The study was designed to test the effect of reducing dry period length on complete blood count and differential white blood cell count in early lactating cows. Cows were randomly assigned in 1 of 2 treatments: 1) traditional 60 d dry period (n=14) and 2) a shortened 35 d dry period (n=15). Holstein cows were blocked in pairs based on their previous 305 d milk, parity and expected calving dates. All cows were fed by routine ration of farm (total mixed diet). Using vacutainer tubes, blood samples were collected weekly from -7 to 50 day relative to calving via venipuncture of coccygeal vessels before the morning feeding to monitor complete blood count (CBC). The blood samples were kept in room temperature until analyzing for CBC by a hematology analyzer. The data were analyzed using the Mixed procedure of SAS for a completely randomized design with repeated measures. The white blood cells (P=0.64; 12277 ± 1798 and 13468 ± 1733 /μl, respectively), red blood cells (P=0.58; 5283037 ± 104596 and 5363237 ± 100280 /μl, respectively), platelet (P=0.13; 250271 ± 16913 and 286354 ± 16122 /μl, respectively), hemoglobin (P=0.91; 8.09± 0.15 and 8.11± 0.14 g/ dl, respectively), hematocrit (P=0.70; 27.97 ± 0.5 and 28.24 ± 0.5%, respectively), and also number of neutrophils (P=0.52; 3445.3 ± 198 and 3622.6 ± 188, respectively), lymphocytes (P=0.59; 7703.9 ± 1609 and 8920.2 ± 1547, respectively), monocytes (P=0.82; 685.6 ± 100 and 716.5 ± 96.4, respectively) and eosinophils (P=0.52; 173.8 ± 23 and 152.8 ± 22, respectively) were all similar among the groups. Red blood cell, hemoglobin and hematocrit were decreased and platelet were increased over the time (P<0.05). Result of this study showed that the reduced dry period length had no effect on cell blood count and differential white blood cell count

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