Im going to keep this as simple as I can. For more detailed information please do your own research. My goal here is purely for the understanding of why I feed my goats as I do as well as some good basic information for those new to goats that arent sure what to feed them. I want to help you understand why I am suggesting what I am vs just telling you to do so because I do.
Goats are ruminants. What does this mean? It means that they require grazing and browsing of plant based food to get their nutrients by fermenting it in their stomachs prior to its digestion. This means that the bulk of a goats diet must be made up of high quality hay and forage. Generally the stemmier the hay the less nutritional value to goats. Alfalfa is very high in protein compared to other hays, a calcium to phosphorous ratio of at least 2:1 is desirable for goats. The imbalance of this is what leads to urinary calculi in bucks/wethers. When combining alfalfa with other grass hays and some appropriate grain you can achieve the proper balance of nutrients and roughage making for the ideal diet for goats. Too much grain and not enough hay can cause other issues like pregnancy toxemia, acidosis, digestive problems and laminitis/founder. Sweet feed should not be fed exclusively to goats.
Goats are more like deer than they are cattle, though there are several similarities. The biggest difference is that cattle take 2-3 days to digest their food and goats have a very fast (1/2 a day) rumen passage rate. The goats overall diet should be 16% protein with forage/browser being its foundation. Rumens are in general slightly acidic and "sack feeds" tend to only raise this acidity because of the sugars, starches and other rapidly digested grains. By making the foundation of their diet hay/forage it helps to buffer the acidity with saliva and cud that has to be re-chewed and therefore remains in the rumen longer. A healthy and happy rumen makes for a healthy and happy goat.
For this reason I feed on a regular basis a minimum of 2 types of hay. I feed a high quality coastal bermuda grass hay free choice, as well as a chopped mixed hay. If I need extra weight/calories or have lactating does Ill add in another alfalfa or mixed hay as well. I feed dairy goat feed once a day or twice a day to lactating and growing goats, enough that they finish in about 15 minutes or so. Growing and newly weaned kids will have access to feed free choice. I always have quality minerals available free choice as well. Lactating animals will also receive extra protein to help with milk production.
PLEASE NOTE: If you get a goat from me this is how they will be eating. Any sudden changes can cause upset in their digestion and cause things such as bloat. Please make any changes slowly.