Log in to StudySoup
Get Full Access to LSU - ANSC 1011 - Study Guide
Join StudySoup for FREE
Get Full Access to LSU - ANSC 1011 - Study Guide

Already have an account? Login here
Reset your password

LSU / Animal Science / ANSC 1011 / What are the 3 main parts of the male reproductive system?

What are the 3 main parts of the male reproductive system?

What are the 3 main parts of the male reproductive system?


School: Louisiana State University
Department: Animal Science
Course: Introduction to Animal Science
Professor: T. bidner
Term: Fall 2016
Tags: exam2studyguide, ANSC1011, ThomasBidner, and IntroductiontoAnimalSciences
Cost: 50
Name: ANSC 1011 Section 1 EXAM 2 STUDY GUIDE
Description: This study guide contains terms and main concepts on notes from male reproduction up until companion animal health and disease. Lecture notes. Email me at trahan1997@ymail.com for further questions.
Uploaded: 10/09/2016
24 Pages 158 Views 4 Unlocks

ANSC 1011 Kristy Trahan

What are the 3 main parts of the male reproductive system?


Most of the major terms and concepts will be on here.  

Male Reproductive System  

∙ Testis- hang in the scrotum; primary sexual organ 

o Hangs low for temperature control  

o Spermatogenesis can only occur here  

o Sperm and testosterone are made here  

o Makes sperm every day, whether they need it or not

o Technically, the bigger the better- produces more sperm  

o Testicular Parenchyma 

▪ Seminiferous tubules are stored here and make the sperm  

What is another name for the spermatic cord?

▪ Germ cells first go through meiosis and the last is mitosis, right before  connecting to the sperm  

▪ Sertoli cells (nurse cells) build the seminiferous tubules- are the  

equivalent of the follicular cell

∙ Surround the germ cell sand provide nourishment  

If you want to learn more check out Who are the achaeans in the odyssey?
Don't forget about the age old question of How is replacement cost calculated?

▪ Space between the seminiferous tubules are the interstitium  

Where is the sigmoid flexure?

∙ Contain capillary beds to vascularize the seminiferous tubules  

o Mediastinum- the big collecting duct for sperm in the middle of the testis  

∙ Spermatic Chord  

o Vascular, lymphatic, and nerves

ANSC 1011 Kristy Trahan

o Heat exchanger  

o Houses cremaster muscle  Don't forget about the age old question of 2. how did neo-assyrians maintain control over their empire?

o Pampiniform Plexus- combination of arteries and veins  

▪ Counter current exchange- arteries are completely encircled by the veins ▪ 39 C- 34 C: cools the blood going in the testis  

∙ Epididymis (in the scrotum with the testis)

o Sperm enter through one microscopic tubule into the head, to the body, and then  the tail of the epididymis  

▪ Epididymis gets larger towards the tail  

o IMPORTANT: when the sperm come out the tail, they have gained the ability to  become mobile and then mature

▪ Before, they are in a sort of suspended animation before becoming full  sperm (progressively motile- not quite fully motile)

▪ After reaching the tail, they are fully functional and this is where you  would collect sperm from if you were to use a needle and extract it  If you want to learn more check out How do vectors help replicate inserted dna?
We also discuss several other topics like What do you call an increase rate of chemical reactions without being consumed?

o Connects to the vas deferens, then goes to the ampulla

▪ Ampulla- holds a lot of sperm for storage and is an extension of the vas  deferens

∙ Sperm don’t mind body temperature- when they aren’t fully  

developed is when they are really affected  

o Goes through the inguinal canal- hole (literally a hole) through which the veins,  arteries, and spermatic chord go through  

∙ The ampulla then connects to the urethra

o Sphincters that control the bladder and ejaculation control one of the two  functions at a time

▪ You don’t want to get urine in the semen, which would kill the sperm  ▪ Close off to either the ampulla or bladder, depending on the action  We also discuss several other topics like Does patrol deter crime?

∙ Accessory Sex Glands: provide the medium to help push out the sperm when ejaculating

ANSC 1011 Kristy Trahan

o These fluids help make up semen  

o Seminal vesicles, prostate, and the bulbourethral gland (Cowper’s)

∙ Sigmoid Plexure

o Helps push the penis out when the animal gets an erection- doesn’t usually make  it bigger

o Stallions don’t have a sigmoid plexure- have erectile tissue (engorges full of  blood)

∙ Castration and Cryptorchidism

o Castration to remove the weak from the genetic pool, so they are easier to deal  with, and to remove the stink (musk smell)  

o Routine castration of males not used for breeding:  

