Rumen health of feedlot Nellore cattle receiving different combinations of sodium monensin and virginiamycin

• Grant number: 15/24613-7
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): February 01, 2016
• Effective date (End): January 31, 2017
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal researcher: Danilo Domingues Millen
• Grantee: Mylena de Mattos Ferreira
• Home Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil

Abstract

The objective of this study will be to evaluate the effect of the combined use of monensin (MON) and virginiamycin (VM) in the adaptation and finish period on rumen health of Nellore cattle macroscopically and microscopically. Seventy two 22-mo-old yearling Nellore bulls (370 kg) , backgrounded on pasture will be randomly allocated and kept in 24 pens (5,4 m² and e 0,8 m bunk per animal) according to the treatments:1) MON (30 mg / kg) in the adaptation and finish period, 2) MON (30 mg / kg ) + VM ( 25 mg / kg) in adaptation and only VM (25 mg / kg) in finish, 3 ) MON (30 mg / kg) + MV (25 mg / kg) in adaptation and VM (25 mg / kg) + MON (30 mg / kg ) in finish , 4 ) MV (25 mg / kg) in adaptation MON (30 mg / kg) + VM (25 mg / kg) in finish , thus characterizing a completely randomized design. Each treatment will be composed by 6 replications (pens) in this study. At harvest, one 1-cm2 fragment of each rumen will be collected from cranial and ventral sac for morphometric analysis such as number of papillae per cm2, papillae area and absorptive surface area and for histological assessment such as papillae surface area, papillae height, papillae width, keratinized layer thickness, and mitotic index.