Larkspur toxicosis alters basal diet intake by cattle

Authors: Stonecipher, Clinton - Clint; Green, Benedict - Ben; Welch, Kevin; Gardner, Dale; Cook, Daniel

Submitted to: Applied Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/26/2023
Publication Date: 10/1/2023
Citation: Stonecipher, C.A., Green, B.T., Welch, K.D., Gardner, D.R., Cook, D. 2023. Larkspur toxicosis alters basal diet intake by cattle. Applied Animal Science. 39(5):257-263. https://doi.org/10.15232/aas.2023-02405.
DOI: https://doi.org/10.15232/aas.2023-02405

Interpretive Summary: The objectives of this study were to evaluate 1) if 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) if there is a dose-dependent reduction of dietary intake by animals given an oral bolus dose of larkspur. Sixteen Angus heifers were housed in individual pens. Four animals were assigned to one of four treatment groups 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 dried ground larkspur at one of three doses: High, Medium, or Low or a Control of ground alfalfa hay. 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 post-dosing. These results indicate that grazing animals consuming larkspur will reduce basal diet intakes and it can take 2 to 3 d for animals to return to normal intake.

Technical Abstract: Objective: The objectives of this study were to evaluate 1) if 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) if 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 one of four treatment groups in a 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 a dried ground larkspur (Delphinium barbeyi) at one of three doses: High, Medium, or Low at 8, 6 and 4 mg MSAL-type alkaloids/kg 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 post-dosing. Implications and Applications: These results indicate that grazing animals consuming larkspur will reduce basal diet intakes and it can take 2 to 3 d for animals to return to normal intake.