Fertilizer made from pigs and cows

From your query, we understand that ‘manure’ is being used as a fertilizer for the crops which will eventually be used to feed the cattle.

Firstly, we need to understand the nature of manure. Generally, manure is used as an organic fertilizer made from the dung of domestic livestock which includes horses, cows, pigs, and poultry. Usually, soil and other ingredients are also mixed with the manure to solidify it, and this is then mixed into the soil. This results in a complete metamorphosis occurring which makes it permissible to utilize. The dung of these animals no longer remains in its original form, nor do any traces of it remain. Rather, it all turns into soil when mixed with the soil. [[i]]. Hence, any crops grown using the said manure will be permissible to consume [[ii]]. In conclusion, it will be permissible to slaughter an animal that eats from these crops for Qurbani [[iii]]

[i] Manure – Wikipedia