▪ Lambs: 1-2 weeks old

▪ Boars: few weeks old

▪ Calves: 4-6 months old

▪ Colts: 1 year or later  

o Cryptorchid: crypt= hidden + orchid= testis

▪ May be mono (one) or bilateral (both)

▪ Testis in abdominal or inguinal cavity (requires major surgery)

∙ The testis down still is able to make sperm and the other does not,  

but both continue to produce testosterone

▪ Shows normal sexual behavior, bilateral is sterile

▪ Heritable

∙ Breed associations won’t let you register cryptorchid animals  

∙ Smaller animals tend to have a larger concentration of sperm in their semen  ∙ Bigger animals tend to give off a larger volume of sperm  

∙ The stallion makes a very viscous sperm (like runny jello) and the boar makes a kind of  clumpy fluid

∙ Semen collection and evaluation  

o Collection via artificial vagina (boars, rams, stallions)

o Collection via electro-ejaculation (bulls, rams)

▪ Device inserted into rectum and sends an electro current  

▪ Stimulates the reproductive parts right under the rectum  

∙ Ampulla, nerves, etc.  

o Collection vis gloved hand technique (boars)

o Evaluate for volume, concentration, % motile, morphology  

∙ Sperm  

o DNA is packed into the head  

∙ Pituitary gland produces LH and FSH (sertoli cells)- need this and testosterone for  spermatogenesis

ANSC 1011 Kristy Trahan


∙ Sets the production limits of a trait while the environment allows expression of the  genetic makeup: NATURE VS. NURTURE

o Genes and then the environment (the environment is very important



▪ Individual DNA makeup; codes for physical traits  

▪ Current branch of active research in animal science  

∙ Mapping, gene function, marker development (can do selection  

based on the different markers on chromosomes), and selection  


▪ How traits are inherited/passed to offspring  

▪ Manipulation in order to achieve increase in performance  

▪ GMO’s- genetically modified organisms


▪ Distribution and behavior of genes in various populations  

▪ Biological diversity- the more genetic variation, the better chances of  

survival (past and present)


▪ Statistical predictions of how all three of the previous branches can be  manipulated, and the possible outcomes

∙ Animal breeding has become more advanced than just animal  


∙ Mating decisions through arithmetic to make genetic improvement  

▪ Quantitative trait: anything that can be measured (height, weight, etc.) ∙ Animal Breeding: application of technologies and disciplines of genetics to improve the  selection of livestock for increased production

∙ Structure and Function of Genes  

o DNA is held together by hydrogen bonds in a double helix structure  

o Complementary base pairs: G-C, A-T

o DNA- deoxyribonucleic acid

▪ Forms the genetic code

o DNA nitrogenous bases

▪ Adenine (A) and Guanine (G)- purines  

▪ Cytosine (C) and Thymine (T)- pyrimidines  

o Simple Mendelian Inheritance  

▪ Only single pair of genes  

▪ Either expressed or not- dominant or recessive  

▪ Single strand of DNA, called a chromosome; smaller function unit called a  gene, CODES FOR PROTEINS

▪ Chromosomes usually occur in pairs- male and female parent  

o Chromosomes are homologous  

▪ Chromosomes will only bind with the same numbered chromosome (6  with 6, 7 with 7)

∙ Cattle: 30 pairs, dogs: 39 pairs, horses: 32 pairs

ANSC 1011 Kristy Trahan

o GENE: the basic physical unit of inheritance consisting of DNA sequence at a  specific location on a chromosome

o ALLELE: an even more basic unit of heredity

▪ Two alleles make up a gene (one inherited from the mother and one  inherited from the father in most animals)

o EXON: a segment of the gene that contains the “code” for the protein that should  be produced  

o INTRON: a large non-coding region of the gene  

▪ Possibly for the protection of coding regions during replication  

▪ A larger area for more advanced animals  

o Angus (black, BB) X Hereford (red, bb), offspring would all be black, since black  coat color is dominant (can also use a punnett square)

o Homozygote: pairing of like genes, BB or bb

o Heterozygote: pairing of unlike genes, Bb

∙ Principles of Heredity  

o Dominance- the interaction of alleles at a single locus, where heterozygotes  exhibit a phenotype more like the dominant homozygote offspring  

▪ Parents have genotypes of BB X bb for all offspring to have a black coat  color

o Recessive trait- when a phenotype can only be observed when an individual  inherits a recessive homozygous genotype (bb)

▪ Parents have genotypes of Bb X bb to get an offspring with red coat color o Punnett Square

▪ All dominant offspring since they all have a B in their genotype









▪ Some recessive (red coat colored) offspring  









▪ Exception:

