The hot blade cuts through this sensitive tissue impairing the hen's ability to eat, drink, wipe her beak, and preen normally. Rennet is derived from the stomach linings of calves. Rennet is used to make cheese. These substitutes can be either from vegetable sources, or may be created in a lab. Vegetable rennet is usually called 'rennin' to distinguish it from the animal-derived type.
Some soy cheeses contain cassein which is a milk-product.
Dairy cows are made pregnant yearly to ensure they produce adequate milk. In nature the calf would suckle for almost a year but nature, like the calf, is denied by the dairy industry. But as the inevitable by-products of relentless milk production each will have to endure one of several possible fates. Some females will be reared on milk substitutes to become dairy herd replacements and begin, at 18-24 months of age, the cycle of continual pregnancies. Some will be sold at market at 1-2 weeks of age for rearing as beef in fattening pens and slaughtered after 11 months, often without sight of pasture.