Previous Quizzes Flashcards
True or False: Particular egg-laying animals, like monotremes, are considered mammals.
True
The ________ system of the mammary gland incorporates an ANASTOMOSIS, such that the mammary allows for the crossover of blood supply between udder halves; on the contrary, the _______system of the mammary gland DOES NOT incorporate this feature.
Venous
Arterial
In the mammary gland, the glandular or secreting tissue is known as ___________, and the connective tissue or support system is known as ____________
Parenchyma
Stroma
The primary support structure of the udder is the ____________ suspensory ligament, while the _________ suspensory ligaments and the ________ are minor support structures.
Median
Lateral
Skin
Which of the following allows blood flow by accommodating the increasing mass of the mammary as it fills with milk?
Sigmoid Flexure
Which of the following are part of the alveolus?
secretory epithelial cells
terminal duct
capillaries
myoepithelial cells
All of the above
What are two main defining characteristics present in ALL MAMMALS?
The two main defining characteristics present in all mammals are that they have hair and that they have a mammary gland that secretes a milk for the nourishment of neonates.
The mammary gland is independent of the abdominal cavity except for necessary supply and drainage systems. Name the feature in the mammary gland that allows for the passage of these supply and drainage systems. Name a specific structure that passes through this feature.
The inguinal canal allows for the passage of blood vessels, lymph vessels, and the nervous system into and out of the mammary gland.
Some specific answers include the external pudendal (pudic) artery, external pudendal (pudic) vein, mammary lymph vessels, as well as the afferent and efferent nerves.
How do Fursternburg’s rosette and the streak canal contribute to the prevention of mammary infection?
Furstenburg’s rosette provides a location for immune cells like lymphocytes to reside and monitor for pathogens and kill them. Furstenburg’s rosette can completely fold over the streak canal to further block entry by pathogens
The streak canal is lined with cells that secrete keratin, a bacteriocidal substance that blocks pathogen entry. It is a contracted stucture that makes it harder for pathogens to enter
How does the mammary gland differ structurally between primitive mammals and more higher mammals?
The mammary gland of primitive mammals is much more simple. Monotremes have a simple tubule lined with secretory epithelial cells that produce and secrete the milk onto the mammary hairs. There is no nipple in these animals. In Marsupials, the system is more complex and contains a nipple and many galactophores. Finally, in the placental mammals the mammary gland is a complex structure that contains many ducts, lobules and lobes. The alveoli are the structures responsible for secreting and synthesising the milk. These mammals also have nipples and they produce a milk that is fairly consistent in its components throughout lactation.
For every 400 units of blood, one unit of milk is synthesized. However, the total udder blood volume in the lactating cow is similar to a non-lactating cow. If total udder blood volume is similar in both lactating and non-lactating cows, then how does the cow produce so much milk during lactation?
Mammary blood flow and milk yield are positively correlated. During the first few days after calving, there is a 2 to 6 fold increase in blood flow to the mammary gland. Greater blood flow through the mammary gland increases the availability of nutrients. A considerable volume of blood is directed to the mammary gland during lactation to support milk synthesis. Blood flow is controlled by local and systemic regulators, such as oxygen, carbon dioxide, adenosine, lactic acids, pH, parathyroid hormone-related protein (PTHrP), serotonin, nitric oxide, and insulin-like growth factor 1 (IGF-1).
True or False: Lymph is a colorless fluid that circulates in the lymphatic system. This fluid maintains fluid balance in the body by carrying components like fats and glucose.
True
One of the functions of the lymph system is to protect the organism against infection. What are other functions that lymph has?
Prevent Tissue Edema
Detoxify Bacterial End Products
True or False: Lymph moves throughout vessels mainly due to differences in pressure and muscular contraction.
True
The _________ nervous system controls the mammary gland milk ejection
Sympathetic
The autonomic nervous system (i. e. epinephrine liberation from the adrenal gland) inhibits milk let down by:
Supression of myoepithelial cell contraction
Inhibition of blood flow to the mammary gland
Constriction of oxytocin release from the pituitary
True or False: The inguinal nerve is formed from the 3rd, 4th, and 5th lumbar nerves and provides sensory nerves to the udder skin and teats.