∙ No-dominance- neither allele masks the other and both are  


o Example: roan color in shorthorns (red and white)

o RR- red, RW- roan, WW- white (none of these are  


∙ Genotype

o How determined? This is where the arithmetic is in genetics  

▪ Measure the phenotype under certain conditions  

▪ Phenotype= Genotype (g) + Environment (E)

∙ Phenotype

o A good measure of genetics but is not precise

ANSC 1011 Kristy Trahan

▪ May have a black coat color (dominant) but may either have a BB or Bb  genotype, which you can’t tell just by looking at the animal  

o Highly heritable traits: genotype and phenotype are very similar  

▪ Genetics are the main deciding factor  

o Lowly heritable traits: genotype and phenotype could be very different  ▪ Environment is the main deciding factor  

∙ Quantitative Trait: any trait that can be measured on a numerical scale (height, weight,  age, size, degree of infection, etc.)

o performance testing in animal production measures quantitative traits  

∙ Linkage: markers for a single trait or markers for multiple traits are inherited together  because of their proximity to one another on a single loci of a chromosome  o gene for milk production is also linked to fertility in dairy cattle, which is why  they have excellent milk production, but have fertility issues

∙ Pleiotropy: the phenomenon where a single gene is influencing multiple traits  o one gene can affect the traits of growth, milk production, and meat  

∙ Epistasis: when the effect of multiple genes is observed to affect the phenotype of a  single trait (ultimately makes things more complicated)

o Multiple genes may contribute or affect the growth trait

Animal Breeding  

∙ Animal breeding: application of all technologies and disciplines of genetics to improve  the selection of livestock for increased production

∙ Tools to make genetic improvements:

o Marker Assisted Selection (MAS) or Genomic Estimated Breeding Value  (GEBV)- genetics and statistics combined  

o Transgenic Animals- GMO’s  

▪ only been one animal that has been genetically modified and approved for  human consumption (salmon)

o Genomics- the whole genome selection (WGS)

▪ Study all the genes and try to figure out what they do

o Quantitative (statistics)- using arithmetic (widely used today)

∙ Heritability

o A measure of the amount of phenotypic variation that is due to additive gene  effects; the proportion of differences between individuals that is genetic


o Three classes of Heritability  

▪ Low 0-15%- reproductive traits  

∙ Fertility, litter size, twinning, age at puberty  

∙ The most important because WE SELL THE OFFSPRING  

∙ Lowly heritable, so the environment makes a huge difference  

▪ Moderate 20-40%- growth traits 

∙ Milk yield, feed efficiency, birth weight, weaning weight

∙ Single trait selection can make a lot more improvements more  

quickly (dairy cattle)- this hindered fertility abilities  

▪ High 45-60%- carcass traits 

∙ Muscle mass, fatness, mature size, cutability

ANSC 1011 Kristy Trahan

∙ Highly heritable, so the genes are the deciding factor  

∙ Selection Tools

o EPD’s (Expected Progeny Difference)- used for beef cattle and pigs  o PTA’s (Predicted Transmitting Ability)- used for dairy cattle  

o GEBV’s (Genetic Expected Breeding Value)- combination of single nucleotide  polymorphism (SNP) and phenotype/genotype of selected traits (EPD’s), used for  dairy cattle, few beef breeds (can DOUBLE genetic progress)

∙ EPD’s- selecting for the offspring  

o Expected Progeny Difference (statistical prediction)

o Based upon all records on an animal and relatives including offspring  ▪ Works well for pigs because they have so many offspring  

o Performance Information- records obtained for economic traits on traits that can  be measured

▪ Any data related to economics  

o EPD= a prediction of the progeny’s performance for economic traits ∙ Cattle EPD’s (4 main areas)

o Growth traits- weaning weight (different for dairy and beef cattle), yearling  weight, ADG (average daily gain)

o Maternal traits- milk EPD, birth weight

▪ birth weight is the only trait you don’t want a positive EPD for  

∙ The bigger the baby, the more birthing problems that could happen  ∙ Birth weight, weaning weight, and yearling weight are all directly  

connected, so if you choose for one, you choose for all

o Reproductive Fertility- scrotal circumference  

▪ the bigger the scrotum, the more sperm is produced  

o Carcass traits- carcass weight, marbling, rib eye area  

▪ Marbling- intramuscular fat

▪ The rib eye is related to the overall muscling of the animal  

∙ Swine EPD’s  

o STAGES- Swine Testing And Genetic Evaluation System  

o # born alive, 21-day weight (weaning)

o days to 250, back-fat thickness, lb. lean  

o Indexes:  

▪ SPI (Sow Productive Index)- measure of productivity based upon number  born alive and 21-day weight  

▪ MLI (Maternal Line Index)- used to select replacement females based  upon reproductive and post weaning weights  

▪ TSI (Terminal Sire Index)- used to select sires whose offspring will all go  to market  

