Total digestibility of nutrients in Angus cattle fed a high-energy diet and different doses of narasin.

• Grant number: 23/09525-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2023
• End date: August 31, 2024
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Danilo Domingues Millen
• Grantee: João Victor de Paula Germano
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

The study aims to evaluate the effects of the inclusion of different doses of Narasin on the total digestibility of nutrients in Angus cattle fed a high-energy diet. It will be used 3 36-mo-old Angus steers of about 680 kg, cannulated in the rumen, in a 3x3 Latin square design, and replicated twice over time; then, the three animals will alternate between treatments according to the six experimental periods proposed. The treatments will be as follows: Treatment 1: 13 ppm of Narasin; Treatment 2: 20 ppm Narasin; and Treatment 3: 27 ppm Narasin. The duration of the study will be 156 days, where each period will last 21 days (the adaptation will be carried out in 14 days and the samples collections in 7 days), with washout intervals of 5 days between the periods, where the animals will be released in the pasture to induce the standardization of the ruminal microbiota and avoid interference from previous treatments. The total digestibility of nutrients will be observed during the experimental periods. Between days 10 and 19 of the experimental periods, 1g of TiO2 per kg of dry matter will be administered via cannula, 50% at 08:00 and the rest at 16:00. Between the 15th and 19th day of each period, samples of feces, diets, and leftovers will be collected, in which the dry matter, crude protein, NDF, starch, ash, and titanium contents will be determined for future calculations of digestibility in the total digestive tract.