ANS 42 Final

Domestication

• Wild - a species or population adapted to living in its native state

• Humans exert biological and cultural control over generations of animals to select for desired features

• Tame - when an individual animal’s tendency to flee from humans is diminished

• Flight Distance -  how close a human can get to an animal before it flees

• Domestication - adapted to live with humans, parallels natural evolution

• Feral - an individual of a domesticated species that is no longer controlled by human community, breeding, territory, and food supply is no longer regulated by humans, they also cannot become wild again because they are genetically different from their wild ancestors

• archaeological evidence - proportion of age groupings within animal sites, proportion of sexes, morphological changes, artistic representation of animals, objects associated with animal husbandry

• Many species were attempted to be domesticated but failed, by Egyptians 

• Two theories on beginning of domestication

  • Human Initiated - humans wanted pets, however, unlikely, too difficult to domesticate large populations

  • Animal Initiated - animals approach humans for food and safety which lead to coevolution

• Raymond Coppinger - wolf must be taken from den before eyes are open for it to be comfortable enough to be reared in human society

  • corroborates that domestication was animal led as ancient humans would not have had the time to care for a wolf pup

  • Stages of wolf pup development - domesticated dog is ‘locked in’ to one of the stages

    • reactive

    • play

    • heading/stalking

    • heeling

    • mature wolf - never seen in dogs, not neotenic

• Modern day domestication - human led

• Traits that favor domestication 

  • group living

  • social hierarchy

  • males integrated in population with females

  • promiscuous mating

  • males dominant over females

  • signals that show when animals are ready to mate

  • wide acceptance of juveniles in population

  • wide acceptance of different species

  • short flight distance

  • not too disturbed by novel environments

  • flexible diets

  • okay with confinement

• Consequences of domestication

  • Neoteny - retention of juvenile traits of ancestral species in the domesticated adult

  • theory is that juvenile traits were selected for during domestication

  • increased fertility and reproductive activity

  • lower stress levels

  • reduced survival skills

  • increased genetic traits that are unfavorable for survival 

  • Why are juvenile traits desirable?

    • evokes nurturing response

• Dogs and Wolves

  • similar dna makeup

  • same number of chromosomes (78)

  • mitochondrial dna similar 

  • behavior is similar 

  • dogs have - smaller brains, decreased perception of environment, increased skills interpreting human behavior, lowered stress, different colors and bone morphology

Behavior

• There are distinct differences with domestication reflecting genetic change

• Nature - genetic, hormonal, bodily chemical, neurotransmitter influence

• Nurture - environmental influence

• Behavioral Potential - range of possible actions and responses that are governed by genetics but does not define how an individual will behave with precision, genetics are just the boundary of possible reactions and the environment acts within the boundary to influence exhibited behavior

• Domestication changes behavioral potential

• a little stress in an animal’s infancy makes them superior learners

• Socialization - exposure to acclimate an animal

  • needs to be continued throughout an animal’s life

• Imprinting - when a young animal accepts another animal, human, or thing as something to be trusted 

• Animals created social attachments early in life, important to introduce different stimuli in a positive context, individuals who cannot acclimate will not be bred

• Precocial - born/hatched with a high degree of complete independence, all senses are developed

• Altricial - born/hatched dependent upon parent for all life support, and continue to develop after birth

• Feral animals can be socialized if done early  

Modes of Communication

• Communication - the transmission of information that alters the receivers behavior 

• Stereotypy - repetitive behaviors that have no function often seen in captive animals, maladaptive

• Stereotyped behavior - natural behaviors that a species usually shows

• Visual 

  • group structure and establishment of a hierarchy and its maintenance 

  • body posture

  • visual displays

  • Evolutionarily favored for direct communication - not costly in terms of energy

  • Limits - distance, time, obstacles

  • Critical that other individuals in the species recognize the meaning of the display

• Olfactory

  • scent/odor

  • pheromones

  • can be synthesized for informational purposes

  • broken down product of hormones eg. estrogen

  • may be produced by bacteria on an animal

  • effective at long distances

  • long lasting

  • used in site marking

  • Bunting - spreading scent from cheek glands

  • used in group identity

  • most primitive form of communication, even altricial babies can detect it

  • can convey age

• Tactile

  • physical connection

  • mutual grooming

  • aggression 

• Audible/Vocal

  • primates and birds

  • can convey many meanings

  • used for alarm and warning

  • mate selection 

  • aids in escape

  • complex interaction between species

  • dogs prefer high frequency, short, fast, sounds

Form and Function

• Dogs - most genetically engineered species on earth

• Cats - predator that isn’t too different from wild ancestor

  • reinforced ligaments for pouncing

  • can't rotate their paws

  • flexible spine

  • vestigial clavicle that allows for greater reach forward

• Skeleton and Bones

  • genetic and environmental influence 

  • ‘use it or lose it’

  • provides support to animals

  • withstands forces of locomotion

  • reflects function load (digging, flight, etc)

  • bones can withstand 5-7x more force than normal use

  • Bones may be different from animal to animal but mineral and protein composition is usually similar

