Begin the lesson by asking students the following question: How do you choose the right product for your pet from such a wide selection? Gather as many different print ads (newspapers, magazines, promotional advertising) for pet food as possible. Collect a variety of sample packages of pet food from your local pet superstore. Ask students: Which product is better for your pet? What would you want to know if you went to a place where scientists design the foods? Show the video to the class.

They're cute, most of them are smart, and they make great friends. No, not the kids in your class. Pets! An estimated 36 million homes in the United States have at least one canine. About 31.4 million U.S. homes have at least one feline. That's a lot of hungry pets to feed. And many pets (except for those finicky kitties) will eat pretty much anything we put in front of them. So how do the pet food companies determine what goes into their products to make sure your pet can and will eat it?

There are three basic ways to provide food for your pet: improvise food at home from table scraps, prepare pet food from regular food, or purchase commercial pet food. But different pets have different dietary needs-their food must provide the same nutrients found in foods their wild ancestors ate. Commercial pet foods deliver the nutrients and are convenient.

From a scientific perspective, pet food must contain the correct balance of ingredients for the pet's breed, age, size, physical condition, and lifestyle. It must be digestible to ensure that all the nutrition from the food is absorbed by the body rather than passed out as waste. Last but not least, it must be appealing and palatable enough to entice the pet to eat it.

To devise the perfect pet food, a great deal of scientific research takes place at facilities such as the Waltham Centre for Pet Nutrition (WCPN) in England. Over a thousand scientists in the Waltham network around the world conduct pet-friendly research in the areas of feeding behavior, dietary management, palatability, raw materials, product performances, and owner/animal expectations. The WCPN-home to 250 dogs, 450 cats, and 400 birds-generates more than 15,000 pieces of research daily. Many findings are shared with veterinarians and animal nutritionists worldwide.

In the United States, minimum standards for animals' nutritional requirements are established by the National Research Council, a federal agency. Based on research from organizations like the WCPN, the agency mandates, for example, that dog food include a balance of carbohydrates, fats, proteins, minerals, and vitamins. Even after 5,000 years as domestic pets, cats are still carnivores, so cat food must contain certain amounts of amino acids, taurine, arachidonic acids from animal fats, arginine, vitamin A, and niacin.

Next time you shop for food for Fluffy or Fido, compare the contents listed on the labels, and think about the research that went into putting together your pet's perfect meal. Bon appétit!

1. Many product labels now carry a statement indicating whether they use animals to test the product. Do you think animal testing is appropriate? Why? How could animals be protected against improper testing?

2. Pet ownership is a big responsibility. What are the advantages of owning a pet? Challenges?

Try being a product analyst, pet nutritionist, and package designer. Create a data log to compare the content analysis for several brands of dog or cat food. Include columns for serving size, target age, crude protein, etc. Examine the products themselves and record and compare your observations. Decide which one is actually best for your pet and which one your pet will most likely eat.

Materials

• variety of pet foods (at least three different types per group) of foodfor the pet chosen
• paper plates
• plastic forks, knives, spoons
• paper, cardboard, rulers, tape, glue, markers
• pens, pencils

1. Create work groups and select which kind of pet will be the focus of your product research and development.

2. Create a data log to compare the content analysis for several brands of dog and cat food. Include columns for price per gram/ounce, serving size,target age, crude protein, crude fat, crude fiber, moisture, calcium, phosphorus, main (first five) ingredients, as well as texture, smell, and appearance.

3. Record the data printed on the packages.

4. Open the packages and examine the products.

5. What differences and similarities do you observe? Compare volume and weight. Are the contents moist or dry? Do they seem greasy? What do they smell like?

6. Each work group should choose the food they think is the healthiest. Does it cost more than the others?

7. Relate the observations to what students in the class actually serve their pets.

8. Invite a veterinarian to comment on the work groups' choices.

Questions

If you owned a pet food company, how much would you budget for scientific research and development of new products? Raw materials? Would you use "only the best?" How much would go into marketing research and container costs? Explain your budget choices.

Test your cat or dog (or a friend's pet) to determine whether it is overweight. Stand above the animal to find its waist. If it is overweight, you won't see the waist behind its ribs. Next, use your hands to try to feel the pet's ribs. If you can see the ribs, the pet is underweight. If you can't feel the ribs, it's overweight. Check with a vet to confirm your observations.

All pets need plenty of fresh water. A dog, for example, who weighs about 30 kg and eats moist dog food needs about four cups of water a day. The same dog would need eight cups if he eats dry food. Select a breed of dog and calculate how much water it would drink. Next figure out how much you would spend on food for this dog for one year. Hint: Check package labels and pet care books to get the basic information for your calculations.