Artificial insemenation: Conception rates won't be near as good as with natural service. It is quite difficult to know when the cow's in heat (especially if she's not with other bovines). You have a very small window during the time she is in heat to get her bred. With sexed semen you should buy two straws because it has been weakened while being sexed in the lab. With sexed semen you can expect 90% heifers and 10% bulls. AIing is not for the inexperienced. You would need to pay your vet or the semen rep to AI your cow.
Plus points to AI include: Being able to get top genetics at a good price. Not having to put up with a bull. Being able to purchase sexed semen. Not having to feed the bull. Using rare breeds if you like (such as Ayrshire).
If you decide to use Jersey semen, MAKE SURE that he sires good teat length. Most of the sires today sire daughters with tiny teats. With larger teats you get more of a squirt (milking won't take as long), and when the animal has just freshened tiny teats can sometimes be impossible to hand milk. Now a days they're breeding smaller teats into the dairy cows because they machine milk most of them anyway, and there's a lesser chance of injury with smaller teats.