• Stride length - distance between where one foot lands and the next foot lands

  • larger stride - go farther faster, reduces frictional evidence, fewer touches benefit a predator by being able to capture prey, benefits prey by being able to escape

• Foot form

  • Plantigrade - all foot touches ground eg. humans

  • Digitigrade - balls of feet touch ground eg. Cats, dogs, birds

  • Unguligrade - toes/hoof touches ground eg. Horse, deer, cow, sheep

  • Prey animals are often unguligrade

• Righting reflex - cats land on their feet, they utilize their vestibular apparatus and vision to do so

• Binocular vision - the overlapping of your field of vision, creates 3D vision

• Visual Field - the degree around which you can see eg. Humans - 210 degrees

• Prey have higher visual field

• predators have higher binocular vision

• 3 head types

  • Brachycephalic - short (pug)

  • Mesocephalic - medium (German shepherd)

  • Dolichocephalic - long (greyhound) 

• Photoreceptors detect images and light and are located in the retina

  • Rods - black and white, low light, outer retina

  • Cones - color, bright light, center of retina

• Night vision

  • tapetum lucidum - reflective membrane behind the retina that increases light detection by photoreceptors, causes reflective eyes in photos, a characteristic of nocturnal animals

• Humans have three cones - red, green, and blue while dogs only have two - blues and yellows (Deuteranope) birds have four cones - red, green, blue, UV

• rodents don’t have cones that detect red spectrum light wavelengths

Hearing

• Upright ears collect and funnels sounds, most wild animals have upright ears

Olfactory

• Dogs olfactory bulbs are 3x larger than humans

• dogs nostrils inhale through the center and exhale through the side slits, also moist to allow scent to stick to nose

• they also don’t get used to the smells they’re smelling

Animal Activity

• Diurnal - active during the day

• nocturnal - active at night

• crepuscular - active at transitions from day to night

Pocket Pets

• Rodents have continuously growing incisors, some molar too, that need to be worn down

• Enamel - hard outside of tooth

• Dentin - soft inside of tooth

• Malocclusion - improper tooth alignment 

• Rodents are often burrowers with tubular bodies and nocturnal

• Hamster

  • syria desert region

  • body conserves water, urine is concentrated, less odor

  • large cheek pockets

  • poor eyesight

  • solitary

• Guinea Pig

  • peru

  • does not tolerate temperature change well

  • body is designed to run

  • crepuscular

  • social

  • easily panicked

• Mouse

  • asia

  • ample water

  • not aggressive unless scared

  • urinates frequently, sensitive to ammonia

  • nocturnal

  • social with a hierarchy

• Rat

  • asia

  • nocturnal but opportunistic

  • adaptable

  • social

  • flexible hierarchy

  • sweat through tails and paws

• Chinchilla

  • south American mountains

  • not aggressive but will project urine 2-3 feet if annoyed

  • dust baths for fur

  • nocturnal/crepuscular

  • subject to heat stroke 

  • social

• Gerbil

  • mongolia

  • tolerates extreme temperatures

  • nocturnal

  • monogamous

  • illegal in CA

• Rabbit

  • lagomorph 

  • Western Europe and North Africa 

  • flee response

  • crepuscular 

  • subject to heat stroke

  • social

  • plantigrade

  • strict hierarchy

  • lightweight skeleton

• Ferret 

  • Europe 

  • protected grain supplies

  • anal scent glands

  • burrowers

  • olfactory communication

  • nocturnal but opportunistic

  • solitary but social now that domestic

  • prone to cancer and heat stress

  • biotic invasion

• Albino - genetic mutation that reduces/eliminates pigments so fur is white and iris looks red due to visibility of blood vessels

• Tail slipping - tail skin can slip off if grasped and animal weight hangs down

Pet species

• mammals - mammary glands, milk

• avian - feathers

• reptiles - scales + breathe air

• fish - scales, no limbs, gills, water living

• amphibians - gill in larvae stage, land in adult stage

Birds

• Archaeopteryx - earliest known bird ancestor

• furcula - fused clavicle

• weight needs to be minimized for flight

• drag needs to be minimized

• lift needs to be maximized - keeps in air

• thrust needs to be maximized - maintains lift, counteracts drag

• wing loading = body mass/wing area

• body weight is relative to wing area

• lift is generated by flow of air over wing, larger area = more flow = more lift

• flapping wings requires muscle and muscle has weight, more energy needed

• requires 50-75% more energy than a same sized mammal

• and requires 1.5-3x more oxygen

• birds are homogenous in essential structure, streamlined, aerodynamic 

• flightless birds are descended from flight birds, wings are vestigial

requirements for flight: 

• reduction of body weight- thin skin, fewer and fused bones, thinner bones, hollow bones, some are pneumatic (used in respiration), no bladder (paste excrement, uric acid), reproductive tract only active and developed during reproductive season, lay eggs, no teeth

