mammary physiology quiz 3 Flashcards
subclinical mastitis symptoms
- milk udders appear normal
- milk contains high SCC
- infections are long, sometimes with bouts of clinical symptoms
clinical mastitis symptoms
- visual abnormalities in milk
- ## short term infections
Effects and treatment of gram negative bacteria
- LPS of cell wall is released along with endotoxins after bacterial death
- not treatable with antibiotics
- more of these cases become clinical
Effects and treatment of gram positive bacteria
- contain lipotechoic acid, typically are host adapted
- longer duration infections
- most remain in subclinical state
what two pathogens affect the milk, ducts, and parenchyma
strep spp. and S. aureus
what three pathogens affect the milk and ducts?
coryne, s. agalactiae, staph spp.
what pathogen affects the cow?
mycoplasma
what pathogen affects the milk, ducts and cow?
coliforms
what type of resistance occurs at a genus/species leve and involves the target organism lacking a binding site?
intrinsic resistance
what type of resistance involves a previously susceptible strain of bacteria that becomes resistant due to a mutation or DNA acquisition and causes the potential spread to humans?
acquired resistance
what are the three D’s to guide antibiotic therapy decisions
Detect (when was the cow infected?does this require immediate treatment?); Diagnose (is active bacteria still present?); Decision (will antibiotics help this cow?
inflammation persist in milk for ______ days with or without a biological cure
3-5
antibiotics are rarely useful for cows with previous diagnosis of _________, > or = 3 previous treatments for ____, >4 months of SCC> ________ cells/mL, and chronic clinical or subclinical mastitis in previous lactations
refractory pathogen; CM; 200,000
what are the 5 non-antibiotic treatment options?
- watchful waiting
- dry off affected gland
- divert cow to beef market
- segregate cow and use 1/4 milker
- early dry off of cow
Which of the following would most reduce persistency?
a. Fostering a newborn on another dam
b. Missing one milking in a dairy herd milked 3 times per day
c. Late pregnancy (7 months) in a dairy cow
d. Providing a dry or nonlactating period between lactations
e. All of the above would be equivalent
c. Late pregnancy (7 months) in a dairy cow
Increased frequency of milking or suckling
a. Reduces metabolic activity of mammary epithelial cells
b. Stimulates daily milk yield
c. Stimulates mammary epithelial cell loss
d. Stimulates the involutionary process
e. All of the above
b. Stimulates daily milk yield
Exogenous growth hormone would increase milk yield in cows only if
a. given during the first lactation of a dairy cow’s life
b. a dairy cow is in “positive energy balance”, or has sufficient nutrients available to support increased milk production
c. given during the first week of a cow’s lactation
d. it was given as an oral protein in her feed
b. a dairy cow is in “positive energy balance”, or has sufficient nutrients available to support increased milk production
Milk yield is equal in two cows through day 30 of lactation. Beginning on day 31, cow A is injected daily with a high dose of cortisol and cow B is not treated. One week later….
a. Compared to cow B, milk yield would decrease in cow A
b. Compared to cow B, milk yield would increase in cow A
c. Relative to cow B, milk yield would be unaffected in cow A
d. Relative to cow B, endogenous secretion of cortisol would most likely be decreased in cow A
e. More than one answer is correct
e. More than one answer is correct
Exogenous estrogen administration has been shown to
a. reduce milk yield in a variety of species
b. inhibit lactation by disrupting myoepithelial cell function
c. affect milk production regardless of whether progesterone is also administered
d. all of the above
d. all of the above
Proven strategies for evaluating milk yield in various species include
a. weigh-suckle-weigh
b. litter growth index
c. measurement of total RNA in mammary parenchyma
d. all of the above
d. all of the above