MINERAL-SALT SUPPLEMENT DOES NOT ATTENUATE TALL LARKSPUR (DELPHINIUM-BARBEYI) TOXICOSIS IN CATTLE

Severe livestock losses caused by tall larkspur (Delphinium spp.) cons umption have caused many producers to try various preventative measure s, including the use of mineral-salt supplementation. The objective of this study was to determine if additions or deletions of a mineral-sa lt supplement (Binn's #1 Alleviator) would alter the response (i.e,, r ate of nose pressing) of cattle to tall larkspur exposure. The dose re sponse of 5 Jersey steers was examined by systematically adding 0.25 m g of mineral-salt/kg body weight, and comparing responses in the same steers without salt supplements. Steers were then run under a variable ratio (VR) reinforcement schedule and periodically dosed with tall la rkspur at a level causing a significant decrease in responding without provoking overt signs of intoxication. Response rate with and without mineral-salt supplement was the major dependent variable; 3 to 5 ''on -off'' cycles were conducted for each subject. Steers reduced (P < 0.0 5) their rate of grain intake by 34 % during operant sessions when lar kspur was dosed compared to the previous non-dosed 3-day baseline. Rat e of nose pressing was reduced (P < 0.01) on tall larkspur dose days b y 28% vs. the 3-day non-dosed baseline. This reduction was indicative of the effects of subclinical larkspur intoxication on steers, On days when larkspur was dosed and animals were intoxicated, the addition of mineral did not alter (P > 0.1) grain intake (1.61 +/- 0.17 kg/ sessi on) compared to days when no mineral was given (1.76 +/- 0.13 kg/sessi on), On larkspur dose days (ie., when animals were intoxicated), the a verage response rates were 82.9 +/- 3.7 and 85.8 +/- 4.0 responses/min (P > 0.1) when off and on mineral, respectively. We concluded that mi neral-salt supplementation had no effect on the response of steers to doses of tall larkspur that produced subclinical intoxication.