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OSU / Animal Sciences / ANIMSCI 2200 / Many animal fibers are being replaced by what?

Many animal fibers are being replaced by what?

Many animal fibers are being replaced by what?


School: Ohio State University
Department: Animal Sciences
Course: Introductory Animal Sciences
Professor: Pasha peffer
Term: Fall 2016
Tags: IntroductiontoAnimalSciences, Animal Science, introductiontoanimalscience, animal, and animalsciences
Cost: 50
Name: intro animal science final exam study guide
Description: these notes cover most of the final and then some extra. use this study guide as a tool for the final, but also consult your book and power points/ notes from class.
Uploaded: 12/10/2016
22 Pages 152 Views 4 Unlocks

Final Exam study guide  

Many animal fibers are being replaced by what?

• Chapter One Importance of Animals

Key points:

We rely on animals for food, clothing, knowledge, energy, power, status,  transportation, companionship, entertainment, service and capital

Development complex of the human brain: we originally ate a plant base diet, so had a large gut. Once we found out how to eat and digest meat, out  gut shrank and digestion was less labor intensive, and also took less  energy. This energy then went to the brain.

•Meat/ dairy consumption: our diet should contain low-fat meat as well as  dairy products such as milk  

Yogurt and cheese.

In the US, 99% consume animal products (this includes eggs, honey, gelatin,  etc.)

27% of the US’s calories (on average) are from animal products, excluding  animal fats  

What animals are the most used in research?

17% of the worlds calories (on average) are from animal products excluding  animal fats.

Meat and milk is the greatest contribution to animal products consumed in  the us and world wide

Developed countries consume at least twice the amount of meat and egg  product when compared to least developed countries, this  pattern of economic status influencing food choice is also seen in each  individual country as well. We also discuss several other topics like What does oligopoly denote?

Worldwide goat is the most consumed meat

Today chicken, beef and pork are the most consumed meats in the US, with  pork being the number one consumed meat.  If you want to learn more check out What does altruistic behavior mean?
We also discuss several other topics like What is the chemical symbol of nitrogen?

Milk consumption has decreased overall but cheese consumption has  increased.

Milk in the us is mostly consumed from cattle, but in India over 60% of people get their milk from water buffaloes.

Define metabolism.

Other animals used in milk production are: yaks, goat, sheep, camel, mare,  sow, reindeer and llama  

•Other uses for animals beyond food:

Fiber: Many types of fibers can be collected from animals including wool, from sheep, mohair and cashmere from goats, angora from rabbits and other  fibers from llamas, alpacas, camels and yaks.

Many animal fibers are being replaced by cotton or synthetic fibers.

Globally, wool is the most used animal fiber, representing 5% of the textile  fiber production.

Land management and transportation: animals all across the globe are used  as erosion control, range or pasture management including plant diversification and noxious weed control. If you want to learn more check out 1 kilogram is how many milligrams?

Many grazing animals can be sustained on land which otherwise would have  not been cultivated

Draft animals are vital especially in Africa and Asia, where most of the land is  not able to be cultivated by machine. Up to 25% of the land relies on  animals to cultivate the land.  

Transportation using animals is also important; some areas in the united  states have limited number of cars so rely on animals for transportation.  

In Sub-Saharan Africa, donkey driven carts have been on the rise, and are  expected to stay in demand in the future.

Some animal fats can be refined and used as fuel for cars.

Research: animals have contributed to over 50% of the scientific discoveries  and 2/3 of the Nobel piece prizes  

Rats and mice are the most used animals in research, but other animals used  are non- human primates, dogs, cats, pigs horses, etc.

By FEDERAL LAW animal testing MUST be conducted before human trials are  conducted. 

Rats and animals are used due to convenience; they take up a small amount  of space, reproduce fast and are easy to maintain.

Pigs have contributed quite a bit too, due to our similarities with them; we  have had heart studies and obesity studies done on pigs which correlate  to humans. This also includes heart disease.

Sheep studies have been used in fetal development studies, and chickens are helping in studies with ovarian cancer.  If you want to learn more check out Preformation means what?

