Session 12:

Avian and Snake

Nutrition

Feeding Pet Birds

Types of Birds

Psittacine Breeds Passerine Breeds

Natural seed eatersSeasonal migratory birds

ParakeetsBudgiesCockatooMacawParrotsLovebirds

CanariesWrensSwallowsWarblersBlackbirdsCrows

Digestive Physiology of Birds

Differences in beak shape and size reflect adaptations to dietary sources of food

Stomach divided into distinct sections to compensate for lack of teeth and smaller amounts of saliva

Crop – used for wetting food and temporary storage

Mouth

Crop

Gizzard

Intestine

Ceca

Cloaca

Cloacal aperture

Esophagus

Digestive Physiology of Birds

Proventriculus

Digestive Physiology of Birds

Proventriculus (aka “true stomach”) – where gastric acids and enzymes begin chemical digestion

Gizzard (aka “ventriculus”) – strong muscular organ used to grind feed into smaller particles

Mouth

Crop

Proventriculus

Gizzard

Intestine

Ceca

Cloaca

Cloacal aperture

Esophagus

Intestine & Ceca – sites of nutrient absorption. Cecum is very small (or non-existent in some) so high fiber diets are out!

Cloaca – where urinary and digestive tract reunite. Urinary and fecal matter are mixed & excreted together

Mouth

Crop

Proventriculus

Gizzard

Intestine

Ceca

Cloaca

Cloacal aperture

Esophagus

Digestive Physiology of Birds

Digestive Transit Time

Definition: Time from the ingestion of food to the time when the undigested food is excreted.

Birds must have a constant supply of food. Some birds can be in a state of starvation within three days!Digestive Transit Times by

Species

Dairy Cattle: 24-72 hoursHumans: 18-24 hoursDogs and Cats: 12-18 hoursCaged Birds: <12 hoursBudgies & Finches: 3-6 hours

Of Special Note in Avian DigestionFaster metabolism

Must have “animal” vitamin D3, cholcalciferol

Require Proline and Glysine

Need increased amounts of sulfur amino acids

Extremely low urine volume; concentrated urine

Most do not utilize fiber

Avian Nutrition

Feed them based on their digestive tract ExampleOwls- Can’t drink based on the shape of their

beak- Can’t handle glucoseLorikeets- can’t handle protein

Faunivores

Carnivores and Piscivores- Adaptated to eating high protein diet

with a certain amount of fat - Cold water fish contain about 30% fat- Carnivores don’t utilize all of the prey,

they eat the mouse, digest as much as possible and then regurgitate the bones and hair ( owl pellets)

Insectivores

Can’t digest the entire insect- Some utilize the exoskeleton and some

penetrate the exoskeleton and digest the inside of the insect only

- When they eat the entire insect, they get all nutrients except Ca, which must be supplemented

- High protein requirement 50-75%- Insects high in protein and fat, low in Ca

Composition of Insects

Depends on species and stage of life cycle

Adult insects high in protein ( 50-75%) and lipid ( 5-35%) with low level of carbohydrates

Good source of vitamins, trace minerals and phosphorus, low in Calcium

Chitinous exoskeleton has a negative effect on digestibility

Florivores, Omnivores, HerbivoresFlorivores- nectovores, frugivores, garnivoresOmnivores- Most of our pet birdsHerbivores- Ratites- Combination of enzymes and microbes- Can be fore gut or hind gut fermenters

Precocial vs altricial birds

Precocial- Eat on own when hatched- Chickens, geese, ducks- Large yolk in egg with lots of nutients• Altricial- pigeon- crop milk- Hatchling dependent on parent for food- Eagles, owls, most of our pet birds

Seeding of the GI tract with microbes in young chicks Precocial chicks ingest the feces of

adult birds and feeds Altricial receive the bacteria when fed

by the adult ( regurgitated feed) “Cloacal drinking” vent “sucks” bacteria

in from the environment Retrograde urine, especially in ratites

Precocial chicks

Neonates have down, actively forage for their own food

Their digestive tract is immature when they hatch and takes up to 3 weeks to mature