• commitment of forelimb to flight- arm bones fused to create wing, specialized chest pectorals for flight (up to 50% body weight), modified sternum (keel), accentuated vision and balance (eyes up to ⅓ of head, more photoreceptors, 4 types of cones, more developed vestibular apparatus) enhanced respiratory and circulatory systems (better are extracting oxygen from air, rigid lungs, air sacs expand throughout body, makes them susceptible to airborne toxins [canary in coal mine])

• trimming of primary feathers reduces thrust 

• evolutionary adaptation - birds will not show illness, as other birds will ostracize a sick bird

Fish

• 3rd most popular pet

• fish industry sells aesthetics

• originated in china for both food and aesthetics

• fish in rice paddies resulted in better rice yield and fish available for consumption

• common carp - koi

• prussian carp - goldfish

Goldfish

• Tang Dynasty - genetic mutation in Prussian carp caused gold scales, considered sacred

• Song Dynasty - only imperial family were allowed goldfish 

• Ming Dynasty - ceramic goldfish containers, begin to be raised indoors, led to selection of traits that would not survive outdoors

• Europe acquired in 1600s - thought to bring good fortune

  • permissible characteristics

    • freshwater

    • cold water ~68 degrees F

    • omnivores

    • nonagressive

    • hardy (change 25% of water every 1-2 weeks

• US in 1874

• Shifted from China to Japan

Koi

• Ornamental pond species

• began ~200 years ago from golden carp

Modern Home Aquaria

• Biological  filtration for balanced aquarium 1850s

• electricity in 1920’s

• Air transportation and compressed air WWII

• Aeration - airstones, sub gravel filters

• immersion heaters

• community tanks - many types of fish in one tank

Saltwater Aquariums

• Silicone glue allowed for saltwater tanks as before, tanks were secured with metal edges that would rust if exposed to salt water

• ~10% volume of sales 25% value of total sales ($400-600/lb)

• most saltwater fish are imported and exported from the wild

  • issues: degradation of reefs due to physical damage by collectors and gear, sometimes dynamite

Freshwater

• 90% volume, 75% value

• imported from Southeast Asia, india, and South America 

• florida and Hawaii are domestic culture locations (warm)

Advantages to captive bred

• Accustomed to people

• acclimated to aquarium life

• offspring easier to rear

• always young fish

• less shipping stress

• fewer parasites

• better for environment 

• only about 100 saltwater fish are captive bred worldwide and 30 in US

Reptiles (Dr. DeNardo)

• Squamates - snakes and lizards

• chelonians - turtles and tortoises

• crocodilians - crocodiles and alligators 

• ancestrally, closest living reptiles to birds are crocodiles

• feathers are modified scales

• Can live in deserts and jungles

• not domesticated

• homeotherm - same temperature over time

• poikilotherm - varied temperature over time

• endotherm - heat is generated by animal

• ectotherm - heat is gained from environment

• Reptiles are warm blooded homeothermic ectotherms

• reptiles should stay in between thermal maximum and minimum for optimal performance

• Cool morning - lizard presses itself on dark rock perpendicular to the sun, it has a dark color, increased heart rate, and increased blood flow to its backside

• Warm midday - lizard standing with body off of rock, facing sun, open mouth, light color, reduced blood flow

• hot afternoon - escapes to burrow

Zoonotics

• Definition: diseases transmitted from animals to humans that pose a threat to human health

• Methods of transmission include

  • bites

  • scratches

  • direct contact

  • ingestion

  • inhalation

• Infectious agents on an inanimate object is called a fomite

• Zooanthroponosis - when humans give an animal a disease

• Zoonoses are categorized by their causative agents

  • viral - reproduce in living cells

  • bacterial - single celled organisms

  • fungal

  • parasitic 

• Zoonotics have the most significant impact on the young, old, and immunocompromised 

Viral Zoonotics

• Rabies

  • on every continent except Antarctica

  • Enzootic - a geographical region having a reservoir of the zoonotic agent in the animal population

    • considered enzootic because the wild animals in US have the disease and can spread it to humans

  • all mammals are susceptible but more common in carnivores

  • transmitted by bite, inhalation, ingestion, and exposure to open wounds

  • travels up nerves to brain and salivary glands

    • replicates in brain causing damage and increased salivation

  • the deeper and closer to the brain the wound is, the faster the progression

  • in dogs and cats it lasts 2-8 weeks but up to 6 months, up to 1 year in humans 

  • Symptomology - reflects replication in brain and brain damage 

    • prodromal - anxiety, nervousness

    • excitatory - excitement, aggression, hydrophobia (furious rabies) lasts up to two days

    • paralytic - limbs and body becomes paralyzed including lungs

  • once symptoms are expressed 99% certain death

  • a definitive diagnosis comes from an autopsy (necropsy) of the animal’s brain

  • prophylaxis- vaccination for pets and humans at high risk, also a post exposure vaccine

• Newcastle Disease

  • transmission - aerosols

  • affects primarily domestic fowl (ducks and geese are more resistant)

  • symptoms - depressed growth, tremors, respiratory impairment

  • human threat - conjunctivitis, flu symptoms 

  • no treatment

  • prevention - vaccination

• Western Equine Encephalomyelitis 

  • transmission - mosquito bite

  • affects - many animals, including reptiles and amphibians, though only horses and humans show symptoms