False
In ruminants like dairy cows, ______ is one primary energy source for _______ production through oxidative phosphorylation.
acetate
ATP
Where does all mammary lymph drain in the mammary gland before leaving the mammary gland? What is the function of this structure?
My answer: The mammary lymph drains to the supramammary lymph nodes in the mammary glands. This structure serves a major immune function as the plasma cells and lymphocytes, which are numerous in the lymph nodes, find and get rid of the foreign pathogens/antigens. Additionally, these lymph nodes detoxify bacterial end products.
Lymph drains to the supramammary lymph node before leaving the mammary gland via lymphatic vessels exiting through the inguinal canal. There are several possible functions to this structure and any two are correct. It performs a filtering function removing tissue debris or cell components including bacterial cell components. It houses lymphocytes that carry out part of these filtering functions. Lymphocytes can produce antibodies in the lymph nodes.
Pre-milking stimulus will alter the concentration of oxytocin in blood around the time of milking. Describe the differences in the oxytocin concentration curve between pre-milking stimulated cows versus no pre-milking stimulated cows. Describe the impact on milk flow rate during milking.
Before the milker is attached, pre-milking stimulated cows will have a slightly higher concentration of oxytocin than no pre-milking stimulated cows. This is due to udder prep (forestripping, dipping, wiping, etc). After the milker is attached, pre-milking stimulated cows will have a larger peak in oxytocin concentration that occurs earlier than no pre-milking stimulated cows, which allows for an increase in milk flow rate that also occurs earlier during milking. The oxytocin concentration in pre-milking stimulated cows will drop faster, resulting in a more rapid drop in the milk flow rate, allowing for the milking unit to be removed sooner than no pre-milking stimulated cows.
____________ gives rise to the functional portion of the mammary gland (parenchymal), and ______________ gives rise to the stromal tissue.
Ectoderm
Mesoderm
How many days after conception do the embryo’s mammary band and bud appear?
32 Days and 43 Days
In dairy heifers before puberty, locally produced hormones like _________________ and _________________ drive growth. After puberty, the primary hormones that cause mammary gland to grow are ____________ and __________________
1+2. Growth Hormone, ST, GH, bST, IGF1
3+4. Estrogen and Progesterone
Match the correct hormone with its location of secretion:
Progesterone
Estrogen
Follicle Stimulating Hormone
GnRH
Parathyroid Hormone
Progesterone = Ovaries
Estrogen = Ovaries
FSH = Anterior Pituitary
GnRH = Hypothalamus
PTH = Parathyroid Gland
True or False: Mammary gland estrogen and progesterone receptors are located in the membrane of the mammary epithelial cells.
False
During each recurring estrous cycle, the ____________ between estrogen and progesterone regulates mammary gland growth and development.
asynchrony
The decline of what hormone prior to parturition is sometimes referred to as the “lactogenic trigger”?
Progesterone
Match the correct hormone with its function:
Prolactin
Growth Hormone
Cortisol
Oxytocin
Prolactin = Stimulates milk synthesis and lactogenesis
Growth Hormone = Increases catabolism of fatty acids and glycogen
Cortisol = Release at parturition stimulates lactogenesis II
Oxytocin = Stimulates milk ejection
These are characteristics present in FULLY differentiated secretory mammary epithelial cells
Polarized and spherical nuclei
Extensive rough endoplasmic reticulum
Competent tight junctions
The use of bST _____________ SCC, and its effect is more evident in _____________ cows.
Does not change
Primiparous
Select all of the following hormones associated with maintenance of established lactation
Oxytocin
Prolactin
ACTH
Mammary epithelial cells perform multiple tasks to produce milk. The synthesis of elements like _____________ and ____________ and the transport regulation of non-manufactured milk components like ____________________and _______________ are primary examples of the extended functions carried out by the secretory mammary epithelial cells.
1+2. Enzymes, Proteins, Sugars, Lipids
3+4. Vitamins, Minerals, Ions, Water, Blood Proteins
The main sugar present in milk is __________, a disaccharide sugar formed by _________________and ________________. The synthesis of this disaccharide occurs in the ________________of the MEC.
