It's possible, but six major things need to be fully understood in order for you to be able to, preferably legally, have a cow on your non-farm, non-agriculture-zoned land:
If you are in an agriculturally-zoned area, you will have far better luck bringing a cow on your property as a pet than you would if you were in a residential, suburban, or any other kind of zone, particularly within the jurisdiction of a town or city. You may run into the trouble where you are not allowed to have a cow on your property at all, and will have to find some other way to chase your dream of having a cow--preferably more than one--someday.
Feed & Water
Let's talk about feed and water. This are very, very important items to have for your cow. My BIG question is do you have enough money to feed a cow? Can you afford to feed a cow for the duration of its life? In order to see how much it costs to feed a cow, I need to first show you how much a cow will actually eat.
Let's compare a miniature cow to the biggest dog breed you can possibly find: the Great Dane. Why I'm doing this is to demonstrate that even the smallest bovine breed can eat a lot more than the largest dog you could have.
An adult Great Dane will consume between 4 to 6 pounds of food (usually doggy kibble) per day. For a 100 pound dog, that's approximately 5% of its body weight. Bovines consume an average of 2.5% of their bodyweight on a dry-matter basis, which is deceptive until we look at moisture content of what a cow eats. Moisture content of a feed for a cow can range from 10% to 80% moisture, depending on what that feed actually is. Thus, when moisture is included, a cow will consume around 3% to 12% of its body weight in feed or fodder on an as-you-feed-it (or just "as-fed") basis.
For example, a miniature cow that weighs around 500 pounds will consume around 12.5 to 15 pounds per day, on a dry-matter basis. However, when moisture is included, that little cow will actually eat 15 pounds to over 60 pounds of feed per day.
The key thing to know is that the better quality the feed is and/or the higher the moisture content, the more your cow will eat. She'll eat a whole lot more pasture grass (80% moisture) than she will dry hay (~10% moisture), for example. She'll eat more of the hay that has tested to be of great quality versus the hay that you found out to be poorer quality, even thought it looked and smelled fine to you.
Let's not forget waste. Cows are really good at wasting feed (particularly hay), and can waste between a quarter to almost half of their feed if you allow it. That's a quarter to half of your feed bill gone right there.
But that's not all. There's other things your cow needs to keep her healthy. That means minerals, vitamins, and possibly other supplements if the hay your feeding isn't good enough quality for her. Other supplements may include grain such as rolled oats or cracked corn, or byproducts like beet pulp, soybean meal, DDGs, brewer's grains, alfalfa pellets, or cottonseed meal. Different byproducts have different nutritional profiles so be sure you get the right ones according to what your cow needs.
All of this adds up. And this is regardless if this cow is simply a pet that is never to be bred or slaughtered for meat. If you intend to have a cow for 5 to 15 years, depending on how old it is when you bought it, that means you have to make sure you have the annual budget to keep your bovine healthy for the rest of his or her life. That may mean allocating at least $1,500 per year per cow (because cows are always better with another ruminant friend).
Then there's water. Do you have the means and source for good clean water for your cow? How much is it going to affect your monthly water bill that you (or even your parents) must pay? A single cow can drink around 10% of her body weight in water on average. In other words, that 500 pound mini cow will be drinking 50 pounds or 6 gallons of water per day. She'll drink more if it's a hot day, or if she's eating dry feed, which may mean she may drink almost 10 gallons a day! Water is a very important nutrient for a cow and can't be skimped out on, no matter how hard you try. Limiting access to water is like giving her almost the worst quality feed you can find. It'll make her sick and very unhappy.
While cows can do just fine with some trees as shelter, you may not feel so comfortable with that option, particularly if you don't have such big trees available--and if you're afraid that your cow[s]' frequent visits to those trees may damage them.
A lean-to shelter or a tiny barn or modified horse stable would be a good option to consider for your pet cow to keep her out of the bad weather, if she so chooses.
This is yet another important consideration that not many may consider in their quest for wanting to have a cow. What to do with all that manure?!
If you think the turd from a Great Dane is big, you'd be surprised at how big a cow turd can be. Cows will poop several times a day, leaving them in these big messy "pies" or "pats" that no cutesy doggy bag will be able to handle, and will definitely require the aid of a flat-bladed shovel and a wheel barrow.
What do you do with the manure? You could go out every day and clean up after your cow[s] and put it in a big manure pile, with a bit of straw, where it will decompose and eventually turn into compost. Or, you may be faced with other solutions like the landfill, or getting a rural friend to truck it away for a fee where they can use it on their land.
The big take-away here is that you can kiss your lawn good-bye if you decide to have a cow on it, unless you are keen to limit access to where you're feeding that cow in a certain area and leaving the lawn-turned-pasture to regrow until it's ready to graze. Manure, combined with trampling and wasted hay, will turn any nice grassy lot into a dirt pen. Beware!
In order to have a cow you need enough space for not only your cow[s], but also for the feed you need to store, and the manure pile I previously mentioned about. Do you have enough space?
One cow needs approximately 300 square feet of space to move around and to bed down in. This amount of space includes the feeding and mineral station she needs constant and ready access to.
To keep your cow in that space, it needs to be fenced. Fencing helps contain her and prevent your cow from wandering to places where she could get herself and others into a lot of trouble.
Then there's the part where you could have a cow to graze. On average, about one to two acres is enough to supply a cow for a month. Some areas may be less, some even more, depending on precipitation, irrigation, location, etc. One acre is equivalent to 43,560 square feet.
If you have two cows (which is better than one), then you need even more space than what I mentioned here; try double what I mentioned here.
Cows are social animals and need constant companions. Cows preferably like having one of their own kind as company, regardless if you're the one who's going to try to spend as much time as possible with your pet cow brushing it, feeding it, hanging out with it, etc.
Because it's way harder to have a house cow and because you're realistically not constantly living with your cow 24/7, that pet cow of yours is best with a companion, and I don't mean a cat or a dog either as it's less common for cows and dogs and cats to get along than you think. I mean another ruminant, like a sheep, or even another cow.
A horse or donkey? Big NO. Horses and donkeys can be really mean around the feeder, and will hoard as much feed to them as possible, and actively chase, kick, or bite your pet cow away. It's much worse for your cow if she's being outnumbered by equines.
With such a long answer for such a simple "yes or no" question, my answer to this is that it really depends. I've already stated that it IS possible to have a pet cow if you don't have a farm, IF you are able to meet all the requirements and responsibilities for keeping a cow. BUT if you're not ready for all these responsibilities and requirements, then the answer to that question is no, you cannot.
Ultimately, it all depends on you, and your context.
The Bovine Practicum Q&A "blog" is an informative, just-for-fun section where I find a variety of questions that are often (and not-so-often) asked by inquisitive people like you, and answer them to the best of my ability. Much of the questions have come from a wide variety of reaches from the Internet.
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