  • Symptoms - horses: inflammation of brain, lack of coordination, up to 50% mortality humans: children could get permanent brain damage from inflammation

  • prevention - vaccinations

Bacterial Zoonotics

• Psittacosis (parrot fever) chlamydia

  • transmission - aerosol 

  • affects birds

  • symptoms - diarrhea, respiratory infection, stress causes progression of disease

  • human threat - generally asymptomatic but some flue like

  • treatment - tetracyclines from diet

  • prevention - cleanliness

• Salmonella

  • Transmission - ingestion

  • affects all animals

    • 1-3% of all domestic animals, 37% of reptiles in Washington zoo

  • symptoms - asymptomatic to gastroenteritis, can cause mortality, dehydration is dangerous

  • treatment - antibiotics, in humans it is self limiting

  • prevention - “treat and delete”

  • typhoid fever is a subcategory 

  • CDC estimates 1.35 million cases 

    • 26,500 hospitalizations

    • 420 deaths / year in US

  • found on food and reptiles have the most severe strain

  • reptiles also carry botulism toxin

  • Bartonella Henselae (cat scratch fever)

  • Transmission - scratch or bite 

  • cats are usually asymptomatic

  • human threat - swollen lymph nodes, fever, rash but is self limiting in 2-6 months

  • prevention - keep cats indoors, clean all wounds from cat

Fungal Zoonotics

• Ringworm (Dermatophytosis)

  • transmission - direct contact or fomites

  • not a worm - a fungus

  • affects dogs, cats, rodents, livestock, and people

  • thrives in moist environments

  • symptoms - raised circular ring on skin, scaly, itchy

    • cats - head

    • dogs - trunk

    • mice - head and body

    • human - anywhere

  • treatment - topical fungicide, self limiting in humans in about 4 months but reinfection is prevalent

  • spores can live up to 18 months

  • prevention - dilute bleach 1:10 clean surfaces

  • fluoresces green under black light 

Parasitic Zoonotics

• Toxoplasmosis

  • protozoa is called toxoplasma gondii

  • transmission - ingestion

  • complex life cycle that includes infective form and oocysts that form cysts in tissue

  • affects mammals and birds 

  • cats are a complete host as it can complete a full life cycle in a cat and can shed its infective form through a cats feces

  • cats get it by eating a rodent with a cyst, it will begin to shed the infective form in about 2 weeks, the fecal matter a human may ingest leads to human infection

  • a woman who is pregnant in the first trimester who gets infected for the first time will develop birth defects

  • in US 11% of people have already been infected

    • up to 60% in other parts of the world

  • cat feces in natural water sources can infect rodents, birds and sea otters

  • symptoms - cats and dogs get diarrhea, humans have flue like symptoms, and sea otters can get lethal neurological damage

  • prevention - cook meat, boil camping water, blood test for pregnant woman

• Worms

  • tapeworms, hookworms, pentastomida

  • transmission - ingestion 

Nutrition

• Nutrient - substance that is consumed, provides nourishment, used for growth and maintenance of life

• herbivore - an animal that does best when consuming plant derived foods

  • unguligrades, elephants, tortoises, rabbits

• carnivore - an animal that does best when consuming animal derived foods

  • cats, snakes, most fish

• omnivore - consumes both plant and animal foods

  • humans, dogs, mice, rats

• obligate - must consume a particular type of food to thrive and meet all growth and maintenance needs

  • rabbit - obligate herbivore

  • cat - obligate carnivore

  • you cannot have an obligate omnivore 

• essential - refers to elements that must be consumed from the diet because the animal cannot synthesize them in their body

  • vitamin C in humans and guinea pigs

• 6 categories of nutrients

  • water

    • most important

    • average mammal is 60% water

  • vitamins

    • organic molecules that assist in bodily functions (blood clotting)

    • some are fat soluble (A,D,E,K)

    • some are water soluble (B,C)

    • there are about 14 essential ones

  • minerals

    • inorganic molecules that assist in bodily functions (enzymes, hormones)

    • provide strength and structure (calcium in bones)

    • about 20 essential ones 

  • Lipids

    • provide energy, a storage form of energy

    • basis of the cell membrane

    • important for metabolic processes and signaling

    • hormone precursors

    • provides insulation

    • aids in the absorption of fat soluble vitamins

    • role in cellular function is critical 

    • carbon and hydrogen chains connected through bonds

      • end of chain is carboxylic acid group

    • carbon has four binding sites, if all are bound it si a saturated fat, if 2 binding sites are bound to the same molecule (Double bond) it is an unsaturated fat

      • saturated - solid at room temperature

      • unsaturated - liquid at room temperature

        • double bonds created bends and angles in the molecule

    • saturated and unsaturated fats influence fluidity of cell membranes

    • cellular signaling requires molecules in membrane to move about

    • Omega 6 and Omega 3 fatty acids

      • carbons are numbered sequentially from carboxylic acid end 

      • the end of a fatty acid without carboxylic acid is called the omega end

    • essential fatty acid - unsaturated

    • most animals can add carbon atom as and double bonds once they have the starting essential unsaturated fatty acid

