The Effects of Chlortetrocyline and Ethomid C/15 on Growth, Apparent Digestibility and Blood Levels of Urea and Total Non-Protein Nitrogen in Young Dairy Calves

Abstract

Eighteen new-born dairy calves were used in studies to evaluate the effect of an aureomycin (chlortetrocycline) supplement and a surfactant, Ethomid C/15 (Polyoxyethylene cocoamide), on growth, feed utilization, apparent digestibility and blood levels of urea and non-protein nitrogen. The calves were raised to 86 days of age on a limited milkstarter-hay system. The control calves gained 0.99 lb. daily whereas those fed aureomycin gained 1.26, and those fed Ethomid C/15, 1.16 lb. daily. These differences were statistically significant. An improvement in feed efficiency and a lowering of the incidence of scours were observed with the aureomycin-supplemented calves. Digestion studies indicated that neither aureomycin nor Ethomid C/15 had any significant effect on the digestibility of feed nutrients. Aureomycin had no effect on the digestion of crude fiber. The digestion of all nutrients, with the exception of crude fiber, tended to be highest when the calves were 5 weeks old. This was probably due to the influence of milk fed during this period. Crude fiber digestion increased with advancing age of the calf. Blood studies indicated that neither aureomycin nor Ethomid C/15 had any effect on blood levels of urea nitrogen and that Ethomid C/15 had no effect on the blood levels of non-protein nitrogen. Aureomycin appeared to lower blood levels of non-protein nitrogen for the first 7 weeks. This depression corresponded very closely to the stimulation in growth that occurred during this period.