▪ Days to 250, back-fat, and lb. lean  

∙ Money  

o Boars and rams: $500-10,000 or more, up to $500,000

o Yearling bull: $2,500-7,000

▪ Rule of thumb- commercial bull equals to 3 or 5 steers ($2,000 per steer) o Cattle semen-frozen called straws ($20-100)

ANSC 1011 Kristy Trahan

o Pig semen- mainly sold fresh, next day air delivery ($25-500 per dose, requires at  least 2 doses)

▪ Expensive because pig semen doesn’t do well frozen  

∙ Pigs Breeds

o Duroc- “Jersey red/red jersey”

▪ Medium cherry red  

▪ Ears point down  

▪ “They will grow on you”

▪ Origin: New York and New Jersey  

▪ Good carcass quality, rugged terminal sire

o Hampshire- “thin rind”

▪ Belted black and white, erect ears

▪ Origin: Hampshire, England

▪ Meat/terminal breed  

o Landrace  

▪ solid white, large ears pointing down

▪ extremely long-bodied  

▪ result of crossing the Large White from England and native hogs of  Denmark

▪ excels in maternal ability (maternal breed)

ANSC 1011 Kristy Trahan

o Yorkshire- “The mother breed”

▪ Solid white breed with erect ears  

▪ Originally called Large Whites  

▪ Origin: England  

▪ Maternal breed, currently dual purpose

Genetic Modification in Animals- Transgenic Animals

∙ “Traditional Transgenics”- insertion of recombinant DNA (a transgene) into the  genome of an animal  

o Germ line transmission  

o Random Insertion  

o Nuclear Injection (early stage embryos)

o Nuclear Transfer (cloning)- method of choice for larger/domesticated animals  ∙ Genomic Editing- molecular tools to make small changes “editing” in the genome at  precise locations  

∙ Transgenics is adding a transgene; editing is just making a small change in the genome  ∙ The Transgene  

o From a different source (organism)- it is a gene  

▪ DNA sequence that codes for a specific product- a protein  

▪ Regulator Sequence- controls expression when and where

∙ Promoter and/or enhancers  

∙ Expression in many tissues  

o Can mix and match the coding and promoters to get a  

desired result  

∙ Put together a transgene construct- recombinant DNA  

∙ Production of DNA

o Transgene inserted into plasmid (genetic component of bacteria)  

▪ Vector to insert DNA into bacteria

o Grown in bacteria, plasmid DNA isolated, then purified for injection/transfection

ANSC 1011 Kristy Trahan

∙ Characteristics of Transgenic Animals

o Low percentage of animals born are transgenic  

o Not all express the transgene- random positive effects

o Select founder animal(s)

▪ In most cases, a single animal is used to take transgenes from  

o Establish line usually from one animal  

o Transgenics in animals has taken longer because its more expensive than it  was for crops and plants

∙ Transgenics by Cloning (Dolly the sheep in 1996)

o Transfection of a transgene by electroporation  

▪ Millions of cultured cells

o Rare events selected for in culture

o Cloning captures altered genotype of cells as an animal with germ line  transmission of the transgene  

o Allows precise changes- gene targeting  

▪ Disrupts gene function, gene knockout (reduction/elimination of a  

function of a specific gene)

∙ Commercialization of Transgenic Animals  

o Transgenic salmon is the one transgenic animal approved for production and sale  as food

▪ Overexpression of growth hormone as a transgene  

▪ Transgene: codes for salmon GH- controlled promoter from antifreeze  protein gene of the arctic pout (eel-like fish that thrives in the cold)

▪ Transgenic salmon now produces GH all year from its own GH gene when  the water is warm  

∙ Salmon live in cold water for the most part and need warmer water  to grow- why they grow slowly  

▪ Grow twice as fast  

∙ Molecular Genome Editing

o Inducing precise changes in the genome such as deletions or exchanging  sequences without introducing a transgene 

o Three different tools to do molecular genome editing  

▪ Zinc Finger Nucleases (ZFN)

▪ Transcription Activator-like Effector Nucleases (TALENS)

ANSC 1011 Kristy Trahan

▪ Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) ∙ The nucleus is directed very specifically to a point in the genome

∙ Can result in insertion/deletion, which causes gene knockout

∙ Another result would be changing an amino acid, which could  

potentially bring several consequences

∙ Genomic Editing  

o Site directed editing  

▪ Deletions, gene disruption, knockout

▪ Sequence replacement, induce mutation, exchange alleles  

o Potential in animal breeding- alternative to marker selection  

o Horns in reproductive cattle breeds cause many problems and take a lot of time  and money to get rid of them

▪ Their genes haven’t been selected for no horns- have been selected more  for milk production and such  