    • cats needs more fatty acid types because they don’t have the enzyme to synthesize one unsaturated fat into another - cause for obligate carnivore

    • Linoleic acid -> enzyme in body adds double bond - gamma linoleic acid -> enzymes in body add double bond and more carbons - arachidonic acid

    • free radicals are formed in normal body processes but also from toxicants such as cigarette smoke

    • they attack double bonds (rancidification / oxidation)

    • break down the molecule, no longer the essential volatile fatty acid (VFA)

    • antioxidants protect the essential fatty acids from rancidification

    • chemical forms: BHT, BHA, Ethoxyquin

    • natural forms: vitamin C, vitamin E

    • these are also needed for bodily functions, so you need an excess amount for them to also act as antioxidants 

    • antioxidants can also protect against cancer and improve cognitive functions

    • fatty acids improve the palatability of foods

    • dogs are highly sensitive

    • Deficiencies result in dry skin and coats and impact cell membrane function, reproduction is also reduced, there are vision and neurological problems, and reduced immune function

  • Proteins

    • building blocks for muscle and tissue

    • enzymes, hormones and cell signaling

    • amino acids come from broken down proteins

      • 8 essentials

    • in excess it is an energy source, but you must remove the amino group first

    • amino groups have nitrogen

      • becomes toxic ammonia if accumulated

      • expelled through urine

  • Carbohydrates

    • provide energy

    • large molecules are made of sugar 

    • complex carbohydrates are broken down more slowly vs simple sugar

Teeth

• Humans and plant eaters have teeth designed for chewing

• dogs and cats have teeth designed for ripping and shredding

  • their stomach acid is stronger to cope with larger chunks of tissue

Digestion

• GI tract reflects your diet

  • a simpler tract is related to a nutrient dense diet

  • complex tract is related to a dilute nutrient diet

• the more complex the tract, the more time food stays in the tract, therefore, more time to utilize the nutrients

  • usually plant based diets

• Energy Storage forms: lipid, protein, carbohydrates

  • protein and carbs have the same amount of energy

Diets

• Adults

  • need nutrients for maintenance

  • primary need is energy

  • activity level of animal influences need

• young / growing

  • need maintenance and more for growth

  • food usually more expensive because it has more nutrients and higher quality ingredients

• quality - the bioavailability of nutrients in the food

• high quality protein is usually from animals

• low quality protein is usually from plants, harder to digest

• cat food is expensive because they require more protein as they are obligate carnivores

• AAFCO - association of American feed control officials

  • set pet food standards of nutrition

  • clear and consistent labeling

  • only regulate dog and cat food

  • requires a statement saying either:

    • the food was tested and the animals did well, meets nutrition standards

    • food was formulated to meet the nutritional standards of

• If an animal does not have all of its essential nutrients, it can develop health disorders

  • deficiency in arginine: leads to ammonia build up

  • deficiency in taurine: leads to decreased reproduction, blindness, cardiac problems

  • most health problems in lizards and turtles are from dietary deficiencies

• high quality food reduces anxiety behavior in shelter dogs

  • reduced yawning, nose licking, sweaty paws

• excessive fish food allows nutrients to leach into water, feeding the bacteria, increasing pH, this is detrimental to fish

  • feed fish 1-5% of body weight, or what they can eat in about 3 minutes 

• Overfeeding leads to obesity

  • should be able to feel ribs

  • reduces lifespan

  • increases joint loading (increased chance of arthritis)

  • exacerbates complex genetic traits

    • skeletal abnormalities

    • osteochondritis dissecans - cartilage flakes off of joints

    • hip dysplasia - ball joint of femurs doesn’t fit in socket

  • an overweight puppy will have joint issues as the extra body weight is pressing on growing joints

• chocolate contains Theobromine

  • diuretic

  • related to caffeine

  • a neurotoxin that affects heart rate and the CNS

  • dangerous because it metabolizes slowly, causing a longer acting reaction

  • dark chocolate has more theobromine

• Onion contains and alkaloid (n-propyl disulfide)

  • yummy flavor 

  • can cause hemolytic anemia

    • dark urine

    • fever

    • lack of oxygen

  • cooked onion is still dangerous

• egg is ideal food

  • contains all materials needed to develop a neonate

  • also contains compounds to protect developing embryo such as:

    • Avidin

      • antibacterial agent that is secreted into egg white

      • tightly binds with essential B vitamin Biotin

        • B vitamin involved in metabolic pathways such as fatty acid synthesis 

      • when bonded with biotin, the biotin becomes no longer available 

      • excess avidin can cause a biotin deficiency 

        • cooking destroys avidin and reduces salmonella risk

        • although biotin is in the shell of an egg, it might not be enough to compensate for the amounts of avidin in the egg white