Altricial chicks

Usually naked and helpless Parents must bring food to the chick and

actively feed it Digestive tract is well developed at hatch Milk production ( pigeons fed crop milk

for 2 weeks)- Crop milk nutritionally balanced, protein

and fat- Prolactin stimulates crop milk production

Nutritional Problems

Obesity- many pet birds and birds confined in zoos and sanctuaries

Leg abnormalities- confinement, improper diet, high

growth rates, vitamin D, Ca, P, Mn, Zn, niacin or biotin deficiencies

• Pendulous crop - Due to yeast overgrowth

Avian Feeding Management Birds tend to pick out certain seeds in mixes;

therefore don’t eat balanced diet

Should leave entire amount of food there until bird has eaten it all

Grass seeds (corn, oats, barley, etc) are too low in calcium; Sunflower, safflower seeds are too high in fat.

Best to feed a complete commercial feeding mix or pellets

Essential Nutrients & Ingredients in Avian DietsGrit:

made from ground minerals and sand; key in helping bird grind up foodstuffs; stays in the gizzard

Who needs grit?Birds that ingest whole seeds – helps with shellsBirds that remove seeds don’t really need grit

How to feed grit: 1/8 to ½ teaspoon every 2 years. Over

ingestion of grit causes intestinal impaction

Vitamin A: Promotes skin and mucous membrane health Feed high Vit A foods: carrot tops, broccoli,

sweet potatoes

Vitamin D (Cholcalciferol) Important in bone development Feed high calcium foods – almonds, cereals,

cheese, yogurt, oyster shells

Essential Nutrients & Ingredients in Avian Diets

What Budgies Eat

Prone to renal disease if fed 100% pelleted diet long term

Feed percentage of pellets, millet, sprouted seeds

Safe “human” foods: cooked pasta, brown rice, legumes, veggies, fruit, bread

Source: Oklahoma State University

What Cockatiels Eat Pellets Cereal & grain sources:

Cheerios, Chex, Total Dry or cooked pasta, corn, oatmeal Popcorn, crackers

Meaty, dark green, orange & yellow veggies

High Vit A content: beets, broccoli, carrots. NO lettuce, green peppers, zucchini, spinach!

Protein sources: legumes, tofu, small pieces of cooked lean meat

What Macaws Eat(Blue & Gold)

½ cup pellets with ½ cup fresh fruits and veggies (wash well!)

Seeds can be offered as treats (sunflower)

Protein sources: cooked sweet potato, yogurt

Fresh water at all times

What Parrots Eat

Commercial pellets for 60-80% of diet; Seeds less than 12% of diet

Table food: Mostly leafy green veggies, tomato, beets, peas,

carrots Unsweetened cereal; bread Small amounts of protein: cooked eggs, boiled

chicken, well done chicken bones

Limit seeds; leave shells on for parrot’s activity

What Canaries Eat

“Black and White” seed mix: 70% canary seed & 30% seeds from the rape seed plant; can use canary pellets

Very delicate, will dehydrate in short time; fresh water always!

Mineral grit and cuttlebone should be added

Sunflower seeds as a treat. Soak them overnight to help bird break them down

Source: University of Maryland

Chickens- layers that produce eggs, primarily Leghorn Starter feed- nutritional deficiencies and

imbalances may impair growth and future egg laying, contain antibiotics and coccidiostats

Grower- 6 weeks to sexual maturity approximately 21 weeks

Developer- can be inserted between grower and layer diet to increase production

Layer diet is fed free choice with large amounts of calcium for egg shell

Phase Feeding for Laying ChickensLayer phase 1-Birds are still growing and increasing in production, feed formulation is at maximum density-Onset of egg production until past the time of maximum egg mass output

Phase 2

Layer phase 2-High but declining egg production and increasing egg weight-Egg production declines to about 65 percent of maximum

Phase 3

Layer phase 3-Egg production continues to decline below 65 percent of maximum while egg weight decreases only slightly

There is no evidence that nutrient requirements of layers change during the period of lay

