The pet industry is one of the few to be essentially "recession-proof," and its overall growth makes it one of the most intriguing investment opportunities in the market. The American Pet Products Association estimates that $58.51 billion will be spent on pets in the United States in 2014, a 5% increase from 2013, and here's how this projected spending is broken down:

Category 2014 Estimates 2013 Actual
Food  $22.62 billion $21.57 billion
Vet Care $15.25 billion $14.37 billion
Supplies/OTC Medicine $13.72 billion $13.14 billion
Services: grooming/boarding/etc. $4.73 billion $4.41 billion
Live Animal Purchases $2.19 billion $2.23 billion
Total $58.51 billion $55.72 billion

With these statistics in mind, let's take a look at the five best investment options to profit from this growth and how they performed in their most recent quarter:

The pet product king
PetSmart (UNKNOWN:PETM.DL) is the largest specialty retailer of pet products and solutions in the United States, offering everything from pet foods and toys to grooming, training, and adoption services. The company also operates PetsHotels in 199 of its stores and has Banfield Pet Hospitals attached to approximately 60% of its locations. PetSmart is easily described as the one-stop shop for all things pets.

Cat and owner

Image source: Getty Images.

Fourth-quarter results for fiscal 2013 were released on March 5, with earnings per share growing 19.6% to $1.28 and revenue growing 2.9% to $1.80 billion on a 13-week comparative basis from the year-ago period. PetSmart also provided its outlook on fiscal 2014, calling for earnings growth of 10%-12.9% and revenue growth of 4%-6% from fiscal 2013. PetSmart is well-positioned to continue being the dominant pet product retailer, and its stock is trading over 11% below its 52-week high, representing a great buying opportunity for investors.

Saving pets and draining wallets
VCA Antech (NASDAQ:WOOF) is a leading provider of pet health care services, with over 600 veterinary hospitals in the United States and Canada. Anyone who has a pet knows vet bills are some of the highest expenses associated with ownership, and one injury could end up costing thousands of dollars; this is where VCA Antech shines to help pets live the longest and healthiest lives possible. The company also offers laboratory testing, diagnostic imaging equipment, and marketing solutions to the veterinary industry. 

Source: VCA Antech.

The company released its fourth-quarter report for fiscal 2013 on Feb. 13, and it contained record results; earnings per share came in at $0.28, and revenue was a record $435.5 million, representing year-over-year increases of 16.7% and 4.1%, respectively. VCA saw revenues increase 4% at its animal hospitals and 5% in its laboratory testing segment, and this was helped by the company's strategic acquisitions. For fiscal 2014, VCA expects diluted earnings per share to increase 5.2%-11.7% and revenue to increase 5.6%-6.9% from fiscal 2013, which would result in another great year.

VCA Antech is my favorite investment option in the pet industry today because of the strength of its business and the constant and growing demand for its services. Also, the company's stock trades more than 10% below its 52-week high, making for a perfect entry point.

Keeping the vets stocked up
MWI Veterinary Supply (UNKNOWN:MWIV.DL) is one of the largest distributors to veterinarians in the United States, supplying everything from gloves and cotton balls to x-ray machines and surgical devices. Animal hospitals, like VCA Antech's, are becoming as technologically advanced as human hospitals, and this has led MWI to become a billion-dollar company. 

Source: MWI Veterinary Supply.

On Feb. 6, MWI released first-quarter results for fiscal 2014, reporting earnings per share of $1.45 and revenue of $687.3 million; this represented growth of 9.9% and 19.9%, respectively, from the same period a year ago. The company also reaffirmed its outlook on fiscal 2014, calling for earnings growth of 10.5%-14.5% and revenue growth of 23%-25%. MWI Veterinary Supply and the pet health care industry have growth on their side, and MWI's stock sits nearly 20% below its 52-week high, resulting in an investment opportunity. 

Keeping your pets safe
One of the largest companies dedicated to ensuring the safety of your pets is Neogen (NASDAQ:NEOG). Neogen develops food safety products that test for bacteria, allergens, toxins, and drug residue among other things, which combat the rising problem of food-born illness. The company also manufactures animal health care products including pharmaceuticals, diagnostics, wound care, disinfectants, and veterinary instruments. Neogen's product offerings are distributed through numerous partners, including the aforementioned MWI Veterinary Supply, supplying thousands of veterinarians and animal hospitals throughout the world.

Source: Neogen.

On March 25, third-quarter results for fiscal 2014 were released; earnings per share were flat at $0.18, and revenues were up 21.4% to $62 million compared to the year-ago period. This was the 32nd consecutive quarter that Neogen reported a year-over-year revenue increase, and this quarter's growth was driven by a 32% increase in its animal safety product sales. The growth is expected to pick up in the fourth quarter, with analysts expecting earnings per share to increase 11%, and revenue to increase 17.9% from the prior year. Neogen trades more than 12% below its 52-week high today, but I think it will quickly regain strength because it is uniquely positioned in the industry and its product mix will keep its growth on an upward slope for several years.

The online medication superstore
PetMed Express (NASDAQ:PETS) is the parent company of 1-800-Petmeds, and it conducts its business entirely online and over the phone. The company is a licensed pharmacy, like CVS and Walgreens, and carries all major brands of medications that are FDA and EPA approved for animals; it also tests all of the products it carries to ensure they work and are safe for its customers. PetMed's online business model gives it much lower overhead and other costs associated with conducting its business, but it has also made it difficult to acquire new clients without heavy spending on advertising.

Source: 1-800-PetMeds.

On Jan. 21, PetMed Express released third-quarter results for fiscal 2014; earnings per share were flat at $0.23 and revenue increased 1% to $50.09 million compared to the same period a year ago. Online sales led the way during the quarter, increasing 2.1% to $39.5 million, and the company noted that the average order size increased by 1.4% to $72. Going forward, analysts do not expect much earnings or revenue growth, but the company does pay a hefty 5.2% dividend. PetMed Express is my least favorite of the five companies we have discussed, but it has fallen over 20% year to date and could outperform the others for the remainder of the year.

The Foolish bottom line
The pet industry has grown from a mere $17 billion in 1994 to an incredible $55.72 billion in 2013, and the growth is not expected to slow down anytime soon. PetSmart, VCA Antech, MWI Veterinary Supply, Neogen, and PetMed Express are five of the best investment options in the industry today and are differentiated enough to grow in harmony going forward. Take a look and decide which is your favorite way to play the industry and strongly consider initiating a position in the coming days.