• Cats lack the ability to taste sweet, they don’t eat carbs

Pocket Pets

• Ferret - carnivore and illegal in CA

  • simple GI tract, 3-4 transit time

• hamster - omnivore 

  • has fore-stomach like a cow

  • has cecum

• mini pig - omnivore

  • can grow too fast with normal hog food

• mouse - omnivore and opportunistic

• gerbil - granivore and illegal in CA

• chinchilla - herbivore

• Rabbit - obligate herbivore

  • complex GI tract

  • hind gut fermenter

  • need hard pellets to wear down teeth

  • intakes food, arrives at glandular stomach to digest food, enters small intestine that absorbs water soluble nutrients, fiber is passed to large intestine and is sorted by size, small fiber goes to cecum, large fiber is excreted

  • the cecum ferments the fiber that is indigestible and produces vitamins, VFAs, and essential amino acids

  • excreted cecal pellets contain important nutrients and are reconsumed (coprophagy)

  • diets that are too high in protein, energy, or too low in fiber can result in excess pellets

• pygmy hedgehog - insectivore and illegal in CA

  • also likes to eat snails, snakes, and worms

• Rodents have continuously growing teeth (open-rooted)

  • grows ¼ to ½ inches per month

  • risk of malocclusion

Feeding Methods

• Ad libitum - free choice

• limit feeding - best for rabbits, ferrets, and mini pigs that wont limit themselves

• limit treats as they could lead to obesity and tooth decay

• certain species will spit food into their water, careful with sipper tubes, breeding ground for bacteria

Bird Nutrition

• Digest quickly to keep body weight down

• Food moves from mouth to crop

  • crop stores food

  • expands and if contracted, sends hunger signals

• then moves from crop to proventriculus (glandular stomach)

• then moves from proventriculus to gizzard which grinds food with sand and small rocks

• birds also have a ceca that produces VFAs

• birds regurgitate food for babies from crop

• Tom Roudybush - cockatiel experiment UCD alum

  • baby birds need more dilute food when younger and more solid food as they get older

  • baby cockatiels had to be separated from each other during the study or else they would feed each other

  • found that they need 20% protein for best health

• changing a bird’s diet is not easy, they may not recognize they new food as a food

Feather Color

• Pigment can come directly from food

  • canary should eat foods rich in beta-carotene and canthaxanthin

  • flamingos eat canthaxanthin

  • canthaxanthin comes from crustaceans

    • reason shrimps change color when cooked

• pigment can also come from the metabolism of food

  • most parrots (psittacine) colors

  • change of feather color indicates nutritional completeness of diet

• achromatosis - lacking pigment

  • lysine deficiency - an essential amino acid that causes achromatosis in turkeys, quail, rats

    • Not the cause for achromatosis in cockatiels - that is a B vitamin deficiency

    • instead, lysine deficiency causes decreased growth and body fat 

Genetic Information 

• Genetic information is carried in dna

• dna is structured into chromosomes

• chromosomes are found in the nucleus of every cell

• bases make up dna and are compressed to fit into the nucleus 

• each chromosome is paired (Diploid)

• reproduction - meiosis makes sex cells

• gametes - sperm and egg, haploid (only one of each)

• gene - the units of dna that encode a product/trait

  • encoded by a specific base order

  • located at unique places on a chromosome with a constant locus

• alternate versions of genes are called alleles

  • represent differences in base sequence of dna

  • arise through mutation

  • we can select for desired traits due to genetic differences that can be replicated in a new generation

• if alleles are the same on the two chromosomes that make up the diploid pair they are homozygous

• if they are different they are heterozygous

• an individual will have at most 2 copies of a gene, but a population has many more alleles available

• mutations can be positive or negative or neutral

  • positive mutation: improves survival, fitness, and reproductive success

  • negative mutation: reduces survival, fitness, and reproductive success

  • neutral mutation: no impact

• one allele can completely overshadow another

  • dominant and recessive

• different genotypes can produce equivalent phenotypes

  • Bb BB (B_)

• multiple alleles for a given gene are given superscripts to denote differences 

  • may be a hierarchy with various alleles being dominant or recessive to each other

• Incomplete dominance - alleles may not be fully dominant or recessive, creates a blended appearance 

• Merle gene - MM influences color pattern but linked with auditory and ophthalmologic abnormalities

• Codominance - each allele is expressed in the phenotype 

• Wildtype is a trait seen in the ancestral population, does not equate to dominant or recessive

  • reflects higher frequency of that allele in ancestral population

• traits are characterized as simple/qualitative or complex/quantitative/polygenic

  • simple: governed by a single gene

  • complex: governed by many genes, can be quantified numerically, may be influenced by the environment

• Epistasis - represents one gene that influences the expression of another gene eg. Albino

• Melanocytes - specialized cells that produce pigment

  • must exist and function properly to generate melanin

• Melanin - pigment that gives skin, hair, and eyes their color

• W gene - White

  • governs melanocyte migration to the skin and replication of melanin

• C gene - body color, full color

  • Encodes tyrosinase, an enzyme involved in making pigment

• A white cat is an example of epistasis has W_ gene that causes no/few melanocytes to exist