Molting

Layers are sometimes molted to extend the production period

Feed and light are restricted during the molt

Can also encourage a molt by nutrient excess or deficiency

Molt can last 3-6 weeks After molt laying resumes

Broilers

Eggs hatch in 21 days Starter diet is similar to layer diet but

more energy dense as broilers grow faster At 3 weeks, broilers are switched to a

lower nutrient density for the next 3-6 weeks

At 7 weeks the finisher diet begins. This diet is lower in nutrients and fed until market weight is reached

Reptiles

Nutrition of Boas and Pythons General Nutrition

Snakes consume whole prey, which makes a balanced diet easy

Balanced Diet Pet snakes usually fed “pinkies” In the wild, snakes eat mammals

birds, other reptiles, fish, wormsamphibians and bugs

Nutrition of Boas and Pythons Graduate from pinkies to mice to

rats to some rabbits

Try not to feed the snake food that is bigger than its midsection

Don’t handle snake after it’s eaten – it may regurgitate

Careful when snake is shedding – it can be aggressive

Nutrition of Boas and Pythons Never feed live prey – can result in

bite wounds

Teaching a snake to eat dead rodents: 1. Jiggle it by the tail and a hungry

snake will eat

2. Don’t use your fingers to dangle the prey – snakebites hurt

Nutrition of Boas and Pythons Feeding Frequency:

Juveniles: feed appropriately sized prey every 6-7 days

Adults: Feed every 7-14 days

Keep log of eating and defecation to monitor snake’s needs and potential illnesses

Nutrition of Boas and Pythons Ball Pythons

Shy feeders who do best with a hide box for shelter

If reluctant to eat, try feeding at night since they’re nocturnal

Imported Ball Pythons may not recognize classic white mouse as prey, so use brown mouse, gerbil or hamster

Nutrition of Boas and Pythons Water

Fresh water available at all times Provide a bowl or tub for them to submerge

themselves in for soaking

Temperature is important 80-95°F degrees for ball pythons

Iguanas

Cold blooded- Increase body temperature for optimum

digestion- Sunbathe for 4 hours- Forage for food after 4 hours of

warming/digestion- High protein requirement- Feeding dog food or cat food can lead

to gout due to uric acid accumulation

Iguana ( cont)

High fiber diets prevent many digestive problems

Vitamin deficiency can lead to pathologic fractures when iguanas are fed diets deficient in Ca and P

Utilize vitamin D3 like birds

Anole Nutrition

Insectivores so diet should consist mostly of insects

Feeder insects should be fed a high quality diet prior to being fed to the anole, this is called “gut loading” of insects ( there are many of these foods on the market)

Crickets, meal worms, houseflies, fruit flies, and silkworm

Anole ( con’t)

Also benefit from fruit nectar Dietary supplements including vitamins D-3

and mineral calcium will also be a benefit Watering can be difficult as anoles in the

wild drink dew and rainwater droplets so they will not utilize a bowl of water

It is recommend to mist the terrarium daily to provide the anole with drinking water

Turtles and Tortoises

All in the group of chelonians All posses a shell Tortoise are generally terrestrial

( however we refer to box turtles and wood turtles)

Turtle generally refers to water turtles Correctly feeding them begins with

identifying what type of chelonian you have

Land Tortoises

African Spur-thighed, Leopard, Star, Red-footed and Yellow-footed are examples

Should be placed outside in warm weather to graze, exercise and bask

( they like to dig, so bury an 8 inch barrier to prevent escape)

Provide sun and shade in enclosure Remove any toxic plants and foreign

material

Sunshine

Vital for turtles and tortoises for synthesis of vitamin D

If unable to provide an outdoor enclosure, provide a full spectrum flourescent light 12 inches or less above the turtle or tortoise

They are unable to absorb Vit D through a window

Tortoise Diet

95% vegetables Majority of vegetables should be dark,

green, leafy like collard, mustard, radish, turnip, kale, cabbage, dandelions, bok choy, broccoli leaves, clover, legumes, cut grass and weeds from yard ( no pesticides)

