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Impact of kernel processing and particle size in whole plant corn silage on the performance of dairy cows

Grant number: 16/16702-2
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): November 01, 2016
Effective date (End): February 28, 2019
Field of knowledge:Agronomical Sciences - Animal Husbandry
Principal Investigator:Luiz Gustavo Nussio
Grantee:Gustavo Gonçalves de Souza Salvati
Home Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The whole plant corn silage is characterized as a ingredient rich in energy, composed of a fibrous vegetative and starch fractions. The physical shape of the fiber has a great impact on the rumen and consequently on animal performance. The fine chopping forage is related to a reduction of salivation, rumen buffering and decrease in milk fat content. The particle size absence of silage also increases the incidence of disturbances such as acidosis, bloat, hoof problems and displaced abomasum. Because of their low physical effectiveness, diets such small particle size require more dietary inclusion of long fiber such as hay and haylage, increasing the cost of the diet. However in the manufacture of the silo, very large particles may decrease the capacity to transport the material to be ensiled and reduce the packing, resulting in loss of quality of forage and silo storage capacity. Furthermore, excessive increase in forage particle size increases diet sorting. Approximately 50% of whole plant corn silage energy value is derived from starch. The proper processing of the kernel fraction of whole plant corn silage positively affects the digestibility of starch and milk yield. Moreover, the digestibility of that starch is influenced by plant maturity at harvest, the type of forage harvester and the theoretical length of cut. In Brazil is often the use of pull type forage harvester without kernel processor. In this type of harvester, grain damage is usually obtained by reducing the length of cut. However, reduction of length of cut reduces the size of the fiber forage. Forage harvesters that damage the kernels without too reduce the size of the fiber, are desirable, especially when the aim is to formulate diets with high inclusion of corn silage without adding another source of long fiber. Based on the effect already described in kernel processing for hybrids with floury endosperm and the benefits of physically effective fiber the proposed project aims to evaluate: 1) the effect of the kernel processor in flint emndosperm corn hybrids in the performance of dairy cows and starch digestibility, 2) the physical effectiveness of fiber and performance of dairy cows on diets with increasing particle size and 3) identify the theoretical length of cut which provides adequate physical effectiveness of the fiber without affecting diet sorting by the animal.