Until 1855, the parish churches were the recorders if birth, marriages and death of their parishioners. The different religious denominations had their own responsibility to keep their own records, and many did not.
Kirk Session books and registers weren’t always kept once official registration began in 1855 and many have been lost or found their way into an individual’s home and may have been disposed of when he/she died.
The following link should take you to the transcribed burial registrations of the Loudoun Church, Newmilns, Ayrshire. It should be noted that it’s a burial register and not a death register although the burial would follow very soon after death. Many of the houses were small and often overcrowded so it was better that the burial should follow fairly soon after death.
The entries in the register maybe difficult to understand as spelling was not always the best and the transcriber may have found the hand writing difficult to read.