Small amounts of spinach, swiss chard, beet greens, frozen veggies

Tortoise diet ( cont)

Hibiscus flowers and leaves, grape leaves, carnations, roses, and squash flowers are favorites

Alfalfa pellets can be soaked and offered Fruits are well accepted but mineral poor

and incorrect Ca/P ratio Fruits can form 5% of diet melons, grapes,

apples, oranges, peaches, strawberries, raspberries, bananas with peel etc

Tortoise diet ( cont)

Red and yellow footed can eat more fruit, up to 20 %

Commercial tortoise diets can be soaked an used as a small portion of the diet

Chop entire daily diet of veggies, fruits and commercial diet together to avoid picking and choosing

If you don’t use turtle chow, add Ca supplement daily, vit. Supplement weekly

Offering food/water

Hatchling turtles and tortoises should be fed daily

Adults can be fed every other day or three times a week

Fresh clean water to drink in and soak in First year of life is very important since

they are growing rapidly, it is vital they receive a balanced diet to prevent bone and shell problems

Box Turtles

Fed a diet very different from tortoises Young box turtles will eat primarily

animal material such as earthworms, slugs, snails, beetles, millipedes, spiders, crayfish and grasshoppers

Chopped up pinky mice can also be used for juveniles

Commercial turtle chow can be offered in limited amounts

Box Turtle adults

Will eat plant material including mushrooms, tomatoes, strawberries, raspberries, and other fruits

Should eat about 50% animal protein and 50% plants ( 75% veggies and 25% fruit)

Utilized the fruits and veggies list for tortoises

Finicky Box Turtles

Build the diet around a commercially prepared box turtle chow and add animal and plant material

They need lots of beta carotene ( a precursor of Vit A) in the diet to prevent medical problems

Aquatic Turtles

Red eared sliders, painted turtles, mud and musk turtles, soft shell turtles, snapping turtles

All require clean warm water for swimming

Eat most of their meals in the water ( try to have a separate water dish for eating to prevent fouling of swimming water)

Allow an area where turtle can exit the water to bask

Aquatic Turtle diets

Feed a variety of foods Commercial floating food sticks as a

portion of the diet Small turtles should be offered chopped

earthworms, snails, slugs, shrimp in the shells, chopped up whole fish ( from frozen to kill parasites), chopped mice and gut-loaded insects

Raw chicken, lean beef, liver and gizzards limited

Aquatic turtles ( cont)

As water turtles get older, they will usually consume dark green leafy vegetables, ( see tortoise list)

Older turtles may also consume duckweed, anarchis, algae and some fruits, also offer floating food sticks

Diets too high in protein and other nutrients Shell abnormalities will result Fed exclusively primate chow, dog food

or cat food will usually develop grossly deformed shells, especially the top shell ( the carapace)

Shell may also become domed and misshapen

Obese animals have fat bulging from armpits and groin impeding locomotion

Temperature requirements for turtles and tortoises Correct temperature range for efficient

digestion In addition to poor digestion, they are

prone to many diseases Hibernation is recommended for turtles

and tortoises that hibernate in the wild who are in good physical condition ( consult a vet familiar with hibernating these species)

Iguana Nutrition

Vegetarians specifically foliovores Foliovores consume primarily leaves in

their natural environment Hindgut fermenters which require

microbes to assist in their digestion ( like cows)

Requires a high body temperature which is why iguanas will bask for about 4 hours in the morning before foraging for food

Iguanas in the wild

Eat leaves, fruit, flowers of selected herbs, shrubs, trees and vines

Dietary diversity does not occur on a daily basis

They tend to consume less common plants and seasonally available foods

Iguanas ( cont)

Young iguanas are foliovores just like the adults

All iguanas can develop a taste for inappropriate food items: popcorn, cheese, dog food

Monkey biscuits contain too much D3 which can cause mineralization of internal organs which will cause death

