ANSC 3040 FINAL QUESTIONS AND CORRECT ANSWERS
What is the close up period? (Cows) - Answers - last 3 weeks before calving
- moved to maternity pens
why do reproductive management strategies change according to categories? -
Answers - the reproductive scenarios are different to fit the needs of the animals
- heifers = still growing
lactating cow = in process of lactation
define puberty within dairy cows - Answers - first ovulation followed by a REGULAR
luteal phase
most important factor to puberty - Answers - body weight
- heavier = faster
why is over feeding an issue with dairy heifers? - Answers - Overfeeding can cause
accumulation of fat in the mammary glands
- causes less mammary tissue to be developed
- less functional tissue
Can have health issues
- mobilize fatty tissues after calving = predispose to metabolic and immune diseases
how can under feeding be an issue for dairy heifers? - Answers - reach puberty and
calve later = more costs
less milk during first lactation
higher risk for dystocia and limited capacity to compete for food among larger heifers
what 3 factors impact puberty age - Answers - genetics, breed and weight
when should dairy heifers reach puberty and when should they become pregnant and
calve? (ideal) - Answers - puberty = 9-10moa
pregnant = 13-15moa
calving = 22-24moa
why is having bulls present within a dairy farm for reproduction not recommended? -
Answers - 1. expensive - another mouth to feed
2. increased probability of accidents
,3. not able to select for genetic traits we want (can do with AI)
what are the 3 AI protocols for dairy cows? - Answers - 1. detection of spontaneous
estrus
2. detection of spontaneous and induced estrus (PGF2 alpha injections every 14d to
induce estrus)
3. times AI programs
most important estrus behavior - Answers - standing to be mounted
estrus characterizations (cow) - Answers - 1. vocalization
2. mucous vaginal discharge becomes clear
3. mounting attempts to other heifers
4. standing to be mounted
is it easier to detect estrus in dairy cows or other cows? - Answers - dairy cows - going
to the barn at least twice a day
- able to see more of them
- more chances of seeing expression of estrus behavior
how does tailk chalk work for estrus detection? - Answers - paint the back of a heifer
- if accepting to be mounted paint spreads
how do activity monitors work for estrus detection? - Answers - place on ankles when in
breeding pen
- constant measurement of activity which allows for tracking of activity to see for spikes
how do patches work for estrus detection? - Answers - normally start off silver (placed
on cows back)
- as they are mounted silver rubs off to expose color
- more color = likely estrus
what is the effect of body weight at the entrance in breeding pen to proportion of
pregnancy? - Answers - heavier weight = more likely to get pregnant
what is the purpose of using PGF2 alpha as an exogenous hormone? - Answers - acts
as the endogenous prostaglandin and induces luteolysis
- CL regresses
- promote decrease in progesterone production
met estrus = 4-5 days after estrus (CL still maturing)
- if given here, CL will not regress because still growing and too young
- ie. no response
, what is the purpose of giving exogenous GnRH? - Answers - release gonadotropins
- recruits a new follicular wave by causing small FSH surge
- induce ovulation by LH surge
what is an intravaginal device of progesterone used for? - Answers - release constant
concentrations of progesterone (normally kept in for 5-8 days)
- mucosa of vagina is good at absorbing levels of progesterone (need high levels for
longer to see effects)
- try to stimulate effect of a CL with high progesterone for longer time
injection would cause peak but then fall down (not good to induce fake CL)
what is the hormonal protocol for dairy heifers? (injections PGF2alpha) - Answers - two
injections of prostaglandins (14d apart)
- promote regression of CL = decrease in progesterone and allows follicle to finalize
growth and ovulate
- induce estrus
- within 3-5 days of injection = show estrus
second injection = safety mechanism for if estrus detection is not great
- causes luteolysis again on CL created by first injection
- allows for finalized growth of new follicle
- ovulation
- hopefully inseminate again
best response when done d6-17 in cycle
if the dairy heifer is in DI ESTRUS what does a hormonal protocol do? (PGF2alpha) -
Answers - has a CL which is responsive to prostaglandins
- when first injection given = promote regression of CL
- decrease progesterone and increase estrogen
- follicle finishes growing - could ovulate and show estrus
if the dairy heifer is in MET ESTRUS what does a hormonal protocol do? (PGF2alpha) -
Answers - CL not mature enough to respond to prostaglandins
- no response from CL
- selection of a new follicular wave but goes through atresia bc progesterone is too high
by the time we are at the second injection, animal is in di estrus - hopefully can cause
response as CL responsive
what are the benefits to a times AI? - Answers - 1. synchronize the follicular wave and
no longer need to detect estrus
2. by controlling the whole wave - can maximize the number of heifers inseminated