It is important to use animals for research; no animal is a perfect model for  humans. The results we get from these studies may give us insight to

possible results, but until the clinical trials are conducted there is not  “for sure” reaction.  

Chapter Two Domestication:

Key points:  

Humans are not solely responsible for the domestication process; evolution  and genetics have some place in.

the first stage of evolution is the longest stage of development, and is  considered the origins of animals and their continuing ability over time,  while domestication is considered fixed evolutionary behaviors  and production is the most recent stage of development through selective  practices.

All domesticated animals have similar traits, which allowed humans to  interrupt their natural hierarchy, also some animals are impossible to  domesticate (note the difference between feral, wild, tame and  domesticated). We also discuss several other topics like What 4 types of tissue are in the body?

•Origin of animals: Todays animals appeared during the Cambrian period  (540 million years ago), also known as the Cambrian explosion.

Mammals appeared during the Triassic period (250 Million years ago) Birds appeared during the Jurassic period (150 Million years ago)

Humans appeared during the tertiary period (65 million years ago) which was also viewed as the period of land bridges that linked north America to Asia.

Pig, cow and horse ancestors appeared about 53 million years ago.

Principles of Evolution: Evolution is the process by which changes occur over  SUCCESSIVE GENERATIONS; BOTH animals GENETICS and its ENVIRONMENT  are important for evolution. 

Biologist whom started to study evolution include, Charles Darwin, William  wells, Patrick Mathews and Alfred Wallace.

Animals will evolve as the inherently possess the ability to vary, reproduce in  excess, and are exposed to a continually changing environment.  

Darwin created the idea of natural selection, and that animals can gradually  change morphologically over time to adapt to their environment. 

Natural selection also works on existing genetics, and cannot introduce  variation.  

Natural selection is increased however, because animals in general have a  tendency to reproduce and overpopulate beyond environmental sustainability.

Adaptations are modifications that are maintained through natural selection.

Horses are a great example; they use to have feet, but slowly their feet  developed into hoofs

Evolution during domestication: during domestication an animal’s SOCIAL  environment is the primary force acting on existing variation.

Despite only aiming for social, some physical attributes still follow such as,  floppy ears, curled tails, white head spotting, this is due for selecting for a single  trait.  

The original trait being selected for was tameness and docility towards  humans, but it originated with natural selection. Artificial selection would play a  role later in the domestication factor.

Fox-farm experiments showed the effects of artificial selection, and how fast  artificial selection can take effect.

Domestication moves beyond taming: most animals are unable to be  domesticated; for example, Of the 148 hooved animal species, only 14 are  currently domesticated.  

Fish are still working on being domesticated, while some animals we keep as  pets are not considered domesticated such as snakes and other exotics.

According to DARWIN, domestication required breeding of animals in  captivity, was goal oriented, increased reproductive success of the animal, brought  about atrophy or reduction in organ systems, enabled greater demonstration of  adaptability, and was a process facilitated by subjugation to humans. 

Tame is the acceptance of humans for a brief period of time, and will not last  generations. It is only temporary. The offspring of tame animals will show  wild behaviors even if their parents do not. Genetically there are absence of  domestic markers.  

Feral animals are animals where were at one point domesticated but through  generations of not having human contact have started to go towards their wild  state.

Major species of domesticated individuals include cows, pigs, sheep, horses  and goats. Minor species include donkeys, water buffalo, reindeer, llama  alpaca, camels, and yaks.

Behaviors that support domestication are large social groups with a  hierarchal structure, promiscuous mating with male dominance, signal  reproductive readiness through postures, prosocial young, short flight distance  and low reactivity to humans, herbivores or omnivores, low stress response to  confinement. 

Domestication where and when?:Wolfs were one of the firsts animals to be  domesticates, estimated about 17-15 thousand years ago.

Domestication events tended to occur where food was more scarce, and  hunting was not always most optimal. 

In the tropics very few if no domestication events occurred because the  climate allows for hunting all year round, and animals didn’t have to connect with  humans.

Most of the evidence of domestication occurred towards Mesopotamia.  

Pigs have had the most domesticated events out of all the domesticated  animals.

