As of 2021, the top 10 countries with the most number of cattle are:

1. Brazil: approximately 215 million head of cattle
2. India: approximately 205 million head of cattle
3. China: approximately 131 million head of cattle
4. United States: approximately 94 million head of cattle
5. Australia: approximately 29 million head of cattle
6. Russia: approximately 22 million head of cattle
7. Mexico: approximately 21 million head of cattle
8. Indonesia: approximately 20 million head of cattle
9. Argentina: approximately 17 million head of cattle
10. Canada: approximately 13 million head of cattle

It's important to note that the data on cattle numbers can fluctuate due to a number of factors such as changes in consumer demand, weather conditions, disease outbreaks and Government policies. These numbers are estimates and are also subject to change over time.