well jez what do you want spring calfing, autum calfing or just all year round
shed size a 60ft by 30ft should be aducate, if your a spring calfer you put the cow and calf out to a feild one day later so
you will need some were to keep 3/4 cows and calfs for a day, if your a autum you will either need to divide the cow house so you can put cows and calfs inside again until the spring or have another shed, and if you want to finish the calf for slaughter you will need another shed for store cattle (1 year old) and the finishing cattle (aprox 24 months old give or take) then you will need some were to handle and load cattle.
hope this helps a bit \ its alot of sheds