The age of of your steer at purchase will determine how long you need to keep it and what kind of care it will need from you. If you get a "bottle calf" this means it isn't yet weaned and you'll need to feed it milk-replacer (purchase from the feed store) from a bottle until it's old enough to be weaned. Weaning happens about 4 months, but this depends on where you get it from and on the condition of the calf when it's 4 months old. When you're purchasing, be sure to check if it's weaned or not. Most ads will specify something like "weaned" or "eating all hay" if it doesn't, just ask!
You will need to get your steer some vaccinations annually. Most of the time, if you're purchasing from a reputable source, the calf will have received it's first set of vaccinations. If you purchase your steer old enough, you may not even be keeping it for a year and won't have to worry about doing any vaccinations. If you do need to get some vaccinations, you'll want to schedule this with a vet or do it yourself (ONLY do it yourself if you know what you're doing or have help that does!) very soon after bringing it home if it hasn't been done, or once a year if you're keeping it for that long. Vaccinations keep your steer healthy and help it gain weight and condition. Most calf vaccinations are pretty standard (BRSV, BVD, IBR, Lepto 5, Pi3) but double check with your veterinarian on what vaccinations they recommend for your area and how often. Sometimes an ad will say something like "been given 8-way" or "received 5-way vax." Those are just different combination vaccines, I always check where they got it and what exactly was in it.
You'll also need to deworm your steer. Typically this is done in the Spring after everything has thawed out and in the Fall after everything is frozen. You can get dewormers that are a pour-on liquid, a feed, or an injection. Feeds are easiest if you have a way to make sure the steer eats what you put out for it. There will be various dewormers that target various parasites, I usually like to go with the most comprehensive or common one first, and then rotate from there. However, contact your veterinarian for recommendations on deworming schedule and method of delivery.
You probably won't be keeping your steer long enough to worry about trimming it's hooves. I do recommend checking hooves and legs on a regular basis and making sure your steer is walking well (no limping or lameness) and that the hooves look healthy - no cracks, oozing wounds, etc. If you do see a problem, the course of action can vary. Generally if any of my animals appear lame, I like to identify the leg and do a thorough palpation and visual exam myself.
Please note, I am very familiar with working with livestock and know my way around the backside of a steer. I also work with my steers a lot so they are used to me being around and picking up their feet - this does get harder as they get older but since I don't own a chute, it's super important that they can tolerate me while I health check them. Please do not attempt to do this with your own steer unless you know what you are doing or have someone helping you that does!
If there is an obvious problem I can't fix, I call my veterinarian. If there isn't an obvious problem, I keep a close eye on them for about 3 days and watch for improvement or worsening conditions. Because we usually get playful dairy breed steers and we have a rocky pasture, it's not uncommon for them to be playing around and get a hoof bruise or two. These heal up fine by themselves, with rest. If you have concerns, NEVER hesitate to call your veterinarian! Often they can give you advice right over the phone.
Balls and Horns
Your steer may or may not be castrated when you get it. You need to know if your steer has been castrated when you get it - you DO NOT want to accidentally be raising a bull. That would be a disaster. Just as ads will generally specify if the steer is weaned, they will also specify if it has been castrated or say something like, "will band by request" (banding is just a form of castration) or "castration for additional cost." There are a couple different methods for castration and pros and cons to both. If you are going to take this on, banding will be easiest and I recommend contacting a vet the first time around if you don't want to band. I generally just like to purchase my steers already done and healed up - less chance for me to have to deal with potential problems.
Your steer may also have horns. Some breeds are polled, or naturally hornless, but some will need to be manually de-horned or dis-budded. We did not de-horn our first steer and I regretted it every time he would head-butt me. And they will, I promise. And it will hurt, I promise. And it will become increasingly dangerous for you and any other animals you keep with them, I promise. So these days I recommend getting a calf that is de-horned or a polled breed. Generally the younger the calf, the easier it is on them so take this into consideration when purchasing. This is something you can do yourself, but you do need some specific equipment so finding a friend to show you how it's done or asking the vet about it may be a good option the first time around.
Growing and Finishing
There are two stages to raising a steer for meat: growing and finishing. Growing means that the steer is, well, just growing. They won't bulk up at all during this time because their bodies are still growing and developing. The amount of time this takes will always depend on the breed. Beef breeds are generally smaller so the growing stage is shorter. Beef breeds are also bred to grow really well and finish quickly. Dairy breeds can vary. I stay away from Holsteins just because they are always big and have big bones. More weight from size and bones means less weight from meat. However, there isn't a right or a wrong. This all depends on your preference and how long you want to keep your steer around. The larger you let it get, the more meat you will have. We kept our steer until he was about a year old. We definitely will keep the next one longer, probably until he is between 18 months and 2 years. Ours was tasty, but everything was really small. Also keep in mind that if you keep your steer for an overly long period of time, the meat will begin to toughen.
Finishing is the stage after they are done growing. In this stage, they start to pack on weight and fat which will increase the flavor. I wrote this post on body condition scoring that may help you determine when your steer is finished. You'll want your finished steer to be between a 7 and 8. If they are super fat (9), you will just end up with a lot of fat around the outside of your cuts of meat and that is yucky. Usually you finish a steer with a higher fat feed, I like to supplement hay or pasture with a finishing grain mix. It will have a recommended feed amount, but I don't usually feed quite as much. The more grain you feed, the more marbling (flecks of fat within the cut of meat) and flavor the steer will have. If you finish only on hay and pasture, you may not like the flavor if you are used to meat from the store. I personally don't appreciate a particularly "grassy" flavor, which is why I do a mix of both. I'll eat a salad if I want to taste a plant. Also keep in mind that if you finish on grass and pasture it will take longer. And if your pasture is weeds and you finish your steer on those, it will also have an off flavor. Not to mention it probably won't finish well.
Slaughter and Processing
Your steer is finished, and you're ready to stock your freezer. Now what? There are a few different options for slaughter and processing. Processing is the actual dividing the carcass into cuts of meat and packaging them. If you take your steer to a processing facility, they will do everything for you. (I recommend this if you are going to sell any of your meat, it will need to be USDA inspected and if it is a reputable facility, no matter how small, they will have inspectors there.) Essentially you drop the steer off live, outline the cuts of meat you want and then pick up the packages. This is my preferred method. We do get our steers with the intent of raising them for meat, but we also love and appreciate them and I'm not sure I could watch the process. I have zero interest in doing it myself.
With that being said, I have been taken through a large, USDA inspected processing facility and watched everything from start to finish. I know what is happening and how it will work. I appreciate the time, effort and money the US beef industry has put into making it as humane as possible. The cattle were not scared. The yards filled with waiting cattle were clean, peaceful and quiet. The workers were respectful, careful and thorough. My hat goes off to those who work there and the service they provide to our country.
You can also hire a company or individual to come slaughter and process at your place. This would be convenient if you didn't have a facility nearby where you live. Keep in mind you will need a way to deal with everything that comes with slaughtering an animal (blood, unused parts, etc). This can be an inspected process, but you'd need to make sure if you were selling the meat.
Or you could do it yourself. There are many individuals who prefer this because they feel like it's their duty after raising the steer. If this is something you are interested in, I recommend hiring someone to come out to your place and do it so they can teach you and then having them there when you do it for the first time. It is essential you do it correctly to avoid any unnecessary pain and suffering. And also, it's harder than you think to get all the cuts of meat right! I've divided up a half carcass with a butcher and it was really fun! But it's definitely an art form and something that takes lots of practice.
Hopefully that gives you some direction for buying your first steer! If you're still not sure your ready, check out this post for a list of things to consider when raising your own meat.