The Iranian Animal Breeding Center (IABC) is currently milk recording and sampling three time per test-day(8 hours interval) approximately once every month. Milk samples are analyzed for fat and protein contents. There are some difficulties for having precise milk samples in some farms especially for three times sampling per day, and the costs of three times recording and sampling is also a problem. Estimation of lactation yield for milk, fat and protein yield is done based on test-day records and samples and the accuracy of there estimates depend on the precision of test day records especially milk sampling. The results of milk content are not satisfactory for farmer and specialist in the current milk recording system. Some researches have been done to reduce milk recording and sampling per test day (1, 2). In addition potential benefits of reducing milk recording and sampling are that more herds can be supervised and recorded per month. The objective of this research was to consider the possibility of reducing milk recording and sampling in herds with three times milking per test-day in industrial Holstein farms.