Dog food can lead to gout in iguanas

Appropriate diet size iguanas Hatchlings up to 14 inches finely

chopped food twice a day Older iguanas up to 3 feet in length can

be fed medium chopped food once daily Adults over 2 ½ years of age or over 3

ft in length fed coarsely chopped food every other day

All foods thoroughly washed, chopped and mixed

Composition of the Iguana

Baby iguanas are growing rapidly, incorrect diets can lead to deformed, ill animals

A high percentage of the diet dark-green leafy vegetables

80-90% of the diet should consist of two from this list: collard greens, turnip greens, mustard greens, bok choy, swiss chard, clover, red or green cabbage, water cress, savoy, dandelions, parsley, alfalfa pellets

Composition ( cont)

Beet greens an spinach contain oxalates that may bind dietary calcium should only be offered occassionally

Kale, brussels sprout, broccoli, cabbage, and cauliflower can bind iodine leading to goiter so they should also be limited

The darker outside leaves are more nutritious

Composition ( cont)

10-15 % of diet from frozen mixed veggies, squash, sprouts, carrots, cooked sweet potato, cucumber, okra, parsnips, asparagus, mushrooms, green and red peppers, peas, beans, corn and green beans

Backyard weeds and grasses as forage Fruits can make up the rest of the diet,

they are mineral poor so they are used for flavor

Acceptable fruits for Iguanas Papaya, mango, apple, peach, pear, plum,

strawberry, banana with the skin, raspberry, melon, tomato, grape, raisins, star fruit, kiwi, blueberry and guava

Figs are high in calcium Show grain breads or bran cereals can be

offered sparingly or prepared iguana food can be fed

Light green lettuce can be offered as a treat

Treats

Hibiscus leaves and flowers, rose petals, geranium flowers, carnations and dandelions

Live food is not necessary but some enjoy crickets, meal worms and pinky mice. These should be fed sparingly because they are poor dietary items for this species

Feeding continued

Avoid food preferences by providing 10 different food items in the daily diet and mix them thoroughly to prevent selection of preferred ingredients

Food items should have a positive calcium to phosphorus ratio

Most water is obtained from the diet so feed juicy, moist food

Feeding cont

Offer a large pan of water for soaking Most iguanas relieve themselves in the

water so this will also help keep the enclosure clean

Provide a well balanced diet and only supplement if recommended by your veterinarian. Oversupplementation can be detrimental to the iguana.

Bearded dragons

Omnivores, eating a mixture of invertebrates, vertebrates ( insects and small animals) and plant material

In captivity: feed a combination of insects ( mostly crickets) greens and vegetables

Insects for Bearded dragons Bearded dragons are prone to

impactions of their digestive tract and the chitinous exoskeletons of insect can cause problems

Mealworms can cause impactions so feed them in very limited quantities and avoid them in juveniles

Feed insects that have recently molted so the exoskeleton is soft

Insects ( cont)

Crickets should be no larger than the space between the dragons eyes

Adult dragons can be fed waxworms, silkworms, butterworms, red worms, earthworms, and newly molted mealworms and superworms as treats. Crickets should provide the bulk of the diet. You can occassionally offer a pinky mouse.

Juvenile Bearded Dragons

Should be fed insects more often than adults

Feed at least twice a day, the amount they will eat in 10 minutes

Heat is necessary for digestion so make sure it is appropriate

Greens and vegetables can be available at all times

Insects for Bearded dragons All insects should be gut loaded ( fed

nutritious food that is then passed to the lizard) and lightly dusted with a calcium and Vit D supplement

Dust with a complete multivitamin no more than once a week

Do not feed fireflies or boxelder bugs as they are believed to be toxic to bearded dragons

Greens and Vegetables should make up 20-30% of diet Mixture of green leafy vegetables ex

dandelion greens, collard greens, chickory greens, mustard greens, turnip greens, and parsley

Other vegetables; squash, carrots, green beans, peas, bell peppers

Some fruits: berries, apples, grapes, cantaloupes, papaya, mango, blueberries and bananas

Commercial Diets

Should only be used as a supplement or mixed in with the diet

Long term effects of commercial diets have not been determined