▪ What they have done is gone into gene editing technology to insert a gene  for hornless cattle without losing all the previous gene advancements for  

milk and reproduction  

∙ Beef cattle took a very long time to get to where they are  


Animal Behavior  

∙ Ethology- the study of behaviors of animals in their natural surroundings  o Focuses on instinctive or innate behaviors  

∙ Applied Ethology- study of the behavior of domesticated animals  

o Directed at companion animals and livestock  

∙ Basic Principles of Animal Behavior  

o Results from changes in the internal and/or external environment  

▪ A barking dog (external stimulus) around a flock of sheep elicits behavior o Not all stimuli will elicit a response- meat around an herbivore  

o Behavior responses are not always predictable  

∙ Areas of Study-Communication- visual, auditory, tactile, and olfactory

ANSC 1011 Kristy Trahan

▪ Understanding communication of animals includes understanding signals  they give  

∙ Position of ears and tails

∙ General posture

∙ Hypervocalization

o Barking a lot? Hissing? Snorting?  

∙ Marking behavior

o Vision  

▪ Livestock have wide angle vision

∙ Cattle, pigs, sheep visual field of 300 degrees  

∙ Eyes positioned on the side of the head for maximum vision  

▪ Different species have different visual abilities and many have different  depth perceptions

∙ Important to understand an animal’s field of vision so you know  how to act around them (for each other’s safety)

∙ Making a loud noise or approaching an animal from their blind  spot may spook it and cause injuries (why you use your hand and  voice when moving around a horse)

o Auditory and Tactile  

▪ Most species have very good tactile sense- especially cows and horses ∙ Important to not surprise an animal with touch  

∙ Useful method to use when moving around an animal  

▪ Regularly communicate via several sensory systems with members of their  own species- vocalization and touch  

o Olfactory (sense of smell)

▪ Accessory olfactory organ- “VNO” or vomeronasal organ used to detect  odors called pheromones  

▪ Bulls and stallions use a flehmen response- curling of the lip and lifting its  head to smell urine from the female

ANSC 1011 Kristy Trahan

∙ Aggression and Social Structure  

o First studied in chickens

▪ “pecking order” from top animal to the bottom of the chain  

o Aggressive behaviors may revolve around survival needs:

▪ Obtaining food, reproductive needs, securing place in social structure o Problematic when humans and animals are forced to vie for dominance  ▪ If you can’t assert your dominance over a herd of animals, this could lead  to problems and injuries to yourself and others

o Aggression can also be a result of injury, pain, and fear

∙ Sexual and Maternal Behavior (important to understand)

o Sexual behaviors 

▪ Males will be very aggressive during breeding season or at breeding time ▪ Most farm animals will exhibit estrus or visible heat

∙ Red, enlarged vulva, vocalization, urinating in front of males,  

allowing others to mount, and mounting others

o Maternal behaviors 

▪ Some females will protect babies at all costs

▪ Can prohibit estrus behaviors from being detected

∙ Why some people have to the foal away from mares so they can  

get rebred  

∙ Companion Animal Behavior  

o Are still animals! - can be unpredictable outside of normal environment  o Further study of animal behavior can:  

▪ Improve diagnosis and treatment decisions  

▪ Identify animals in need of intensive treatment  

▪ Reduce euthanasia due to problem behaviors  

∙ Livestock Behavior  

o Understand why animals behave the way they do???? improve comfort and health of  animal in production setting  

▪ Solve practical problems of production  

▪ Facilitate handling and improve handler safety and animal welfare

∙ Flight Zone  

o Distance that an animal will free from an intruder  

▪ The animals’ safety zone

o Size of the flight zone determines how wild or tame the animal is

∙ Layout of Livestock Facilities

ANSC 1011 Kristy Trahan

o When working with animals, it is best to stay on the edge of the flight zone o Facility design can have a big influence on how the animals respond

▪ Dr. Temple Grandin  

o Cattle respond best to curved chutes with solid sides  

▪ Get less distracted and smaller chance of getting spooked if they can’t see  what’s outside the chute

∙ Also prevents animal from seeing what is at the end of the chute  

until they are almost there, so they always keep moving  

o Reduce the use of cattle prods- reduce stress to get the most product out of the  animal

∙ Animal Temperament  


o Temperament is the interaction of genetic effects and environmental factors ▪ Major component is fearfulness  

o One of the main factors that determine how animals react to handling

∙ Always have to be smarter than the animal to avoid unwanted abnormal behavior

Beef Cattle  

∙ Cattle comes from the word capital, meaning wealth or property  

∙ Christopher Columbus introduced cattle to the western hemisphere

∙ 1st Domestication

o The taurine- humpless, Bos taurus  

o Fertile Crescent- 7,000 years ago

∙ 2nd Domestication  

o The Zebu- humped cattle, Bos indicus  

o Indus Valley- 6,000 years ago (adapted to hot climates)

