Worth being clear upfront given the naming overlap in our range: this is the soft rubber teat that fits on our hand-feeding bottles, letting a newborn suckle milk or colostrum the way it naturally would from its mother. It's a different product entirely from the Goat Nipple in our drinking equipment line, which is a plumbed fitting for automatic water systems — this one is a hand-feeding accessory, used with a bottle rather than connected to any water line.
Because it's rubber and flexes constantly every time it's used, the nipple wears out faster than the bottle it's attached to — it can stretch, develop tears, or the flow hole can wear larger over time, all of which affect how well and how safely a newborn can feed from it. Keeping spares on hand and replacing it at the first sign of wear is standard practice, especially for anyone hand-rearing multiple newborns through a season.