The stages of domestication:

1. Control over animals in the wild

2. Control over captive wild animals

3. Breeding of captive animals

4. Morphological changes in captive animals

Welfare and behavior

Nutrition & the early years

 -first nutritional study evidence in the Book of Daniel (2500-2400 years ago)

-Hippocrates made the first references to the medicinal properties of food and that proper amounts of nourishment was key to be healthy

-origins of nutrition as a science began during the chemical revolution in the  late 1700’s

-Antoine Lavosier defined life as a chemical process

-1886 Francois Magendie discovered diversity was key to proper  nutrition by conducting experiments with dogs, and only feeding some one  nutrient category which passed away and others all the nutrient categories  which lived.  

- Weende identified food components in the 1860’s, also providing  approximant analysis of feed  

Nutrition: The sum of the processes in an animal by which feed (or food)  substances are consumed, metabolized, assimilated, and waste products  eliminated ULTIMATELY, Supports growth, tissue maintenance and repair, and  extension of products 

-Food is an item that supplied nutrients in its natural state

-feed is food that is supplied to an animal system (often processed)  

Nutrients: Any chemical element or compound in the diet that supports  maintenance of life processes and extension of growth, reproduction, and  lactation.

-also something that is required to support cellular needs and thereby  support work, maintenance and repair of tissues.

Nutrient classifications: Water, Protein (crude Protein), Carbohydrates, Lipids,  Vitamins, Minerals (ash) 

-vitamins were not originally a nutrient category, because they were  not discovered until 1880’s by Christian Eijkman.

-protein is based off the amount of nitrogen in the feed

-essential or indispensable nutrients are required I the animals diet,  because the body doesn’t make enough of it on its own 

- nonessential or dispensable nutrients are not required in the diet  

-water is the most over looked nutrient category, it makes up 50-75% of the  adult body and up to 90% of a newborns body, as well as 60-65% of the mass of a cell.

-as little as the loss of 10% of water can be deadly  

Water functions 

1. Required for reactions of the body

 2. Maintains constant body temperature

-universal solvent

-transport medium and a diluent and required for the transport of semisolid  digests in the gastrointestinal tract.

-transports blood, tissues, cells and exogenous secretions (urine and sweat) -used to keep the body cool by evaporation (sweating and panting)

Water loss from the body is constant, and animals must constantly consume  water in someway to remain hydrated, it could be via the food they consume  or drinking fluids directly.

-urination is the primary method of water loss

Nutrient functions: Structural components, Sources of energy, Regulatory  functions

Energy is a function of the carbon skeleton: Protein – 5.65 kcal/g;  Carbohydrates – 4.15 kcal/g; Lipids – 9.45 kcal/g


-primary source of energy, but not a required dietary essential. -Categorized as simple or complex

Simple carbs are referred to as sugars and are classified as monosaccharides  or disaccharides

Monosaccharides include glucose, galactose and fructose.  -glucose is the primary source of energy for most cells

Disaccharides include maltose, sucrose and lactose  

Complex carbs include the polysaccharides: starch and fiber.

Starch include polysaccharides like amylose which is a straight line of glucose and amylopectin which is branched.

Fiber include polysaccharides like cellulose, hemicellulose, pectin and lignin.

Metabolism: the process by which the body uses the nutrients to support the  needs of living systems  

Catabolism: the process of the body breaking down nutrients  Anabolism: the process of building new compounds 

Calorimetry: Measure of energy

1) calorie = amount of heat required to raise the temperature of one gram of  water from 14.5 to 15.5 °C

• 1000 cal = 1 kcal (Cal) = 4.184 kjoules

• Food labels

• Measure of potential energy!


1) Combustion of a sample results in energy manifested as heat

 2) A rise in water temperature reflects transfer of energy from the food to  heat

 3) A one-degree change in temperature of one gram of water equals one  calorie


Lipids as fatty acids are the most concentrated source of energy, source of  essential fatty acids, integral components of cell membranes and carriers of  the fat soluble vitamins.

