin square experimental design with 14-d periods consisting of a 6-d baseline period to measure feed intake and 8 d of sample and data collection. Heifers were fed once daily starting at 2.5% of BW and each subsequent day at 5% above previous day intake. On d 7, cattle were given an oral dose of a standardized amount of N-(methylsuccinimido) anthranoyllycoctonine (MSAL)-type alkaloids in the form of dried ground larkspur (Delphinium barbeyi) at 1 of 3 doses: high, medium, or low, at 8, 6, and 4 mg of MSAL-type alkaloids/kg of BW, respectively, or a control of ground alfalfa hay. Results and Discussion: There was a dose-dependent reduction of intake, with the medium treatment intake of basal diet reduced for 1 d after dosing. Animals on the high treatment reduced basal diet intake for 2 d after dosing. Implications and Applications: These results indibasal diet intakes, and it can take 2 to 3 d for animals to return to normal intake.