Cautery Sliver — ruling 1

Abilities that Slivers grant, as well as power/toughness boosts, are cumulative. However, for some abilities, like flying, having more than one instance of the ability doesn't provide any additional benefit.

Cautery Sliver — ruling 2

If the creature type of a Sliver changes so it's no longer a Sliver, it will no longer be affected by its own ability. Its ability will continue to affect other Sliver creatures.

Cautery Sliver — ruling 3

Note that the first ability can affect any kind of creature, but the second ability can affect only Slivers. Both abilities can affect players.

Cautery Sliver : règles, fonctionnement et interactions (MTG)

Cautery Sliver is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

All Slivers have ", Sacrifice this permanent: This permanent deals 1 damage to any target." All Slivers have ", Sacrifice this permanent: Prevent the next 1 damage that would be dealt to target player, planeswalker, or Sliver creature this turn."

How it works : Cautery Sliver

Original English text — Wizards of the Coast / Scryfall

#1July 1, 2013· Wizards of the Coast
Abilities that Slivers grant, as well as power/toughness boosts, are cumulative. However, for some abilities, like flying, having more than one instance of the ability doesn't provide any additional benefit.
No other card is named in this ruling.
#2July 1, 2013· Wizards of the Coast
If the creature type of a Sliver changes so it's no longer a Sliver, it will no longer be affected by its own ability. Its ability will continue to affect other Sliver creatures.
No other card is named in this ruling.
#3February 1, 2007· Wizards of the Coast
Note that the first ability can affect any kind of creature, but the second ability can affect only Slivers. Both abilities can affect players.
No other card is named in this ruling.