95% of dietary lipids come from animal products, cereal grains and oils  supplied in the form of triglycerides

Triglyceride have three fatty acids attached to a glycerol back bone

Adipose tissue is a form of energy reserve, and the storage of lipids is  basically limitless unlike glucose.  

Most fatty acid chains from animals are strait, with even number of single  carbon bonds. this fat is saturated, so is solid at room temperature.

Unsaturated fat is liquid at room temperature, and have one or more double  bonds.

It can occur as cis or trans.

Most trans fats are manmade through hydrogenation and have been proven  to have negative effects on the body. Natural occurring trans fats have not  shown the same effect.

The difference between cis and trans fats are the placement of the hydrogen: in cis, the hydrogen is adjacent to the double bond are oriented in the same  direction, and in trans the hydrogens are adjacent to the double bond are  oriented in the opposite direction

*be sure to look at figure 4.1.11 to see the visual difference between  saturated, unsaturated and trans fatty acids*  

The most important unsaturated fatty acids for animals are linolenic acid,  linoleic acid

- Cats and other carnivores also require arachidonic acid - Ruminants have no defined dietary essential fatty acid requirements.

Phospholipids are another kind of fatty acid, but contain two fatty acid tails  and a phosphate group.


-product of gene transcription and are the molecules of enzyme-catalyzed  reactions, muscles contraction, metabolic regulation, and immune function,

All cells synthesize proteins  

Provide energy in time of need (only 4 Kcal/g when catabolized) Are made of amino acids

- Amino acids have a central carbon to s hydrogen, a carboxylic acid  group, amine group and a side chain (see figure 4.1.13)

- Peptide bonds hold them together, and multi peptides are called poly  peptides  

Primary structure of a protein is the linear sequence of the amino acids

Secondary structure is the result of local folding due to interactions between  closely located amino acids

Tertiary structures involve more distant interactions with polypeptide chains

Quaternary stricter results from the interactions between different peptides  chains

non-protein “amino” acids

Obligatory carnivores have an additional requirement for taurine Insects may have an additional requirement for carnitine

Vitamins: group of organic substances that are required in relatively small  amounts and are essential for life

1900’s is the start of the vitamin revolution.

Stephen Babcock is credited to discovering vitamin A, by doing studies with  cows

Fat Soluble Vitamin A Vitamin D Vitamin E Vitamin K 

Vitamin A can have a high toxicity, which is why we can’t eat polar bear livers Beta carotene can be used to fulfill vitamin A requirement in some animals

Vitamin D can be converted from sun’s radiation but should not be relied on  as the main supply of vitamin D

Water Soluble Ascorbic acid (vitamin c), Niacin, Biotin, Choline, Cobalamin,  Folic acid, Pantothenic acid, Pyridoxine, Riboflavin, thiamin 

Most animals make Vitamin C on their own. Guinea pigs, chickens, bats, and  humans do not make their own vitamin C  

Minerals: an inorganic solid crystalline chemical element that are required for  all animals.

Macro minerals are required in greater amounts and include calcium,  phosphorus, magnesium, potassium, sodium, chloride and sulfur 

Micro minerals or trace minerals are needed, but in lesser amounts. They  include numerous minerals, but some examples are chromium, cobalt,  copper, zinc, iron, etc.

Modern Cell Theory proposed by Schwann and Schleiden 

1. All living things are composed of cells 

2. The cell is the fundamental unit of structure and function in all living things 3. All cells come from pre-existing cells 

Robert Hooke discovered cells  

Deoxyribonucleic acid (DNA)  

Universal material of heredity

Three chemical components: 1) Phosphate. 2) deoxyribose (sugar backbone), 3) nitrogenous bases

Complementary base pairing

Chargaff’s rules: A: T and G:C


Genes Sequences of nucleotides that serve as

precursors to proteins Direct all processes of the cell – Blue Print of Life

Inheritance: Transfer of genetic material

Inheritance is the result of the mixing of blood, contributed by each parent of  the individual

Mendel’s observations

1. Many inherited characteristics (traits) are under the control of two distinct  factors (genes) – one coming from the male parent and the other from the  female parent

