English to Portuguese Medical Livestock / Animal Husbandry

Why are the kibbles differing in size sometimes?
For producing the kibbles/croquettes we use die-plates, through which the product is pressed. After a certain time the die-plate is **washed out, which results in increase of the die-plate hole sizes and as well in bigger kibbles. As soon as the kibbles reached a maximum size of defined range, the diet-plate will be exchanged, which lead to kibbles with smaller size.

Contexto: Produção de um alimento para cães.

PT-PT, por favor! Obrigada!