blank if the column is empty

I have a userform to filter the multiple criteria insteadnof filtering . In another spreadsheet , it needs to set target for particular group. But however when I filter the second time , empty blanks will apppear as empty . Let just say in first selection , 10000 rows appear in column 6 .but when I select again of different option, and 400 data appear , for rows 401-10000 will appear as false. Thanks in advanced .

Sub Macro1() 
Dim Row As Integer 
Dim Blank As Integer 

Row = 2 
Blank = 0 

With Sheet4 
   Do While Blank <= 5 
      If .Cells(Row, 5).Value = "CAT" Then 
         .Cells(Row, 6).Value = "9" 
         Row = Row + 1 
      ElseIf .Cells(Row, 5).Value = "DOG" Then 
         .Cells(Row, 6).Value = "35" 
         Row = Row + 1 
      ElseIf .Cells(Row, 5).Value = "RABBIT" Then 
         .Cells(Row, 6).Value = "50" 
         Row = Row + 1 
      ElseIf .Cells(Row, 5).Value = "OTTER" Then 
         .Cells(Row, 6).Value = "6" 
         Row = Row + 1 
      Else 
         .Cells(Row, 6).Value = "2" 
         Row = Row + 1 
   End If 
'--- For detect end of row 
   If .Cells(Row, 5).Value = "" Then 
      Blank = 6 
   Else 
'--- Reset 
      Blank = 0 
   End If 
Loop 
End With 

End Sub