2. A trait may not show up in an individual, but be passed to the next  generation

Organization of a gene

Homologous Chromosomes Chromosomes coded

with “matching” information from the male and female

Locus Location of the gene Alleles Given copy of a gene Homozygous Gene  copies are the same Heterozygous Gene copies differ

Two Laws of Inheritance

Principles of Segregation only one randomly chosen allele is found within a  gamete  

Independent Assortment Separation of chromosomes (thus genes) is  independent

Absurd to real expression of traits:

Dominant allele (gene) “overpowers” and prevents expression of the gene at  the corresponding loci on the homologous chromosome

Recessive allele corresponding gene that is “masked” by the dominant allele  at the corresponding loci

Non-classical dominance

Co-dominance or No-dominance Neither allele masks the other and both are  expressed

Incomplete dominance or Partial dominance: An allele is expressed in a dose  dependent manner

Sex related inheritance

Sex linked Expression of a gene that is located on the X chromosome Sex limited Trait is limited to gender

Sex influenced Trait is influenced by gender, an allele that is dominant in one  sex is recessive in the other sex.

Some variation cannot be predicted

• Crossing-over

– Occurs during initial meiosis

• Mutation

– Insertion, deletion, substitution of nucleotide – New protein: Better  performance/Worse performance

Animal breeding-Applied genetics

Objective produce animals that excel for desired traits while  eliminating/minimizing occurrence of undesirable traits. Involves culling of  less desirable animals and selection of superior replacements.

Phenotype Observable measures of traits

qualitative traits

-Subjective measure

descriptive or categorical and classified into groups: red or black angus;  horned or polled sheep

Controlled by a few genes Progress of selection not difficult

Quantitative traits

Objectively (numerically) measured Milk production, loin eye area, weight,  speed

Polygenic Controlled by

many genes, often on different chromosomes, each contributing a small  effect

Tools for genetic change

Selection Obtaining a desirable

phenotype through choosing animals for mating

Mating Pairing of males and females

Phenotypic Selection


Climate Health Feeding Stress


Female parent Male parent Quantitative traits Greater environmental  influence, variable heritability

Qualitative traits Less environmental influence, greater heritability Predicting  genetic progress

Selection Differential Phenotypic advantage of chosen parents. Superiority of  selected animals compared to the herd average for a particular trait.

Heritability of the trait Proportion of phenotypic variation that can be passed  from parent to offspring

Generation interval Average time required to

replace one generation with the next. The shorter the generation interval the greater rate of change.

Genetic change per year

Heritability x Selection Differential Generation Interval  

Genomic based selection

Traditional animal breeding requires assigning a breeding value based on  desired production traits with expectation the traits are inherited within  offspring. MAS Marker assisted selection allows identification of regions of  DNA associated with a trait SNPS single nucleotide polymorphisms can be  identified in animals that are identified by key selection traits. The presence  of SNPs allows prediction of breeding value. Unlike MAS, SNPs scan the entire  genome not just predetermined regions.

Tools for genetic change

Selection Obtaining a desirable

phenotype through choosing animals for mating

Mating Pairing of males and females

Mating depends on desired results

Increased homozygosity Increase

predictability of progeny as future breeding animals by decreasing variation  of contrasting alleles (Aa)

Increased heterozygosity Increase

performance of progeny for production by increasing variation of contrasting  alleles (Aa). Can result in hybrid vigor (heterosis)

Outbreeding Mating of unrelated animals within lines & breeds or between  breeds. Increases variation, increases heterozygosity, increases productivity  through hybrid vigor. Greatest effects in lowly heritable traits and within the  first generation of crossbreeding.

