Supplementation with lasalocid three times weekly to stocker cattle on pasture

Graduation date: 1987Two experiments were conducted to study the efficacy\ud of feeding lasalocid to cattle on pasture on a three times\ud weekly basis. In experiment 1, 72 crossbred yearling\ud steers were stratified across a randomized block design of\ud 12 pens including three replications of four treatments.\ud Treatments consisted of: (1) .45 kg ground corn per head\ud per day; (2) .45 kg ground corn per head three times\ud weekly on Monday, Wednesday, and Friday; (3) .45 kg ground\ud corn with 200 mg lasalocid per head per day; (4) .45 kg\ud ground corn with 467 mg lasalocid per head three times\ud weekly. Lasalocid fed everyday increased (P<.05) average\ud daily gains (ADG) by 10%. Lasalocid fed three times\ud weekly did not have a significant effect on ADG.\ud In experiment 2, six rumen fistulated heifers were\ud allotted randomly to two 3x3 Latin Squares. Heifers\ud consumed a diet of mid-bloom alfalfa hay ad libitum plus\ud the treatment supplements. Treatments consisted of: (1)\ud .45 kg ground corn per head per day; (2) .45 kg ground\ud corn with 200 mg lasalocid per head per day; (3) .45 kg\ud ground corn with 467 mg lasalocid per head three times\ud weekly. Gas chromatographic analysis indicated that\ud lasalocid fed daily or on a three times weekly basis did\ud not change the acetate to propionate ratio (P>.10). Both\ud lasalocid treatments increased (P<.05) the butyrate to\ud propionate ratio. Analysis of all C2-05 rumen metabolites\ud indicate that only butyrate was significantly affected by\ud lasalocid treatments. The addition of lasalocid on a\ud daily basis decreased (P<.05) the pH within the rumen.\ud After centrifugation, high performance liquid chromatographic\ud (HPLC) analysis failed to detect lasalocid in\ud the rumen fluid.\ud Feeding lasalocid on a three times weekly basis did\ud not appear practical based on weight gain responses.\ud Measurement of ruminal VFA and pH indicate that while\ud slight differences exist between the two lasalocid\ud treatments, they do not correlate with the lack of weight\ud gain response with animals fed three times weekly