A newborn fawn is the size of two Chihuahuas. It's important to add seven drops of lactate as well to the formula. If you have a young fawn, do not add anything solid. When they are the size of the deer in the photos below, add some solid food to the formula such as baby rice or baby cereal. Mix it well with water until it has a pudding-like consistency. Deer love sweet tastes, and bananas are always a good source of sweetness.
Leptin acts as a hormone that modulates the size of the adipose tissues in the body. It regulates food intake and body weight. Leptin also acts on specific receptors in the hypothalamus to inhibit appetite through both counteractive and stimulatory mechanisms:y contrast, when fat mass increases, so do leptin levels and appetite is suppressed until weight loss occurs. In this way leptin regulates energy intake and fat stores so that weight is maintained within a relatively narrow range. Leptin also plays an important role in regulating and modulating the onset of puberty.
Put simply: long-term, leptin signals that the body has adequate adipose tissue (energy) stores; short-term, leptin signals that the body has had enough to eat. Both are supposed to result in the reduction in appetite.