Cows with names produce more milk, scientists say - Telegraph

The average amount of milk produced by a cow over its annual 10-month lactation period is 7,500 liters. Those cows whose farmer's had names for them had an average higher milk yield of 258 liters.

https://www.telegraph.co.uk/news/earth/agriculture/farming/4358115/Cows-with-names-produce-more-milk-scientists-say.html