Efecto de la sustitución de monensina sódica por aceites esenciales o levaduras sobre la performance de terneros destetados precozmente y alimentados a corral con dietas concentradas

The work was carried out between January 2 and March 12, 2021 in the pens of the Unidad de Producción intensiva de Carne, located at the Mario A. Cassinoni Experimental Station, located in the department of Paysandú, on Km. 363 of National Route No. 3. The objective was to evaluate the potential use of essential oils and yeasts as substitutes for monensin sodium, in feedlot diets for early weaned calves, evaluating performance, conversion efficiency, pH, consumption rates and patterns, respiratory frequencies and growth. Twenty-four Hereford calves born in the spring of 2020 from the EEMAC experimental herd, early weaned with an average age of 69 +/- 12 days and weaning weight of 80.1 +/- 10.1 kg, were used. The animals were randomly assigned to 24 individual pens with the following treatments: 1) Control: Ad libitum feeding of the RTM diet + 0.5 grams of a 20% monensin sodium source; 2) Essential oils: Ad libitum feeding of the RTM diet + 0.7 grams of an essential oil source; 3) Celmanax: Ad libitum feeding of the RTM diet + 1 gram of a yeast source. Each treatment consisted of 8 replicates (n=8 pens, 1 calf/pen), each animal constituting one experimental unit. In none of the variables analyzed were there significant differences between the control treatment and the alternative treatments. This could indicate that both essential oils and yeast (Celmanax) have the potential to replace monensin sodium as a nutritional additive in rations for early weaning.