• Melanocytes also play a role in hearing, less melanocytes = worse hearing

• Mendel’s laws of inheritance

  • Law of segregation

    • a gamete gets only a single allele for any gene because a gamete carries only one copy of a chromosome

  • Law of independent assortment

    • genes assort into gametes randomly

    • independent from what happens in other gametes

• During meiosis, 2 chromosomes can cross over (homologous recombination) alleles of one gene have the possibility of being associated with either allele of another gene

• genes physically close together cannot cross over with each other because they are ‘linked genes’ and travel together 

• Test cross - when genotype is unknown, breed to a known (recessive) genotype

• Sex chromosomes - associated with determining the biological sex of an individual 

• Heterogametic - XY

• Homogametic - XX

• Birds female is heterogametic ZW

• some species are non sex chromosome regulated sex

  • gene dosage (number of a given gene)

  • temperature of development

  • sixe and society (like clownfish)

• Autosomes - not sex chromosomes

• Sex linked traits

  • if a trait is on the X in a male, there is nothing on the Y to stop the X trait from being expressed, can be harmful

  • females may have second copy that will compensate

  • females ‘turn down’ expression in one of the X chromosomes called Inactivated X, randomly selected

• fixing alleles - make gene homozygous for preferred traits (can be done by selective breeding)

  • reduces heterozygosity

• breeding true - breeding two members of the same breed produces only that breed, can inadvertently fix alleles for undesirable or even deleterious traits

• Hybrid Vigor / Heterosis

  • increased vigor or superior qualities arising from cross breeding genetically different animals (AA with aa)

  • if exhibited would be seen in first generation but not in subsequent generations because the parental lines are no longer homozygous for different traits

• Genetic Disorders

  • simple or complex

  • if recessive, dominant phenotype may carry recessive mutation

  • unobvious diseases may unintentionally be bred

  • can be autosomal or sex linked

  • disorders occur with higher frequency among related individuals, increased homozygosity leads to more diseases since a majority of genetic disorders are recessive

  • check if both sexes are affected to determine if a trait is sex linked

  • Sex limited - only able to be seen in one sex but can be passed on by both sexes

  • Consistent age of onset and progression of trait shows genetic control, also transcends environmental influence

  • disorder affects same anatomical location - shows genetic control

  • disorder associated with a change in chromosome shows genetic control

  • disorder associated with an abnormal protein product that can be measure shows genetic control eg. Lactose intolerance 

Breeding and Reproduction

• Breeding Strategies

  • inbreeding

  • line breeding - not as related as inbreeding but still related

  • phenotypic breeding - similar feature to continue desired look

  • outcross

  • compensatory

• Breeding Goals

  • particular characteristics 

  • preserve species

  • reduce deleterious traits

  • maintain variability

• Reproduction

  • genetic diversity

    • variability for inhabiting different niches

    • humans can select for traits 

  • sexual reproduction

    • Combining genetic material from individuals (gametes)

  • asexual reproduction

    • copying own genetic information (no gametes)

  • Fertilization

    • fusion of gametes that permits variability

  • generalized anatomical features in reproductive tracts

    • gonad - site of meiosis and gamete production

    • ductwork - transportation of ova out of female, most specialized as it reflects reproduction method

  • External fertilization

    • fertilization outside of the body

    • release gametes into the environment

    • risky

    • Large quantities of gametes released

  • Internal fertilization

    • requires specialized organs

    • requires adaptation of females ductwork to receive sperm

• Site of Development

  • Oviparous

    • egg birth

    • zygote develops in shell

    • embryonic development happens outside of mothers body

    • species with external fertilization must be oviparous 

    • some species with internal fertilization are also oviparous 

    • ductwork is modified to add all resources and the shell

    • waste from protein is stored until hatch, uric acid is less toxic, also uses less water

    • sperm stored for fertilization before shell components added

  • Viviparous 

    • live birth

    • embryonic development inside of mothers body

    • connection to mother for continuous nourishment

    • gamete is small

    • ductwork is modified to include uterus for a placenta to attach

    • must have internal fertilization

  • Ovoviviparous

    • Zygote develops inside shell, shell is in mothers body

    • not connected to the mothers body

    • all resource inside shell

    • modified ductwork to add resources within shell and provide place for eggs to incubate

    • hatch internally, live birth

    • sperm stored for fertilization before shell components added

  • Ovary

    • site of gamete production

    • developing ova are called oocytes

    • oocytes mature in the follicles

    • release of ova from the ovary is ovulation

    • not all eggs become viable

    • growth and maturation of ova is under hormonal control - FSH

    • released of mature ova is also under hormonal control - LH

  • Hormones

    • from the hypothalamus - GnRH

    • from the pituitary gland made in response to GnRH - FSH and LH

    • ovary produces sex steroids estrogen and progesterone 

    • Environmental cues activate GnRH

  • Estrogen

    • cooperates with FSH and LH to mature the developing oocytes to become ova

    • prepares female tract for reproductive activity

    • influences reproductive behavior 

  • Progesterone 

    • in most viviparous species it is involved in pregnancy maintenance and mammary gland development 

