Association of indigestible neutral detergent insoluble fiber and starch in the diet of dairy cows: Effects on digestion, performance and productive efficiency

• Grant number: 25/03322-6
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2025
• End date: July 31, 2027
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Francisco Palma Rennó
• Grantee: Francisco Palma Rennó
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Indigestible neutral detergent insoluble fiber (iNDF) is made up of the cellulose and hemicellulose fractions linked with lignin. The NDF content of the diet affects dry matter intake, nutrient digestion and the productive performance of lactating cows. Similarly, the concentration of starch in diets influences the intake and digestion of nutrients in a way that influences the productive performance of lactating cows. We recently evaluated the effect of including different levels of iNDF in the diets of dairy cows. The results obtained suggest that, unlike what happens in temperate countries such as the United States and Canada, corn silage in Brazil has a considerable increase in the concentration of NDF, which is 60 to 100% higher than in the countries mentioned above. Thus, in two previous experiments, the content of iNDF had a significant effect on the consumption and digestion of nutrients and the productive performance of lactating cows. However, although several studies have evaluated the interaction between the levels of starch and fiber in the diet of dairy cows, these studies were carried out with diets using corn silage and, invariably, other forages, with levels of NDF in the diets different from those usually used in Brazil. In this way, the recommendations for including starch in the diets of lactating cows from temperate countries, depending on the forages used, may not reflect the reality of what is usually used on farms in Brazil, especially in the southeast and central-west regions of the country. Thus, to date, the recommendations for including starch in the diet of lactating cows on diets based on corn silage with a high NDF content have not been reported in the literature. In this research project, 2 complementary experiments will be carried out in order to evaluate the effect of the association of NDF and starch content in the diet on the performance of lactating cows: 1) Effect of starch content in the diet of lactating cows fed corn silage with a high content of indigestible neutral detergent insoluble fiber (iNDF); and 2) Interaction of starch content and indigestible neutral detergent insoluble fiber (iNDF) in the diet of lactating cows. This project will determine the effects of starch content in diets based on high iNDF corn silage on aspects of digestion and performance in lactating dairy cows. From the results of this project, it will be possible to recommend starch levels in the diets of lactating cows based on high iNDF corn silage. The hypothesis of this project states that the higher starch content in high iNDF diets increases the intake and digestibility of nutrients, positively influencing the performance and productive efficiency of lactating cows. (AU)