Lactose
Glucose
Galactose
Golgi Apparatus
Some of mammary development involves ‘paracrine signaling’. What is paracrine signaling? Provide an example from bovine mammary development.
Paracrine signalling is when one cell secretes a signalling molecule, which acts directly on a neighboring cell without entering circulation. An example of this in mammary development is that the proliferating cells of the mammary epithelium are usually estrogen receptor negative, but the neighboring cells do have receptors for estrogen. Cells with estrogen receptors, when activated by estrogen, produce and secrete growth factors such as IGF-I. The growth factors enter the intersticial fluid and activate receptors on the neighboring cells which leads to the proliferation of the cell and isometric ductar growth.
Paracrine signaling occurs when one cells secretes a hormone or growth factor to a neighboring cell or cells that have the receptor and respond to the signal.
Estrogen works through this mechanism by stimulating the production of EGF and IGF-1 to drive growth in a neighboring cell. Likewise, progesterone uses this mechanism stimulating Wnt-4 production. Growth hormone also stimulates the production of IGF-1 by the fat pad to stimulate neighboring epithelial cells.
Define each stage and mention one defining process occurring during this phase:
Mammogenesis
Lactogenesis
Galactopoiesis
Mammogenesis is the development of mammary tissue - expansion of ducts and alveoli.
Lactogenesis is the functional differentiation of the mammary cells - increasing organelles, differentiation of the RER and golgi, formation of tight junctions, activation of milk protein gene transcription.
Galactopoiesis is copious milk production or enhancement of lactation. This the production of milk resulting from nutrient coordination and stimulation of abundant milk synthesis by the differentiated mammary epithelial cells.
How has selection for milk yield influenced circulating somatotropin concentrations in cows? Why?
Selection for milk yield has increased circulating somatotropin concentrations. Somatotropin is the main galactopoetic hormone. It is required for milk synthesis and by selecting for milk yield, we have selected for increased somatotropin secretion.
Milk from cows that are homozygous BB for the kappa casein gene will yield 4 to 7 percent more cheese. Which breed is associated with highest gene frequencies of the B kappa casein allele?
Jersey
Select all the compounds that can in some way be used as substrates for milk fat synthesis.
Free fatty acids from adipose
Acetate
Glycerol
Butyrate
Glucose
Low rumen pH alters the biohydrogenation of fatty acids resulting in altered fatty acid intermediates. Which of the following diet-related causes may result in low rumen pH?
Low fiber (ADF)
Feed is too fine
High carbohydrates (energy)
Low forage to concentrate ratio
Milk fat depression can be caused by a lack of roughage in the diet resulting in low rumen pH. Roughage causes chewing and saliva secretion. What buffer is contained in saliva that helps to stabilize rumen pH?
Sodium Bicarbonate
The biohydrogenation intermediates that maintain a normal rumen pH are what?
Cis-9, trans-11 CLA
Trans-11 18:1
In dairy cows, ___________ makes up 80% of milk protein, and ___________ makes up 20% of milk protein.
Casein
Whey
This milk enzyme can be used to measure adequate use of temperature and times used during pasteurization.
Phosphatase
True or False: Normal milk is low in Na and high in K
True
Match the milk component with its physical relationship in the aqueous portion of milk.
Lactose
Salts
Whey
Casein
Milkfat
Lactose - Non-ionic solution
Salts - Ionic Solution
Whey - Colloidal Solution
Casein - Colloidal Suspension
Milkfat - Emulsion
Milk proteins are synthesized using amino acids. Some are essential and some are non-essential. We are typically less concerned with non-essential amino acids. Why is this? What are potential sources of non-essential amino acids?
Non-essential amino acids can be synthesized in cells. Sources include glucose C from TCA cycle. Deamination and transmination are used to produce NEAA from ketoacids. Several amino acids are taken up in excess of use and used to produce other amino acids and others are taken up by the gland and don’t appear in milk protein - used to produce new amino acids.
Define the isoelectric point. What is milk’s value and why is it important?
IEP is the point at which proteins have neutrally charged - equal positive and negative. For milk, it is about 4.7 and when milk is at this point, the proteins precipitates or aggregates - the result is the consistency of yogurt.