Reproductive cycles

• Photoperiodism impacts reproductive cycle

  • most potent cue for reproduction 

  • responsible for time of sexual receptivity

  • in equatorial species, rainfall is the cue

  • in some reptiles and fish, temperature is the cue

• Cyclicity of reproduction

  • reflects activity of the ovary

  • Puberty - gonads initiate function

  • Estrus - maximal sexual receptivity 

  • Estrous Cycle - time frame of one estrus to the next

  • Anestrus - ovary is inactive

• Estrus Cycles

  • polyestrous - repeated estrous cycles, ovary is never inactive once puberty starts

  • seasonally polyestrous - repeated estrous cycles during particular season, if it isn’t the right season they go into anestrus 

  • Monestrous - single estrus event 

• opportunistic breeders - breeding relies on environmental  cues and will breed whenever possible eg. Rabbits

• Litter bearing -  multiple follicles mature and ovulate at the same time in response to LH surge

• Single offspring - single follicle ovulates at one time

• Spontaneous ovulation - surge of LH occurs spontaneously during estrus cycle

• Induced ovulation - physical stimulation must occur to release ova

• if a ferret isn’t stimulated it can get sick and die

• Puberty - when gonads initiate function due to maybe, body size, fat %, nutrition availability 

Behavior 

• Cat becomes restless when active

• urinates more

• decreased appetite

• vocalizes 

• exhibits lordosis

Reproduction of Companion Birds

• Seasonal breeding

• monogamous 

• often migratory

• altricial

• Chiken

  • sedentary

  • polygenous

  • precocial 

• Birds are seasonally active but eyes aren’t required to detect light

  • use photoreceptors inside brain, thin skull allows light to penetrate

  • long daylight hours cause bird testes growth

• when bird ovary is active appears to be a ‘cluster of grapes’

  • size of ovary reflects amount of yolk present

• Hen - female bird

  • Can be laying or non laying

• yolk size increase occurs before fertilization

  • made of lipoproteins from the liver

  • a laying hen serum contains high fatty acids, vitellogenins, and calcium

Egg Formation

• Oviduct

  • long tubular organ that collects ova and creates the egg

• Infundibulum

  • once ova are ovulated, the infundibulum funnels the captured ova into oviduct, the site of the secondary sperm storage tubules

• Magnum 

  • the largest section

  • deposits albumen proteins (egg white) and other egg white components (avidin) it form the aqueous gel and the chalaza

• Isthmus

  • 2 membranes are added around the albumen, formation of initial calcification 

• Shell Gland 

  • rehydration of egg white ‘plumping gland’

  • addition of pigment (ooporphyrins)

  • the shell’s calcium comes from medullary bone storage 

• Utero-Vaginal Junction

  • site of primary sperm storage

  • sperm moved daily to infundibulum

  • oviposition (laying of egg)

• Cloaca 

  • single exit for GI and reproductive tract, no bladder, solid uric acid

Male Reproduction

• Gonad - site of gamete (testis)

• Ductwork - tract for gamete transfer

  • modified based on site of fertilization

• Same hormones in play as females

• Temperature is critical for sperm production outside scrotum allows for cooler temperature 

• Failure of testis to descend is called Cryptorchidism

  • genetic

  • can be unilateral or bilateral, unilateral still fertile

• Males produce new sperm throughout their lives

• Os Penis (Baculum)

  • a thin bone within the penis that provides structure

  • in most animals

• Reptiles have hemipenes - 2 penises 

• Bulbus Glandis in dogs - physically locks penis inside of female by becoming enlarged

More Reproduction Facts

• Olfaction plays a role in reproduction

  • vomeronasal organ is present in many animals on the palate of their mouth

  • Flehman response - raised lip, chattering, intentional, believed to help draw scents into vomeronasal organ

• Scents like pheromones increase sexual behavior 

  • can stimulate engorgement of intromittent or copulatory organ

  • can interrupt pregnancy - Bruce Effect

    • scent of other male rodent detected early in female rodent pregnancy can cause abortion of babies

  • can synchronize female estrus to allow impregnation of  multiple females at once (Whitten Effect)

• Evidence of breeding - vaginal plug of coagulated semen in small rodents

• Implantation - zygote implants in uterus to develop nutrient supply and establishes placenta

  • can be delayed to attach at a better time for fetal development

  • mice up to 10 days, kangaroo up to 1 year

• Pseudopregnancy - following ovulation, the remainder of the follicle (corpus luteum) on the ovary develops and secretes pregnancy hormone progesterone even in absence of embryo feedback

  • driven by hormones

  • a ‘birth’ happens, lactation occurs

  • believed to be helpful for group lactation

• Hens may exhibit broody behavior without eggs present

• Symphysis Pubis - cartilage joint between the wings of the pelvis

  • stretches during birth

  • guinea pig must give birth before 8 months of age to stretch the symphysis pubis

  • will stay stretched after birth

  • will fuse without birth

• Hamsters can suffocate their young by hiding then in their cheek pouches if disturbed after delivery