Inbreeding Intensive breeding of close relatives practiced to maintain breed  standards and achieve predictability of offspring. Decreases variation,  increases homozygosity of desired and recessive gene

Molecular genetics

Transgenic organisms The purposeful

manipulation of an organism’s DNA for the

production of organisms with genomes that cannot be created through  traditional breeding

Basic history of reproduction:

-Aristotle had two theories:  

Preformation- the embryo was preformed and grew or enlarged during development Epigenesis- man arose from the successive differentiation of formless being Preformation would not be accepted until the beginning of the 20th century  1562- Fallopius discovered the oviducts (fallopian tubes in humans) 1573- the corpus luteum was discovered by Coiter

1672- the ovarian follicle was discovered by De Graadf

1677- sperm was discovered by Hamm and Leeuwenhoek

1825- the discovery that sperm fertilizes the oocytes  

1900- life originated from single cells by Driesh

1907- beginning of the study of artificial insemination (AI)  

1933- first book on AI published

1959- fist successful AI occurred in rabbits  

Female reproduction:

-ovaries are the primary reproductive organ in the female.

-female gametes are oocytes and are made in the ovaries  

- the ovaries also make the female sex hormones such as progesterone and  estrogen  

-the oviducts are a pair of convoluted tubes adjacent to the ovaries and extended to the uterus and are the site of fertilization as well as early cell divisions of the  embryo.

-the oviducts also help with the transport of sperm and the ova which move in  opposite direction towards each other.

-the oviduct has muscular tissue with contractile properties divided into three  sections:

-Infundibulum: adjacent to the ovaries; a lace-like structure envelopes the  ovaries and is responsible for capturing the release oocyte and  directing its transport  

-in the sow, cow and ewe the infundibulum is separate from the ovary,  but in the rat, mouse and hamster it forms a bursa that surrounds the ovary.

- in a mare, the infundibulum is attached to the ovary

-Ampulla: middle section, highly invaginated, which increase surface area and are covered with cilia to help move the oocyte down the ampulla

-ampillary-isthmic junction is where the ampulla and isthmic join and is the  site of fertilization  

-this site can delay the transport of the oocytes for several hours to  increase the chances of it becoming fertilized  

-once fertilized, the zygote will then undergo mitotic division while  traveling for 3-6 days through the oviducts to the uterus  

-Isthmus: final section of the oviduct.

-is similar to the ampillary, but has decreased surface area and the  cilia beat to transport oocytes and embryos to the utero-tubal junction,  where the isthmus connects to the uterus.

Uterus: has two uterine horns and/or a uterine body, which is made of three major  layers:

1. outer covering

2. myometrium- an intermediate smooth muscle layer responsible for uterine contractions

3. endometrium- mucosal lining of the uterus, site of embryo implantation or attachment  

Cervix: thick walled, protective cartilaginous, elongated barrier between the uterus  and vagina.  

-Is a smooth muscle sphincter that is almost always tightly closed except  during times of estrous and parturition

-cows, and ewes have transvers, interlocking ridges usually called annular  rings

-pigs deposit their semen in the cervix and the end of their ejaculate  administer a plug.

-main functions are to serve as a passage way for sperm, while filtering out  the weaker sperm and as a barrier to prevent bacteria from reaching the uterus  and a passage way for the fetus during parturition.

-the cervix produces mucous which has anti-bacterial properties, and  also forms a mucous plug during pregnancy  

Vagina: a tubular shaped organ of copulation, although it is very thin walled, very  elastic and the site of semen deposition for cattle, sheep, and horses.

Vulva: female external genitalia, often times swells during estrous.

Female reproduction in avian

-only the left ovary is functional, while fertilization occurs inside, growth and  development occurs outside.

-lack a corpus luteum, the yolk is what is ovulated (it’s the ovum).  

-the ovum is captured by the infundibulum (where fertilization occurs) and then  enders the oviduct.

- sperm can be viable for up to a week in the infundibulum, but the yolk only spends half an hour there, and fertilization occurs in half that time.

-oviduct is divided into different sections the first is the magnum, where it stays for  a few hours where the thick albumin forms  

-isthmus is after the magnum and two thin shell membranes form here

-uterus is after the isthmus (the egg is out of the oviduct) and is also called the shell gland, the egg can spend up to 20 hours here getting a hard outer shell and the rest of the albumin is added.

-notice there is no cervix present in the avian system

- in the vagina, the cuticle is added then goes out the cloaca

-about 30 minutes after an egg is laid another one is ovulated


Male reproduction:

Testes: make the male gametes (spermatozoa) and male reproductive hormones  such as androgens.

