I guess it depends how you count them:
> Other key findings in the report were:
Of the 89.3 million head inventory, all cows and heifers that have calved totaled 38.3 million.
There are 28.9 million beef cows in the United States as of Jan. 1, 2023, down 4% from last year.
The number of milk cows in the United States increased to 9.40 million.
U.S. calf crop was estimated at 34.5 million head, down 2% from 2021.
All cattle on feed were at 14.2 million head, down 4% from 2022.
from
https://www.nass.usda.gov/Newsroom/2023/01-31-2023.phpSo the question is: did they estimate the young buffalo calves as well? That seems to be what brings the cow total number from 40 to 90 million.