Levels Of Monensin Research Articles

Levels of Monensin with and without Tylosin for Growing-Finishing Steers

Levels of Monensin with and without Tylosin for Growing-Finishing Steers

Anticoccidial Activity of Salinomycin in Floor-Pen Experiments with Broilers

The anticoccidial agent salinomycin (AHR-3096) was compared at various treatment levels (60 to 100 p.p.m.) in two experiments against unmedicated and either 100 or 121 p.p.m. monensin-medicated groups to evaluate its performance under floor-pen conditions. Various methods for the initial rearing of birds and coccidial exposure were employed to test the efficacy of salinomycin against severe, moderate, and mild coccidiosis. Salinomycin at all treatment levels showed definite anticoccidial activity resulting in improved weights, feed conversion ratios, lesion scores, and mortality compared with unmedicated controls. In pens with severe coccidiosis, this compound demonstrated a significant improvement in all parameters when compared with the corresponding unmedicated controls. Salinomycin-treated pens exposed to light coccidiosis usually had a numerical increase in the parameters over the unmedicated control groups. Statistical analysis of overall main effects on mortality, weight gain, and feed conversion ratio showed no significant differences between the activity of any level of salinomycin and monensin.

Effects of Monensin-Feeding Regimens on Flock Immunity to Coccidiosis

Feed medication with monensin caused delays in development of immunity in two floor-pen experiments which simulated commercial broiler production. Development of immunity was retarded with the higher level of monensin (120 p.p.m.) but was progressively less delayed as the monensin level was decreased (100, 60 or 0 p.p.m.). Delay was greatest with Eimeria tenella, but also occured with intestinal species including E. acervulina, E. brunetti, E. maxima, E. mivati, and E. necatrix. Drug withdrawal permitted earlier development of immunity. Plans involving use of monensin on layer replacements which later will be maintained on the floor without medication should consider: 1) prevalence of infective oocyst exposure in the area, 2) the lowest possible level of drug required for protection, and 3) its use for the shortest possible period of time.

Effect of Monensin on Gains of Steers Grazed on Coastal Bermudagrass

A 140-day grazing trial was conducted to determine the effects of various levels of monensin on gains made by steer calves and yearlings while grazing Coastal bermudagrass pasture. Cattle on all treatments were grazed on Coastal bermudagrass forage at a stocking rate of 2.5 head per acre (6.2 steers per hectare). Corn, yellow, grnd., pelleted, 4 02 992 (ground, pelleted corn) was fed at a rate of 2 lb (908g) per head daily as a carrier for the appropriate monensin levels. The treatments were no corn, corn only, and corn plus 25, 50, 100, or 200 mg monensin per head daily. Each treatment was replicated twice. Ten cattle, with equal numbers of steer calves and yearling steers, were grazed in each replicate. The cattle were rotated among pastures within each set of replicates at 7-day intervals. Cattle on all levels of monensin produced larger (P<.05) weight gains than the control cattle. Animals fed corn with no monensin performed better than those on forage only. Growth rates of the steers receiving monensin increased as the drug level increased through 100 mg per head daily. Cattle fed the 200 mg level of monensin gained only slightly, but significantly, more than those on the 25 mg level.