Effect of differing NDF levels in the solid diet on performance, metabolism and ruminal development of dairy calves

Abstract

The solid diet of calves is the main determining factor for ruminal development. As a result, these diets must contain ingredients with high digestibility, in addition to present adequate fiber level to maintain ruminal health. For the experiment, 45 Holstein animals housed in individual suspended cages will be used, and fed different solid diets: I- Conventional concentrate containing 16% NDF; II - Concentrate containing 25% NDF, replacing part of the corn with soybean hulls and III- Conventional concentrate containing 16% NDF plus ad libitum hay grass. All animals will receive 4 liters of milk replacer daily, divided into two meals. For the evaluation of the corporal development calves will be weekly weighted in a mechanical scale and corporal measurements such as withers height, hip width and heart girth, will be taken. Ingestive behavior will be assessed by two weekly observations. Blood samples will be collected weekly for analysis of metabolic indicators of ruminal development. At weeks 4, 6 and 8 of age samples of ruminal fluid, will be collected using an oro-esophageal probe, for pH, concentration of short fatty acids and ammonia-N determination. The data will be analyzed as repeated measures through the PROC MIXED of SAS (version 9.0, SAS Institute Inc., Cary, NC). (AU)