What is rennet, what does it do, and why is it important?
Rennet is an enzyme. It cleaves the carbohydrate chains off kappa casein. Their removal results in the coagulation or aggregation of caseins - the result is formation of curd.
What is the impact of heating milk on milk quality and what happens?
Heating milk can cause denaturation of whey proteins and resulting in a cooked flavor due to sulfur amino acid exposure.
Heating milk at the correct time and temperature will kill some of the organisms in milk in a process called pasteurization. This decrease in the number of bacteria in milk improves milk quality by increasing the shelf-life of milk and providing a longer lasting product to the consumer that is less likely to contain pathogens. However excessive heating of milk causes the whey proteins to become denatured, or unfolded. The sulfur contained in the amino acids of beta-lactoglobulin was previously folded inside the protein and formed sulfide links. When the excessive heat causes unfolding of these whey proteins the sulfur is exposed and volatile sulfur compounds such as H2S form. These compounds give milk an undesirable cooked flavor and reduce the quality of milk.
What is the impact of lipase activity on milk quality? What are two sources of this enzyme?
Lipases cleave fatty acids from milk fat triglycerides with some causing a rancid taste. Bacteria and the cow are both sources of lipase enzyme activity in milk.
Match the appropriate PMO Requirements for Raw, Pasteurized, and Raw and Pasteurized milk
Bacterial limits of 100,000 CFU/ml
Bacterial limits of 20,000 CFU/ml
Somatic cell count 750,000 cells/ml
Negative test for drugs
Negative for phosphatase
Bacterial limits of 100,000 CFU/ml - Raw Milk
Bacterial limits of 20,000 CFU/ml - Pasteurized Milk
Somatic cell count 750,000 cells/ml - Raw Milk
Negative test for drugs - Raw and Pasteurized
Negative for phosphatase - Pasteurized
True or False: The primary purpose of UltraPasteurization is to extend the shelf-life of milk
True
What was the original purpose for pasteurization?
To destroy Tubercule bacillus - Mycobacterium tuberculosis
What is the relationship between pasteurization time and temperature?
Shorter Time requires higher temperature
Select the period(s) of time when cows are the most susceptible to mastitis infections.
Calving
Dry-Off
Which of the following are the categories of mastitis causing pathogens?
Environmental, Contagious, Opportunistic
__________ mastitis pathogens are transmitted during milking, whereas _________ mastitis pathogens are transmitted between milkings.
Contagious
Environmental
Antibiotics (antimicrobials) use different modes of action. Which modes of action are common to mastitis treatments?
Inhibition of cell wall synthesis
Inhibition of protein synthesis
__________ antibiotics prevent bacterial growth whereas __________ antibiotics kill bacteria.
Bacteriostatic
Bacteriocidal
Briefly describe the primary and secondary purposes of pasteurization
The primary purpose of pasteurization is to destroy all pathogenic bacteria.
The secondary purpose is to extend shelf life by reducing spoilage causing bacteria (and denature enzymes that affect milk quality).
What outcomes do farmers hope to gain by administering coliform vaccinations to cows?
Farmers hope to reduce the effect of toxins by administering coliform vaccinations to cows. Coliform mastitis is a response to the toxins generated by the coliforms during reproduction, not a response to the microbes themselves. Therefore the cow can generally clear a coliform infection herself. However, in some severe cases the infection becomes systemic which requires supportive care such as IVs. Through use of the vaccinations, farmers are hoping to decrease the effect of the toxins and reduce the number of cases that become systemic and require supportive care.
The goals are to:
-decrease severity of disease
-inhibit bacterial growth
-neutralize toxins
Staphylococcus aureus has a number of virulence factors. What are virulence factors? What do they do?
Virulence factors increase the ability of an organism to cause disease, multiply in the host, or evade the host’s immune response. They increase the survival of the pathogen and the severity of disease.
Virulence factors are components produced by some pathogenic bacteria that increase their ability to cause disease and evade the immune system. They may help with adherence to the host or other methods to help avoid immune cells. S. aureus has virulence factors such as adhesin, capsules, lipid A, and coagulase. Adhesin helps S. aureus adhere to the mammary epithelial cells, capsules are a slimey coating which help create a barrier between the bacteria and components of the immune system, Lipid A binds antigens the wrong way and coagulase breaks down fibrinogen.
