Effect of roughage and physically effective neutral detergent fiber inclusion on ruminal short chain-fatty acids and ammonia concentrations in finishing cattle

• Grant number: 24/16234-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: January 01, 2025
• End date: December 31, 2025
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Murillo Ceola Stefano Pereira
• Grantee: Julia da Silva Ivo
• Host Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil
• Associated research grant: 21/09227-4 - Minimum physically effective Neutral Detergent Fiber (peNDF) requirement for feedlot cattle fed high-concentrate diets, AP.JP

Abstract

The objective of this study will be to evaluate the effect of roughage and physically effective neutral detergent fiber (peNDF) inclusion on ruminal short chain-fatty acids and ammonia concentrations in finishing cattle. Eight cannulated Nellore yearling steers (450 kg), will be housed in individual pens (21 m2). The study will be conducted as a 4 × 4 Latin squares balanced for carry-over effects with 2 × 2 factorial arrangement of treatments, with the following factors: forage inclusion (10% vs. 15% of dry matter of the diet) and peNDF inclusion (low [6.0%] vs. high [9.0%]). The peNDF will be switched by modifying the theoretical chop length of the corn silage, by 2.0 mm (low peNDF) or 9.0 mm (high peNDF). Each Latin square period will consist of 21 days including 14 days without sampling and 7 days of sampling, lasting 84 days. Samples of ruminal digesta will be collected through the cannula starting at 0700 hours on day 17 and every 12 h thereafter with a 3 h offset on subsequent days until day 21 (0700 h and 1900 h on day 17; 1000 and 2200 h on d 18; 1300 h on d 19; 0100 and 1600 h on day 20; and at 0400 h on day 21). Will be evaluated as variables: short chain-fatty acids production and ruminal ammonia concentration. All data will be analyzed using SAS PROC MIXED procedure, with Tukey test to compare means. The results will be considered significant at the 5% level of significance and trends will be considered when 0.05 < P < 0.10.