Effects of dietary energy, free choice alfalfa hay and mass medication on calves subjected to marketing and shipping stresses.

Five-hundred and fourteen calves subjected to the stresses of marketing and shipping from Florida to New Mexico were used to study performance after arrival at the feedlot. Flaked milo diets containing 50 and 75% concentrates promoted more rapid recovery of purchase weight and more efficient gains than a diet containing 25% concentrates. Free-choice alfalfa hay with the flaked milo diets reduced death loss, number of calves requiring medication and number of treatments per medicated calf. A 3-day mass medication with oxytetracycline injected intramuscularly at 11 mg/kg body weight reduced death loss and number of calves requiring subsequent medication. Calves requiring subsequent medication, however, needed more treatments than control calves. Dry matter and energy digestion determined with lambs increased with concentrate level but decreased with addition of alfalfa hay. New energy intake was highest for the 50% concentrate diet during the first week and for the 75% concentrate diet during the next 3 weeks of the 4-week receiving period.