What is the close up period? (Cows) - Answers - last 3 weeks before calving
- moved to maternity pens
why do reproductive management strategies change according to categories? -
Answers - the reproductive scenarios are different to fit the needs of the animals
- heifers = still growing
lactating cow = in process of lactation
define puberty within dairy cows - Answers - first ovulation followed by a REGULAR
luteal phase
most important factor to puberty - Answers - body weight
- heavier = faster
why is over feeding an issue with dairy heifers? - Answers - Overfeeding can cause
accumulation of fat in the mammary glands
- causes less mammary tissue to be developed
- less functional tissue
Can have health issues
- mobilize fatty tissues after calving = predispose to metabolic and immune diseases
how can under feeding be an issue for dairy heifers? - Answers - reach puberty and
calve later = more costs
less milk during first lactation
higher risk for dystocia and limited capacity to compete for food among larger heifers
what 3 factors impact puberty age - Answers - genetics, breed and weight
when should dairy heifers reach puberty and when should they become pregnant and
calve? (ideal) - Answers - puberty = 9-10moa
pregnant = 13-15moa
calving = 22-24moa
why is having bulls present within a dairy farm for reproduction not recommended? -
Answers - 1. expensive - another mouth to feed
2. increased probability of accidents
,3. not able to select for genetic traits we want (can do with AI)
what are the 3 AI protocols for dairy cows? - Answers - 1. detection of spontaneous
estrus
2. detection of spontaneous and induced estrus (PGF2 alpha injections every 14d to
induce estrus)
3. times AI programs
most important estrus behavior - Answers - standing to be mounted
estrus characterizations (cow) - Answers - 1. vocalization
2. mucous vaginal discharge becomes clear
3. mounting attempts to other heifers
4. standing to be mounted
is it easier to detect estrus in dairy cows or other cows? - Answers - dairy cows - going
to the barn at least twice a day
- able to see more of them
- more chances of seeing expression of estrus behavior
how does tailk chalk work for estrus detection? - Answers - paint the back of a heifer
- if accepting to be mounted paint spreads
how do activity monitors work for estrus detection? - Answers - place on ankles when in
breeding pen
- constant measurement of activity which allows for tracking of activity to see for spikes
how do patches work for estrus detection? - Answers - normally start off silver (placed
on cows back)
- as they are mounted silver rubs off to expose color
- more color = likely estrus
what is the effect of body weight at the entrance in breeding pen to proportion of
pregnancy? - Answers - heavier weight = more likely to get pregnant
what is the purpose of using PGF2 alpha as an exogenous hormone? - Answers - acts
as the endogenous prostaglandin and induces luteolysis
- CL regresses
- promote decrease in progesterone production
met estrus = 4-5 days after estrus (CL still maturing)
- if given here, CL will not regress because still growing and too young
- ie. no response
, what is the purpose of giving exogenous GnRH? - Answers - release gonadotropins
- recruits a new follicular wave by causing small FSH surge
- induce ovulation by LH surge
what is an intravaginal device of progesterone used for? - Answers - release constant
concentrations of progesterone (normally kept in for 5-8 days)
- mucosa of vagina is good at absorbing levels of progesterone (need high levels for
longer to see effects)
- try to stimulate effect of a CL with high progesterone for longer time
injection would cause peak but then fall down (not good to induce fake CL)
what is the hormonal protocol for dairy heifers? (injections PGF2alpha) - Answers - two
injections of prostaglandins (14d apart)
- promote regression of CL = decrease in progesterone and allows follicle to finalize
growth and ovulate
- induce estrus
- within 3-5 days of injection = show estrus
second injection = safety mechanism for if estrus detection is not great
- causes luteolysis again on CL created by first injection
- allows for finalized growth of new follicle
- ovulation
- hopefully inseminate again
best response when done d6-17 in cycle
if the dairy heifer is in DI ESTRUS what does a hormonal protocol do? (PGF2alpha) -
Answers - has a CL which is responsive to prostaglandins
- when first injection given = promote regression of CL
- decrease progesterone and increase estrogen
- follicle finishes growing - could ovulate and show estrus
if the dairy heifer is in MET ESTRUS what does a hormonal protocol do? (PGF2alpha) -
Answers - CL not mature enough to respond to prostaglandins
- no response from CL
- selection of a new follicular wave but goes through atresia bc progesterone is too high
by the time we are at the second injection, animal is in di estrus - hopefully can cause
response as CL responsive
what are the benefits to a times AI? - Answers - 1. synchronize the follicular wave and
no longer need to detect estrus
2. by controlling the whole wave - can maximize the number of heifers inseminated