∙ Different Breeds  

o Bos taurus: English/British, Continental  

o Bos indicus: heat tolerant- need some of this for south Louisiana

o Composites: crosses the two  

▪ breeding a purebred Bos taurus and purebred Bos indicus results in hybrid  vigor- offspring will have more vigorous growth and characteristics  

∙ Historical Perspective  

o English settlers brought cattle to New England in 1609


∙ Three primary breeds imported to US

▪ Used as work animals and milk producers  

∙ ‘The Real McCoy’

o In the mid 1860’s Joseph McCoy bought 600 cows for $5,400 and sold them in  Abilene, KS for $16,800- was an entrepreneur  

o Between 1867 and 1881 McCoy sent more than 2 million cattle from Abilene to  Chicago- used the Chisholm Trail

ANSC 1011 Kristy Trahan

∙ Barbed Wire  

o Barbed wire was invented by J F Glidden in 1874  

o Cattle are now enclosed on ranches and no longer roamed the plains  ∙ ENGLISH BREEDS  

o The Angus  

▪ Origin is Scotland (British breed)  

▪ Black or red in color

▪ Most prominent beef cattle breed in US  

▪ Popular for carcass traits and maternal traits  

▪ Must be at least 51% black and exhibit “angus influence” to be considered  angus  

▪ In the top third of the USDA quality grade  

∙ Must grade prime or upper 2/3 of choice  

▪ Must meet all 10 criteria to labeled Certified Angus Beef

▪ Most cattle across the US are black 

o The Hereford  

▪ Origin is England (English breed)  

▪ Red with white face  

▪ Popular for their survivability and cross breeding (carcass traits)

∙ Predominant breed in the west because they didn’t produce a lot of  milk  

o It is hot out west and very dry  

o It takes more energy and nutrients to produce milk (harder  

to breed back in locations with limited resources like in the  


ANSC 1011 Kristy Trahan

o The Shorthorn  

▪ Origin is England (English breed)  

▪ Red, white, combination of red and white in color  

▪ Popular for their maternal (initially) and carcass (current)

∙ Historical Perspective  

o Cattle were originally raised and finished on grass until WWII came and a  demand for meat grew

o Mid 1940’s- major shift in the cattle industry

▪ Increase in surplus grain (demand for grain-fed beef grew)

o Surplus grain was fed to finish beef cattle- BIRTH OF THE FEEDLOT  INDUSTRY

▪ A new industry segment developed that involved concentrating large  numbers of cattle and feeding them grain in a FINISHING PHASE just  prior to slaughter  

∙ Ogallala Aquifer  

o Created by large lakes underground  

o From Nebraska to northern Texas  

▪ Drying out in northern Texas because they are using this water the most o The majority of beef cattle are located on this aquifer  

∙ Historical Perspective  

o Due to being fed grain, cattle were getting TOO FAT in the feedlot  o Small-statured animals with light adult weights produced calves that fattened well  on grass- calves fattened too well in the feedlot  

▪ led to the BREEDS REVOLUTION (1960’s)

▪ number of breeds in the US increased to over 70

▪ re-established crossbreeding and the production of new types of cattle  ∙ mostly continental breeds (Charolais)

ANSC 1011 Kristy Trahan

∙ Continental Breeds  

o Charolais  

▪ France is origin  

▪ Light tan to cream white in color  

▪ Popular for growth and carcass characteristics  

▪ The only time black color wasn’t the color of choice  

o Gelbvieh  

▪ Germany is origin  

▪ Golden to rust (black)  

▪ Popular for their growth and maternal traits  

o Limousin  

▪ France is origin  

▪ Various shades of red to black  

▪ Popular for carcass traits  

o Simmental  

▪ From Switzerland  

▪ Spotted tan to red and white; solid tan to red with white face; more  recently, black

▪ Popular for growth and maternal traits

ANSC 1011 Kristy Trahan

∙ Heat tolerant Breeds  

o Brahman  

▪ American Brahman mainly developed from three Indian Zebu breeds  ∙ Nelore ????

∙ Gir ????

∙ Guzerat ????

