Hi
Generaly in idempiere when you have to deal with product that can be add to storage or have quantity use material receipt to increase your qty and shipment for the opposit, and for loosing quantity ex cow death or wasted milk use physiqual inventory to balance the storage and explaine the lose.
Now for pricing create this same products with same names and configuration but this time as service and create sales order for invoicing your clients, purchase order for paying your vendors.
For cow that need unique ID in the farm use attribute instance for each cow that tou have in your farm.
Abdelaziz Kayoueche
Intégration des solutions ERP, développement web mobile et consulting.
N°36 Lotissement Kadri Ibrahim Ain El Bey - Constantine