Animal Health & Welfare

It is important for pets, zoo animals and farm animals to stay healthy. Animal scientists study  how animal housing and feed can affect health. Animal scientists also address welfare concerns in animal production.

Animal Science Illustration

What are animals fed and why?

Digestion occurs differently in animals like cattle and sheep. These species are referred to as ruminants and digest their food through fermentation in a four-chambered stomach. Their stomach is filled with bacteria that help break down plants that humans can not eat. These bacteria also help produce nutrients for their host species.

“You chew your gum like a cow!”

Cattle have a reputation for having bad table manners and being very loud eaters! This is because they never completely chew their food. Instead this partially grinded food goes to the chambered referred to as the rumen and is stored as “cud”. The cud then becomes swallowed and passes to the next three chambers known as the reticulum, omasum, and abomasum.

Depending on their stage of life, ruminant animals need different amounts of energy. For example, dairy calves do not have a four chambered stomach until later in life. When a ruminant is producing weight or need to gain weight, they need more energy. This energy comes from a total mixed ration (TMR) containing multiple mixed feeds. For dairy cattle, this TMR consisted mainly of hay or corn silage, which is produced by grinding the whole plant at harvest and then fermenting the mixture in a silo. This allows the dairy cow to produce milk high in butterfat, making the milk more valuable. This is usually fed as the animal is being prepared for market. For the majority of their life, ruminants should be fed a diet consisting mainly of forage (like grass) and roughage (like hay). Farmers are always cautious to not feed too much grain and not enough forage and roughage as this can make a ruminant sick.

Non-ruminants, which are animals like chickens and pigs, digest their food more like people do. They are fed mixed rations of energy and protein from foods such as corn and soybean meal.

Alternative feeds

Feeding animals can be pricy and is many times the most expensive part of animal agriculture. In order to keep costs low, and their animals healthy, farmers feed by-products from other industries to reduce the amount of hay and grain. Products such as distiller’s grains and soybean hulls contain many valuable nutrients. This is also environmentally conscious as it prevents waste!

Feed additives

Animals don’t only need protein and energy, they also need vitamins and minerals. Farmers can buy vitamin and mineral mixes that can be supplemented into an animal’s daily ration. Vitamins and minerals can also be feed as a solid block that the animals will lick while out grazing.

Two very important minerals are calcium and phosphorous. These minerals are important for proper bone and teeth development, metabolism, and more. It is normally suggested that the ratio of calcium to phosphorous is about 2:1 for normal functions. One easy way to keep this balance is to feed dicalcium phosphate. Like other nutrients, the levels of these minerals also depends on the age of the animal.

Farmers will also add medication to animals’ rations in order to treat or prevent disease. Farmers carefully track and record when they feed medications as animals going to market must be taken off medications weeks in advance. This time, known as the “withdrawal period”, ensures that there is no medication in the meat or other products humans will consume.


Too much fat can cause health problems, but fat is not all bad. In fact, humans and animals need fat in their diets in order to stay healthy.

Fat is involved in several important body processes, including liver function and the creation of chemicals, called hormones, that send messages in the body. Fat also provides the most energy out of any of the nutrients.

Energy, in nutrition, is measured in units called kilocalories. In human nutrition, a kilocalorie is the same as a Calorie, spelled with a capital C. These are the units that show up on the “Nutrition Facts” on the side of your cereal box. Every gram of fat provides nine kilocalories. Every gram of carbohydrate or protein provides four kilocalories.

Fat in an animal’s diet can come from some of the food they already eat. It can also come from supplements, like fish oil, that the farmer can feed if that animal needs the extra energy.

Baby animals

Most baby animals are fed on milk from their mothers for the first weeks or months of their lives. One of the most essential nutrients for young mammals is colostrum. A mother’s mammary glands produce this colostrum for one or two days after birth. Colostrum contains numerous antibodies and growth factors that help the young develop a strong immune system. In calves, farmers monitor the colostrum through blood samples. This helps determine if there is enough Immunoglobulin G (IgG), a main antibody needed by calves.

When the animals are old enough and almost ready to stop feeding from their mother, farmers may choose to start creep feeding. Creep feeding involves putting hay or grain behind a special fence that allows only the baby animal access to the feed. As they grow, the baby animals may have to crouch down, or “creep” to get to the feeder, which is where the process gets its name.

Unlike other farm animals, baby chicks and other hatching species are not fed from their mother. When they first hatch, the yolk of their egg is absorbed into their intestines through a special opening, similar to a human navel. Once the chicks arrive at the farm, they are fed the same feed as the adult birds.

And what about horses?

Horses are unusual. They aren’t ruminants, but they’re not non-ruminants either. Instead, they are what are called hindgut fermenters.

Horses’ stomachs are a lot like non-ruminant stomachs. They secrete digestive liquids that help the horse to break down the food they eat. These kinds of stomachs are not good at breaking down fiber found in the stems of grass and hay.

But horses eat grass and hay. So why can they do that?

Horses can digest hay because they have an enlarged cecum, or appendix, that can hold about eight gallons of feed. The cecum acts like a ruminant animal’s stomach. It has bacteria and other microorganisms that help the horse to break down the fiber in its diet. In this way, horses can function like a ruminant animal.

Because of this, horses should be fed similar ruminants. The majority of their diet comes from forage or roughage and any extra energy comes from limited amounts of grain. But they do require a higher protein quality and better forage.

There are many feeding problems a farmer or owner must consider when feeding their horse. For example, horses should not exercise with an empty stomach because they risk developing ulcer. Just like other species, age and energy requirement is also important to recognize. When a young foal’s (horse under one year) diet is high grain they risk developing angular limb deformities. This means that their bones grow too quickly and therefore forms incorrectly. High grain diets can also lead to a disease known enterotoxemia. This is when there is a change in the bacteria in the hind gut, changing the pH level. This eventually leads to another disease known as laminitis, a painful inflammation of a bone in the foot.

Toxic Plants

Farmers have to be conscious of the plants in the grazing fields. Certain plants can be poisonous and lead to sickness or death. Some examples are Milkweed, Tall Fescue, and various Poppy plants.


Though it is often forgotten, water is perhaps the most important nutrient of all because it is needed for almost all processes that happen in the body. Humans and animals can survive weeks without food but only a few days without water. Therefore, it is important for the farmer to provide plenty of fresh, clean water at all times.

Jr Animal Scientist

A Jr. Animal Scientist membership is a great way for kids to learn about science and the animal world.

Through the Jr. Animal Scientist magazine and special online resources, kids can learn about pets, farm animals and zoo animals. Scientific information is tailored for kids ages 5 to 9 (K-3rd grades). Eye-catching photos and exciting animal activities add to the fun! Plus, all Jr. Animal Scientists get special prizes just for joining.

Join today