-continuously make gametes throughout the animals life once puberty  occurs.

- most are located outside the body, typically oval shaped, and include lobes  separated by connective tissue  

-suspended within the scrotum by the spermatic cord.

Seminiferous tubules: small convolutes tubules that are in the lobes stated above  and represent 90% of the mass of the testes  

-have germ cells like leydig cells and nurse cells

-leydig cells make testosterone and other androgens when stimulated  by luteinizing hormone

-nurse cells (sertoli cells) surround and nourish developing sperm and  mediating the effects of follicle stimulating hormone and  testosterone on the germ cells  

-also the site of spermatogenesis

Scrotum: tow-lobed sac that conforms to the shape and size of the testes and is  divided into two compartments by the scrotal septum

*the spermatic cord and the scrotum both physically support the testes and help  regulate the temperature by controlling how close the testes are to the body*

Wolffian Ducts

Epididymis: long, convoluted tube that functions to store, concentrate and transport sperm.

-conditions include a low ph and high co2 concentration

Transportation of sperm is affected by 3 factors:

1. pressure from the production of more sperm

2. external pressure created by normal movement  

3. negative pressure caused by ejaculation

- as the sperm passes through the epididymis it also gains mobility and  fertility, this is called maturation and takes about 10-15 days

- from the epididymis the sperm goes to the vasa differentia, which transport  the sperm to the urethra by smooth muscle contractions.

Accessory sex glands make the majority of the ejaculate and supply buffers,  nutrients, and inorganic ions to make sure the sperm is able to move and fertilize.

-ampullae are enlargements of the vas deferens located just before the  urethra and add fluid but are not present in all species including pigs

-vesicular glands are lobular and are located near the bladder. Also contribute to fluid volume, which contain fructose and sorbitol (sorbitol is only produced  here) to supply energy.

-prostate gland is located in different places depending on the species. It  supplies inorganic ions  

-cowper’s glad or bulbourethral glands produce different substances  depending on the species, in bulls it makes a substance that allows the bull to  flush out the female, in pigs it make a gel like pug to keep the semen in, and  prevent others from fertilizing her.

Penis: organ of copulation and depositing semen in the vagina or cervix, can be  vascular or fibroelatic  

-vascular: horses and humans have, penis enlarges via blood vessels filling  with blood creating an erection  

-fibroelatic: bulls, rams, and boars have, tissue is always firm when, the  sigmoid flexure straitens during an erection to lengthen the penis.  

Male reproduction in avian:

- simpler than mammalian males; consisting basically of two internal testes,  with an epididymis and vas deferens that lead to a rudimentary penis. - Rosters lack accessory sex glands, so the seaman volume is reduced - Turkeys must be artificially inseminated  


If only one testis descends, the animal is called an unilateral cryptorchid and  could be fertile.

If neither testis descend, the animal is most likely sterile and called bilateral  cryptorchid

This had a genetic link, so animals with this issues aren’t often mated, even  though the issue can be easily fixed through surgery  


The most common factor influencing puberty are age and weight. Nutrition can influence weigh

The presence of the opposite gender can influence puberty  

In females puberty is noted by the first sigh of estrous and ovulation, which  depends on the production of follicle stimulating hormone (FSH) and luteinizing  hormone (LH).

Look at figures 6.8, 6.9, and 6.10 for the estrous cycle and the hormone production  that goes along with it. 


Beguins at firtilazation, ad resuts in a ztgote, then turns into a morula, which  develops into a blastocyst.

The blastocyst becomes an embryo as it enters the uterus and continues to  develop into a fetus or the placenta.

In farm animals, the placenta does not allow the direct exchange of blood, so  no immunity is gained, thus the baby must drink colostrum right after birth  

In a diffuse placenta, sites of exchange are all over the placenta, this is in  pigs and horses

In a cotyledonary placenta, exchange takes place over select structures  called placentomes this is in cows and pigs  

In a zonary placenta there is a band attachment and dogs have this

In a discoidal pacent there is a disk shaped area for attachment and is  present in primates.

In zonary and discoidal, immunity is passed through the blood stream.

