I'm doing this exact same thing so I can give some insight into how I get it done. I have one cyclic assembler making cakes for 16 culunary generators. Even at full speed, the CA doesnt quite keep up with the culinary generators fuel requirements. I may add an additional one or two.
Milk: I am using ranchers as suggested above. I have a 10x10 area for the cows (I dont like small pens for animals) allowing them to move around but still be near enough to the range of one of the three ranchers circling the pen (5x5 area in front of them IIRC). I dont have perfect coverage, but the milk production is more than what I use as full speed right now. I would say I had about 25-35 cows in the pen. Each cow has a cooldown time before the rancher can milk them again which is the reason why I have as many as I do.
You didnt ask but for others who might be attempting this as well here is what I have so far...
Eggs: On the top floor of my base there is a chicken coup with about 30-40 chickens. The eggs drop on the floor and get sucked up by vacuum hoppers.
Wheat: Basic wheat farm with a small twist. I have MFR handling the planting and havesting. The watering is done by a sprinkler sitting on a tesseract. The tesseract sends it water and bonemeal. There is no actual water source block so the sprinkler is the only thing hydrating the soil. Back at cow pen I have a sewer taking the animal waste and piping it over to the wheat farm to create fertilizer via the composter. The wheat then gets sent to a CA to convert it strait to wheat flour before storing by the cake maker.
Sugar: Basic harvester/sugar setup. I have overflow going to a set of coke ovens so I can get sugar charcoal and subsequently sugar coke. I need creosote for making rails as well so why not.
I plan to have a computercraft program to control the CA making the cakes so that when one of the ingredients runs low, the CA wont use it all up and subsequently have its inventory slots filled with other items until there is no more room for the one running low. As of now the CA will halt after 8ish hours of operation as the least highest production ingredient runs low and gets pushed out as a result of other items filling the slots in the CA. I could potentially use AE to manage this but AE costs more energy on my server to operate (x2-x4 default). I avoid using it for automating power production to keep efficiency higher. I could overproduce the ingredients but I dont like voiding items or having my buffers back up. Makes for a very unhappy server. If you are still reading this, gold star.