I am Dr. K. Muraleedharan Nair from Kerala. I have been engaged in designing dairy farms for 2 cows to 5000 cows.
If you are going for a 30 cow dairy farm you will be having 30 young ones also within 2 years, provided the male calves are disposed at an early stage itself. If it is taken granted that the intercalving period is one year 5 cows out of the 30 will be dry at all time. If you are preferring for a tie stall the length of the shed will be 17.5 metres when you go for a shed on two line face to face system. The common feeding space(manger) will be given 2 metre width with a manger wall of 15 cm thickness. Manger wall will have 30 cm height from the feeding alley and 45 cm height from standing space of cows. Manger poles will be provided to a height of 45 cm from the top of manger wall to have safe feeding practice avoiding wastage of feed due to withdrawal of head during feeding.Standing space will be 180 cm long with cow seperators(preferably PVC filled with concrete to a height of 90 cms) at distance of 110 cms. Dung channel may be provided with a space of 60 cms at depth of 15 cms from standing space. Outer wall will have a height of only 30 cms to facilitate air circulation. If there are chances for invaders from outside, grills can be provided on the outer wall.
Please see the attachment for a model shed
If you want more informations in this regard please feel free to contact me oiver email drkmnair21@gmail.com.