▪ US is origin (through the crossing of several breeds of Bos indicus cattle) ▪ Gray or red in color  

▪ Popular for their heat and insect tolerance; crossbreeding  

▪ Brahman influence in Louisiana: the further south in Louisiana you go, the  more Brahman influence you will see because of the hot climate

o Senepol  

▪ Origin is the Virgin Islands, St. Croix  

▪ Various shades of red  

▪ Popular for heat tolerance, early maturing, and survivability

ANSC 1011 Kristy Trahan

o Texas Longhorn (Spanish Longhorn)

▪ Origin is Spain/Mexico/US

▪ Multicolor patterns  

▪ Initially very popular for ruggedness (ability to survive in harsh conditions  and environments  

▪ Low birth weights

∙ Composite Breeds  

o A breed that is made up of at least two component breeds, designed to retain  heterosis in future generations without crossbreeding and maintained as a  purebred

o Common for composites to have 3/8 Bos indicus and 5/8 Bos taurus (for heat  tolerance)  

o Brangus (3/8 Brahman, 5/8 Angus)  

▪ origin is the Iberia Experiment Station in Louisiana

▪ black or red in color  

▪ popular for maternal and carcass traits; heat tolerance  

o Santa Gertrudis (3/8 Brahman, 5/8 Shorthorn)

▪ Origin is the US (King Ranch, TX)

▪ Color is red  

▪ Popular for heat tolerance, maternal and carcass traits

▪ Big growthy type cattle- grow faster than most other breeds

ANSC 1011 Kristy Trahan

o Braford (3/8 Brahman, 5/8 Hereford)

▪ Origin is the US  

▪ Red and white in color  

▪ Popular for their maternal traits and heat tolerance  

o Beefmaster (1/2 Brahman, ¼ Shorthorn, ¼ Hereford)

▪ The only exception to the 3/8 and 5/8 cross  

▪ Origin is the US  

▪ Multicolored (red, white, tan)

▪ Popular for maternal traits, heat tolerance, carcass

∙ Industry’s Purpose  

o Cattle utilize resources that cannot be utilized by humans- corn stalks/wheat straw ∙ Industry Today  

o Single largest money-generating commodity in all of agriculture o Beef production is widespread; we have efficient feedlots  

∙ Structure of the Beef Industry  

o Production System- starts with purebred operations  

o Purebred Operations

▪ Seedstock Producers- provide breeding stock to other seedstock producers  and cow-calf producers (elite purebred breeders)

∙ Mainly sell to other purebred breeders  

o Commercial Cow-calf Producers  

▪ 1st phase in producing beef  

▪ The end product is a 6-10 month old, 300-700 lb CALF usually sold at  weaning or to a feedlot to a stocker calf operator (sometimes ownership is  retained)

∙ Ownership is not usually retained because it’s expensive and very  

time consuming to raise a calf to productivity

ANSC 1011 Kristy Trahan

o Yearling (stocker operators)

▪ Purpose is to grow calves to heavier weights on low-priced forage (rye  grass)

▪ Sold to feedlot or retained  

o Feedlot phase (finishing)

▪ 600-850 lb cattle are finished to market weight and condition (1000-1800  lbs)

▪ Cattle typically spend 100-150 days or more in the feedlot  

▪ Last phase before slaughter

∙ Reproductive Management  

o Goal is to produce 1 calf for each cow every year  

o Gestation length: average 280-283 days

o Each cow must become pregnant within 80-85 days of calving  

▪ 283d+82d= 365d (100% calf crop)

o Cattle’s estrous cycle- 21 days

o Estrus (heat)- 13-17 hours

o Bred by artificial insemination (AI) or by a bull

o Proper estrus detection is essential  

▪ Check twice a day- AM and PM

▪ AM-PM rule for AI

∙ If in heat in the morning breed at night, if in heat at night breed in  

the morning

▪ Homosexual activity among cows (being mounted)  

▪ Heat checker bulls (sterile)  

∙ Heifer Reproductive Management  

o 1st calf heifer should 2 years of age (Bos taurus)  

o Breed at 15 months of age

▪ Should be 60-65% of mature body weight  

∙ Bull Reproductive Management  

o 15 months of age and older  

o Breeding Soundness Exam (BSE)  

▪ Testicular development, semen quality, ability to actually breed females  (libido)  

o The bull evaluation should be more important to the producer than selection for  replacement heifers- bulls are half the herd

Feedlot Industry  

∙ Feeder animal  

o Lambs, pigs, or calves of a weight and size that needs to be grown and fattened  before suited for slaughter  

▪ Calves are raised on grass before the feedlot, so they have to be switched  gradually to the feedlot grain diet  

∙ To avoid sickness and allow the rumen bacteria to adjust  

∙ Trends  

o 1950’s cattle and lambs were fed by Midwestern family farms  

o 1960’s and 70’s feeding industry shifted to high plains

ANSC 1011 Kristy Trahan

o 1980’s to present moved slightly north and east

▪ Because the Ogallala Aquifer is slowly drying up 

∙ Reasons for feedlot location  

o Available grain, dry climate, space (not in your backyard), feeder cattle source  ▪ People don’t want feedlots next to their homes because of the waste and  SMELL