What are the goals are trying to be achieved by using Dry Cow Therapy?
The goals that are trying to be achieved by using dry cow therapy are clearing up existing infections, which is done using intrammamary infusions. This goal, when achieved, will set the cow up to go into her new lactation with no lasting chronic infections. Another goal of using Dry Cow Therapy is to prevent any new infections at dry off and during the dry period. This is achieved through both the intrammammary infusion and either internal or external teat sealants.
One goal is to clear existing infections (subclinical).
Another goal is to prevent new infections during the dry period.
As the pulsation ratio ___________, the milk out rate increases, however, teats are more likely to become congested.
widens/increases
Which of the following moves milk from the claw to the receiver jar?
Gravity
Match the following system components with their definition.
Regulator
Pulsator
Bulk Tank
Milking Claw
Balance Tank
Vacuum Pumps
Regulator - Stabilize vacuum pressure by sensing pressure changes and admitting/restricting air into the system
Pulsator - Regulates milk/message phase of teat cup liner
Bulk Tank - A large storage for holding and cooling milk at a cold temperature until and can be picked up by a milk hauler
Milking Claw - Large resevoir, with narrow liners and alternating pulsation that moves the milk from the udder
Balance Tank - Provides momentary vacuum reserve, helps prevent vacuum fluctuation, and collects moisture and dirt to protect the vacuum pumps
Vacuum Pumps - removes air from the system
Which is the purpose of the acid rinse during a milking system cleaning cycle?
Inorganic mineral removal
Match the lab test with the bacteria it quantifies.
Standard Plate Count
PI Count
Lab Pasteurized Count
Standard Plate Count - Mesophilic Bacteria
PI Count - Psychrotrophic Bacteria
Lab Pasteurized Count - Thermoduric Bacteria
Which parlor type is typically only recommended for larger dairies (600 cows or more)?
Rotary
Which of the following parlor types is the most labor efficient for a conventional confinement dairy?
Parallel
How does a regulator control vacuum pressure in a milking system? If vacuum is too low, how does the regulator respond?
A regulator bleeds air or restricts air entry into the system. If vacuum is too low, then the regulator closes, restricting air entry and increasing vacuum pressure.
A regulator controls the vacuum pressure in a milking system through a pneumatic diaphram that can restrict or increase the amount of air that is allowed into the system. If the vacuum is too low (not strong enough) in the system, the diaphram will close/partially close to stop air from entering the system. The vacuum pump only removes air from the system so the vacuum will increase due to the restriction of air back into the system by the regulator.
How does the pressure in the pulsation chamber change when the milker is in the milk phase vs. the rest (or massage) phase? What causes the change in pressure.
The pulsator cycles the pressure in the pulsation chamber between vacuum and atmospheric pressure causing the inflation to open (vacuum) and close (atmospheric) to cycle between the milk (open) and rest (close) portions of the pulsation cycle.
How do air injectors aid in the cleaning of the milk line?
During cleaning, the milking system uses vacuum to clean. Injecting air during cleaning causes a wave or flooding action to cause cleaning solutions to reach the top of the milk line.
Provide three comparison/contrasts showing how parallel and herringbone parlors differ.
Parallel parlors and herringbone parlors differ in the position from which the cows are milked. In a herringbone parlor cows are milked from the side in front of one of the rear legs. In a parallel parlor cows are milked from directly behind them between their two rear legs.
These parlors also differ in the amount of size they require. The herringbone parlor requires approximately 2x as much parlor length compared to a parallel parlor for the same number of milking units.
These parlors are similar in the fact that they can both utilize rapid exit and indexing so that all cows move together and cows can be pushed back or allowed a bit extra space depending on their size or tendencies to creep forward. However, indexing is more of a necessity in parallel parlors.
Cow angle to the pit
Milking between rather than in front of rear leg
Safety concept of parallels
Reduces pit length per cow width
Steps of cows
Steps of parlor operators
Sequence gates in parallels