Prolactin is responsible for nesting behavior right before an animal gives  birth, and also stimulates milk synthesis.

Questions to consider:

Label the anatomy of the female and male reproductive tracts. What processes  occur with each associated structure?

How does the anatomy of the avian tract differ from that of placental mammals?  What processes occur throughout the avian tract to result in the production of a  fertilized egg in the absence of gestation.

Discuss the uterine physiology and the species differences in maternal-fetal  attachment?

Using the cows estrous cycle as a model, discuss the follicular and luteal phases,  the hormones present, and the processes that occur?

What is the relationship of estrogen and progesterone with the hypothalamus and  pituitary?

What is the relationship of FSH and LH on follicular development and corpus luteum  production?

How can we stop follicular atresia to increase ovulated follicles?

How can you synchronize estrus?

What role does the embryo play in the follicular/luteal phases of the estrus cycle?


Compare and contrast lactation of the monotreme, marsupial, and placental  animals.

Consider mammary gland structure, what are differences between cattle and pigs?

Trace the flow of milk from the site of synthesis to secretion from the mammary  gland. Focus on the processes that occur within the alveoli. What nutrients are  transferred directly from the blood and what nutrients are synthesized within the  secretory cells of the alveoli?

What supports the increased weight of the mammary during lactation?

Understand the cycles of lactation: 1) Mammogenesis and the relationship with  reproductive hormones 2) Lactogenesis and the relationship with hormones  (oxytocin, prolactin, epinephrine) a. What role does prolactin play in embryonic  diapause? 3) Galactopoesis 4) Involution a. What is the importance of the mammary returning to a nonlactating state

Key points from in class:

Purpose of Reproduction

Perpetuation of the species Reproduction is

nature’s 2nd strongest impulse

Provision of food Surplus of animals for food &

initiation of lactation

Genetic Improvement Only when offspring are

produced can impact of genetic improvement be realized

Success relies on coordination between endocrine system and reproductive  anatomy

Most economically important trait

Determines number of saleable and maintained animals and their products (milk,  eggs).

Female = default pathway

Spermatocytes to spermatids Developing sperm cells,

progressing through meiosis (phases I & II)

Interstitial cells or Leydig cells Testosterone producing cells Sertoli or nurse  cells Maintain testosterone enriched environment

Estrus Period of time when female is sexually receptive

to male. Due to increased concentrations of estrogen and signals approaching  ovulation (commonly referred

to as heat)

Estrous cycle Period of time from one estrus to the


Menstrual cycle Period from one menses to the next

Hormonal regulation of the estrous cycle

Follicular phase

Follicular development& increased estrogen

Luteal phase

Formation of corpus luteum and progesterone

Seasonal Reproduction

Short day breeders

Increased melatoninstimulates ovarian function

Long day breeders

Decreased melatoninstimulates ovarian function

Inverse relationshipbetween melatonin

and length of light

Melatonin maystimulate or inhibitpituitary hormonerelease

Monotremes Lay eggs after partial embryonic development Marsupials Give birth to  premature young and practice embryonic


Artificial insemination

Advantages of artificial insemination

maximize genetic improvement with greater access to superior genetics; control  over individual mattings; reduced mating costs; control of reproductive diseases

Disadvantages of artificial insemination

determining estrus of the female

Artificial insemination: A historical perspective

Species use of artificial insemination

Dairy cattle 70% of all cows Beef cattle 20% of all cows  

Pigs 90%, related to the size of the operation with greater

adoption in larger herds

Horses Depended on breed registration requirements Sheep Limited due to  procedure requirements Turkeys Extensive Broilers Not widely adopted except in  research and pedigree


Llamas & Alpacas Not widely used to techniques in semen

collection and preservation and conception rates

Semen may be used fresh or frozen and depends on the

qualities of the semen.

Estrous synchronization controlling estrous cycle so

females express estrus around same time

Reasons to use:

1. with AI - decrease expense of time & labor for detection of estrus 2. for success of embryo transfer


1. hormonal – induce ovulation to restart estrous cycle; or suppress ovulation 2. natural – weaning (sows & beef cattle)

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