Animal Science- Test 3

What is Fescue Toxicosis (KY 31)?

Endophyte fungus produces ergot alkaloid toxins

What happens when broodmares eat too much Fescue?

Dystocia, prolonged gestation, enlarged foals, thickened placenta, and agalactia

What happens when cattle eat too much Fescue?

“Summer Slump,” Agalactia, thickened placenta, aborted fetuses, poor appetite

Exacerbated by fertilizing with high N; fat necrosis causes problems with digestion and calving

How to prevent Fescue Toxicosis

Pasture Management is the only option

* pull mares off 60 days before foaling; hay
* Test pasture for fungus; reseed
* Dilute by the planting of red/ white clovers, alfalfa
* Consider endophyte-free stains
* Keep pastures short to prevent seed heads
* Fertilization may make the problem worse

Factors that affect reproductive performance

Nutrition, Environment (temp, humidity, seasonality), Anatomical defects in the reproductive tract, Endocrine system imbalance, diseases

Over-condition

rarely observed, increased dystocia, you see them a lot in “hobby farmers” and show animals

“Flushing”

Increasing the level of nutrition (30 days before breeding)

Why is flushing done

Increases the rate of ovulation in the herd

Effective for heifers, ewes, and sometimes guilts

How often do producers want a cow to calve

every 12 months

Most cows probably won’t show estrus until after day 45 postpartum, therefore only ____ estrous cycles to get them bred (21 d)

2

A ___________ program is especially important for heifers calving for the first time

nutrition

Why do they need extra nutrients?

Will be lactating for the first time, still growing, uterine involution (preparation for another pregnancy)

Highest percentage in A.I. and why?

95% is turkey because they need a lot of muscling, 80-90% is dairy cattle because the bulls are mean

Advantages of A.I.?

Maximum use of genetically superior sire

* greater number of offspring
* facilitates progeny testing of young sire
* enhances genetic progress

Greater selection of affordable sires

Use deceased or dangerous sires

Aid in reduction of diseases

Improvement management

* improved her record
* improve uniformity of calf crop

Disadvantages of A.I.

Increased labor, management, and facilities

Accentuate poor genetics by using inferior sire

Future of A.I.

Brightened by the use of Lutalyse, Estrumate, and Synchromate-B for the synchronization of estrus

Future use would be increased if we could

* Successfully sex semen
* Breed lactational an-estrous cows

Semen Collection

Artificial vagina

* for bulls, stallions, and rams
* Not for boar (apply pressure by gloved hand)
* Used when mounting female or train to mount dummy

Electro-ejaculator

* Probe inserted into the rectum
* Electrical stimulation causes ejaculation

If collected too frequently, number of semen per ejaculate decreases

After collection, semen evaluated for:

volume, sperm concentration, motility of sperm, abnormalities of sperm

frozen semen lasts _____________

indefinitely

For maximum conception, the sperm and ova must be at the site of fertilization at the __________

peak of their fertility

Site of semen deposition

In uterus of cows and mares

* Deposition in uterine horn and has lower conception due to uterine trauma and possible infection

Superovulation

Hormone treatment of the female to induce multiple ovulations

* Uses: multiple births and embryo transfer

Embryo Transfer of Advantages

* Increased reproduction of valuable dams
* Decreased time of proof of dam through a greater number of progeny
* Extended reproductive life of injured or older dams
* Transport of exotic breeds or proven stock to restricted or underdeveloped areas

Embryo Transfer Disadvantages

* Costly…although it is decreasing
* ET offspring are not necessarily genetically superior
* Success rate is variable and not guaranteed

_______ hormone is commonly used to induce cattle

FSH

___________ are used to synchronize the estrous cycles of the donor cow and recipient cows

Prostaglandins

What are prostaglandins?

They resemble hormones in their actions, but are quite different chemically (produced by many tissues in the body)

Embryo Transfer Procedures

* Selection (transfer donor must be healthy, cyclic animals of superior genetic makeup)
* Synchronization (donor and recipient animals must be in the same stage of the estrous cycle)

___________ is the distinguishing feature of animals

Lactation

Mammary glands serve two functions ________ __and__ ____________

Provides nutrition and source of passive immunity to offspring

In the U.S. milk primarily comes from _____ __lesser extent__ _____ __and__ ________

cows

goats and sheep

What makes a mammal?

Most have hair, all have mammary glands (modified sweat gland)

Critical part of repro strategy in mammals

Lactation

Great variation in __________ glands among species

glands

How many glands and teats do cows have?

4 glands, terminate in 4 teats

How many glands and teats in the mare?

4 glands and 2 teats

How many glands in the sheep and goat?

2 glands and 2 teats

How many glands for multiparous animals?

6-20 glands in two rows along abdominal wall

A gland is __________

a secreting organ

A secretion may be _______,__ _______, or__ ________

poured out (secreted) onto the surface, poured into cavity, or taken into blood

Milk is synthesized and secreted from epithelial sells in a tissue consisting of ___________

alveoli

What is an exocrine gland?

