Animal vaccination immunises domestic, livestock, and wild animals, with the practice pioneered by Louis Pasteur who created the first chicken cholera vaccine in 1879, followed by anthrax and rabies vaccines—while Edward Jenner's 1796 cowpox discovery led to the WHO's eradication of smallpox in 1980. This veterinary field is a major economic force, with the industry valued at $7 billion in 2017 and projected to reach $9 billion by 2024, and it is recognised as the most cost-effective method for controlling infectious diseases. The main challenges are access and availability, particularly for the 600 to 900 million poor farmers in developing countries whose livestock are essential for food and income. Availability is hindered by market dynamics, as producers focus on profitable markets, leaving diseases that affect poorer communities—like dog-transmitted rabies—neglected, while government-controlled vaccines can be too expensive for smallholder farmers. Additionally, animal vaccines face less stringent regulation compared to human vaccines, impacting their development and distribution.