National Heartworm Awareness Month.

National Pet First Aid Awareness Month. This event is an effort by the American Red Cross to draw attention to the need to know specialized pet first aid.

Prevention of Cruelty to Animals Month. (ASCPA)

National Pet Month. (UK)

April 6: National Siamese Cat Day.

April 7: Every Day is Tag Day.

April 11: National Pet Day.

April 8-14: Animal Control Officer Appreciation Week. 2nd full week in April.

April 15-21: National Pet ID Week.

April 18: Pet Owners Independence Day.

April 22: Earth Day.

April 15-21: Animal Cruelty/Human Violence Awareness Week. An effort by the Humane Society of the United States. Third week in April.

Third week in April. National Pet ID Week.

April 28: World Veterinary Day. This event from the World Veterinary Association is always celebrated on the last Saturday in April.

April 27: Hairball Awareness Day. 

April 30: Adopt a Shelter Pet Day.

April 30: National Tabby Day.