Gland that secretes fluid into a duct

What is the endocrine gland

Ductless glands that secrete hormones into bloodstream, endocrinology

What are antimicrobial proteins in milk?

Lactoferrin (binds iron (Fe) required for bacterial growth), and Lysozyme (enzyme that hydrolyzes bacterial cell walls), Immunoglobulins (Ig)

What is the composition of milk? What makes up the most of it?

Water makes up the most of milk

Solids: Also contains lactose (1 glucose + 1 galactose), fat, protein, minerals, vitamins, other

How much of cows milk make up water and solids?

88% water and 12% of solids

The more fat in the milk, the more _______ the milk is

yellow

Time of sampling during milking

First-drawn milk (fore-milk) lower in fat and increases as milk is removed

“Fat leaves _________”

last

Fat % varies by __________

season

Higher in ________ __and__ __________

fall and winter

Lower in ___________ __and__ _____________

spring and summer

Temperatures >85

milk accentuated with high humidity

What are factors that affects milk production

Inheritance determines potential

* Low producers vs. high producers

Feed and management determine whether potential is reached

* Proper feed and care
* Production influenced by herd health

Male offspring cause ________ milk production

greater

* males are heavier and grow more quickly

Adjust production to the ________ of the calf

consumption

* continue milking the cow or put on another calf

Multiple births produce _________ milk than females with single births

more

Age of animal- max production at _____ yrs.

6

Younger and older females produce less milk vs. females that have had _________ lactations

several

__________ needs greater during lactation than gestation

nutritional

Inadequate _______ __or__ _________ forces cow to draw from her own body to sustain milk production

quality or quantity

Mastitis

Inflammation of the udder

Most costly disease of dairy cattle

What is mastitis caused by?

Usually caused by chronic infection of streptococcus and staphylococcus bacteria

What are the three main causes of mastitis?

Dirty or poorly adjusted milking equipment, poor milking practices (dirty animals), and injuries to cows because of their surroundings

Mastitis is recognized by ___________

milker

Detection or a symptom of mastitis is

clots or flakes in milk

What happens to the udder when the cow has mastitis

* quarter of udder is sensitive to touch
* she kicks a lot when touching there
* swollen or hot to touch

How to test for mastitis?

Tested for via California mastitis test

How to treat mastitis?

Treated by intramammary injection of antibiotics

* Antibiotics in milk are illegal; not destroyed by heat
* Observe withholding periods
* Dump it down the drain or use it to feed calves

How to avoid mastitis?

More frequent milking to reduction pathogen load and reduce growth medium (milk)

Prior to birth, fetus is in a ___________________ environment

sterile, protected, moist, and warm

At birth, fetus is exposed to ___________ environment

cold, dry

exposed to harmful organisms and predators

_______ is of paramount importance and why

Milk

* survival, development, and growth of young

Why is Colostrum important?

* Newborn has little or no immunity
* Transfer of immunoglobulins
* passive immunity transfer
* Protect from harmful microorganisms that cause illness
* Intestinal absorption of Ig lasts only 24 hours
* Intestinal wall of newborn permits antibody absorption
* Newborns must receive colostrum early
* The gut wall becomes less porous allowing little absorption
* Should have frozen colostrum on hand

Greater variation in milm composition occurs after ________

calving

Colostrum

Greatest variation in milk composition occurs after calving

Transition from producing colostrum to producing normal milk takes _____________

3-5 days

Milk not salable until the __________ milking

11th

Composition of Colustrum

Contains antibodies, Vitamin A and D, fat, protein, most minerals

Mammary gland that lactates ___________ is not genetically favorable

Continually

Glands develop and function in concert with the _______________ cycle

reproductive

Mammals reproduce ___________ times in their lives

multiple

Mammogenesis

structural development or growth of mammary gland

Lactogenesis

associated with the end of pregnancy and parturition; tissues changes from non-lactating to lactating state

Milk secretion

synthesis of milk by epithelial cells

Milk removal

passive removal from cisterns and ejection of milk from alveolar lumen

Lactation

milk secretion + milk removal

Galactopoesis

maintenance of lactation

Suspension

Maintain attachment to the body

Median Suspensory Ligament

Separates left and right halves of udder

Lateral suspensory ligament

outer wall of udder

Four Glands or Quarters

Separate from each other- milk cannot move between quarters

Teats are ____ inches long in cow

2-2.5

hollow tubes of skin, muscle and erectile tissue hanging from udder

Valve close top and bottom; sphincter muscle closes

Bottom opening = “streak canal”

What happens when cows are born with extra teats?

Removed less than 1 year old

Milk collecting system explain

Many collecting ducts (large and small)

Gland cistern and teat cistern

Alveolus

Sac-like structure with hollow center

Basic milk-producing structure in udder

Very small \~1 million/ cu. inch

Alveolus

Lumen lined with single layer of epithelial cells, what does the lumen do?

* Remove nutrients from the blood
* Transform nutrients into milk
* Discharge milk into the center of the alveolus

Epithelial cells are surrounded by contractile _____________ cells involved in milk ejection

myoepithelial

Innervation (neural system) inside udder is _______

sparse