Many people are overly cautious about including alfalfa in a pasture. With proper management, an alfalfa based pasture will give you the best animal performance along with the highest yields of quality forage. Alfalfa's deep roots and heat tolerance make it the obvious choice for mid- to late-summer grazing. With a good rotational grazing system and best management practices, it will be very successful.
There are a number of grass species that should be considered. My preference is for orchard grass because of its early spring growth, rapid regrowth, and once the seed head is removed it stays vegetative for the rest of the growing season. Meadow brome is also an excellent pasture species. Timothy is often found in mixes but it has poor summer re-growth. Other grass species that warrant consideration include ryegrass (especially for a short duration pasture), reed canary grass, festolium (cross between ryegrass and fescue) and possibly bluegrass (especially for a long term pasture). There is a good description of forage species in the OMAFRA Publication 811, Field Crop Agronomy Guide at www.omafra.gov.on.ca/english/crops/pub811/3species.htm
Soil Fertility
Soil fertility is a major consideration. The new seeding will not perform very well if the pH is too low, or if the phosphorous and or potassium levels are low. Pasture fertilizer rates based on soil tests are also in the Agronomy Guide. www.omafra.gov.on.ca/english/crops/pub811/3fertility.htm
Seeding
Forages can be no-tilled or planted into a tilled seed bed. The seed bed should be firm enough to allow for good depth control and seed-to-soil contact. Forage seeds are very small and should be planted 7-10 mm (1/4 - ½ in) deep. The use of a companion crop is optional. If using a companion crop, consider using oats harvested as haylage or baleage at the boot to very early heading stage. This will eliminate the competition effect from the companion crop and allow the new seedling every opportunity to grow during July and August. The field should not be grazed until the forage plants are well rooted. Cattle tear the pasture plants off, and if they are not fully anchored in the soil they will be pulled out!
Planting the appropriate species into a reasonably fertile seed bed should give you a productive pasture for many years.
Source: OMAFRA