Cows are like that. They don't have much of an intellectual life, don't have jobs, and are attracted to live performances by musicians -- much like many teenagers.
However, it appears as though you may now have a part-time job as musical cow-herder -- if only you can convince the farmer to pay you. You should also convince him that your playing will result in more contented cows, and that this will lead to increased milk production and higher quality of milk. Point out that many milking barns (at least in the US) have sound systems that play for the cows while they are being milked.
Here is an authoritative reference (including references to research literature) that you can provide to the farmer in order to strengthen your argument: http://mentalfloss.com/uk/animals/26...isten-to-music.
Gary Merrill
Wessex EEb Bass tuba (DW 3XL or 2XL)
Mack Brass Compensating Euph (DE N106, Euph J, J9 euph)
Amati Oval Euph (DE 104, Euph J, J6 euph)
1924 Buescher 3-valve Eb tuba (with std US receiver), Kelly 25
Schiller American Heritage 7B clone bass trombone (DE LB K/K10/112/14 Lexan, Brass Ark MV50R)
1947 Olds "Standard" trombone (Olds #3)