∙ The whole beef cattle industry is based on the Ogallala Aquifer

∙ Feedlot Management  

o BIG BUSINESS- profit is the goal  

o Custom Feedlot- feed someone else’s animals (really selling feed)

▪ More of these now because they make more off of feeding someone else’s  animals- spreading out the risk  

▪ Want to do the best job possible and make a good profit off their animals  so people bring more animals next year  

o Commercial- feedlot owns the animals

o Risk is HIGH (why custom feedlots have become so popular):  

▪ 1. Fluctuation in cattle and feed prices  

▪ 2. Health Problems  

▪ 3. Storms- eat more before and less after  

▪ 5. Equipment and people problems

∙ Terms!!!!!!!!!!!!!!!!!!!!

o Pencil Shrink: an agreed upon adjustment to initial weight  

o Compensatory Gain: larger gain than normally expected due to thin/large framed  animals  

o Yardage Cost: non-feed cost per lb.

o Show List: potential buyers list of cattle ready for slaughter  

o Least cost ration: a livestock diet that is balanced for all ingredients but cost of  ingredients has been considered

o 4 step ration: four rations that are nutritionally balanced but energy is increased  for each diet from 1 to 4 and fiber is reduced (used to switch ruminants from  forage to high grain diet)

▪ Cattle are on grass before the feedlot and end up finishing with a 75%  grain diet  

∙ Do this gradually because you are feeding the bacteria and if done  

too quickly, can kill the bacteria (not good for the animal)

Companion Animals Health and Disease

∙ Veterinary Profession

o Governed by the AVMA (AVMA.org)  

▪ Accreditations, local and state chapters  

▪ American Veterinary Medical Association  

o Training  

▪ Education  

∙ Admission to veterinary school is very competitive!!!

o Grades, GRE, experience, extracurricular activities  

∙ Veterinary school is VERY expensive (approx. $12k per semester)

ANSC 1011 Kristy Trahan

▪ Continuing education  

∙ Need education hours every year after you get your veterinary  


∙ AVMA One Health Initiative  

o Human population continues to increase  

▪ People, animals, and our environment are becoming more  

interconnected and interdependent

∙ Contact between human and wild animal habitats increase  

o Increases risk of exposure to new viruses, bacteria, and  

other disease-causing pathogens  

∙ Companion Animals  

o Animal whose care and overall well-being falls under human responsibility  o Examples: birds, rabbits, horses, dogs, cats, etc.  

o 2/3 of American households have a pet  

o Benefits of pet ownership:  

▪ Pets can decrease your: blood pressure, cholesterol levels, triglyceride  levels, and feelings of loneliness

▪ Pets can increase your: opportunities for exercise and outdoor activities  and opportunities for socialization  

▪ “The healing power of the human-animal bond”


∙ Companion Animal Health  

o Wellness, preventative care is important!

▪ detect a problem early and there is less expense and difficulty  

∙ Better success rate, better for pet

∙ Preventative Medicine  

o Need to know/recognize animals  

▪ TPR (temperature, pulse, and respiratory rate)

▪ Body weight lb. to kg. conversion- divide by 2.2 to get kg

▪ Normal PE findings (physical exam)

∙ PE is the most important diagnostic tool!

▪ Bi-annual visits and exams- short life spans of dogs and cats  

▪ Spay/neuter- far too many animals in shelters  

▪ Parasite control/prevention/treatment  

∙ Parasite control begins at 2 weeks of age in dogs and cats  



∙ Neuter/ Population Control  

o Pet overpopulation a BIG problem in the US

▪ Approximately 3.7 million animals euthanized at shelters in the US per  year due to overcrowding  

o Spay and neuter at about 6 months of age in the clinic

o Spay- ovariohysterectomy  

▪ Benefits:  

∙ Greatly reduce the risk of mammary cancer if done young

ANSC 1011 Kristy Trahan

∙ Eliminate the chance of uterine infection  

o Neuter- castration

▪ Benefits:  

∙ Reduces chances of testicular cancer  

∙ Intact males get enlarged prostate over time  

∙ Medicine  

o Recognizing illness and disease can be difficult

▪ Instinct- try to mask signs of illness (don’t want to show weakness)

▪ Clinical Signs (not symptoms) rarely pathognomonic  

∙ Many presenting signs are non-specific (vomiting)  

∙ Don’t point to a specific problem  

▪ Rely on diagnostic tests, tools

Overall goal- QUALITY over QUANTITY of life

Page Expired
It looks like your free minutes have expired! Lucky for you we have all the content you need, just sign up here