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541 (sex class) > repro management beef > Flashcards

repro management beef Flashcards

1
Q

describe the bovine estrous cycle, including length and hormone involvement

A

whole cycle: ~21 days; ovulation = day 0

day 0 (ovulation) occurs at end of estrus and beginning of metaestrus

Metaestrus: ~5 days
- LH lowering
- FSH rises halfway through
- estrogen lowers
- progesterone starts low, increases

diestrus: ~13 days
- 2 LH peaks
- 3 FSH peaks
- progesterone peaks and then plateaus, then decreases at end of diestrus
- estrogen is low

proestrus: ~2 days
- estrogen increases, peaking at end of proestrus
- progesterone low
- LH increases, peaks at end of proestrus
- FSH lowers

estrus: ~1 day
- LH peak, then lower
- estrogen peak, then lower
- progesterone low
- FSH low

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2
Q

what are the two main goals of a cow-calf ranch?

A
  1. a cow to have her first calf at 2 years old
  2. every cow calve every year and raise that calf until weaning
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3
Q

tell me about the cow-calf cycle

A

breeding season (2-3 estrous cycles) –> weaning calves already had (6-7 months old) –> pregnancy (9 months) –> calving season (2-3 months) –> starts all over

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4
Q

where is the profitability in a cow-calf ranch?

A
  • calf crop: # weaned/#cows exposed to bull
  • avg weaning weight of calves (want calves to be born early in the calving season and want a uniform calf crop)
  • selling price of calves
  • annual cow cost (cost of production)
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5
Q

what are the constraints of the reproductive goals of a cow-calf ranch?

A
  • cow must calf every year to stay productive in the herd
  • gestation is fixed (280 days)
  • post calving anestrus/lactational anestrus/postparturiant interval
  • limited estrous cycles to get cows pregnant
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6
Q

to calve every 365 days, a cow only has ____ estrous cycle(s) to get preg

A

1!!!!!!!

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7
Q

for heifers, cows, pastured, and rangeland, what are the acceptable ranges and unacceptable ranges for confirmed pregnant?

A

acceptable, unacceptable

heifer: 95%, <90%
cow: 90%, <80%
pastured: 90-95%, <90%
rangeland: 80-90%, <80%

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8
Q

tell me about acceptable and unacceptable abortions per herd

A

A: 1-3
U: >3

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9
Q

tell me about the percent of cows calving (heifers and cows) that are acceptable and unacceptable.

A

acceptable, unacceptable

heifer: 94-98%, <94%
cow: 85-95%, <85%

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10
Q

tell me about % dystocia in cows and heifers that are acceptable and unacceptable

A

acceptable, unacceptable

heifer: <15%, >15%
cow: 2-5%, >5%

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11
Q

how can we achieve the goals of a cow-calf ranch?

A

calving season management:
- avoid wrecks and dz

breeding season management:
- heifer, cow, and bull mgmt
- season length/breeding

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12
Q

list 3 ways you can manage calving season

A
  • pre calving vaccines
  • minimize negative effects of dystocia on calf health
  • colostrum mgmt

basically you want to get healthy calves!

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13
Q

herds calving early had an _____ risk of calving assistance and stillbirths compared to late herds.

A

increased

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14
Q

early calving = _____ risk for pre-weaning mortality & preweaning treatment for disease

A

increased

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15
Q

tell me pros and cons for early calving (jan-feb)

A

pros:
- larger/older weaned calves = $$$

cons:
- coldest part of the year
- more feed required for dams
- more labor intensive
- worse for cows (increase stillbirths, calving assistance, pre-weaning mortality and dx tx)

purebred ranches and grain farmers tend to do this (grain farmers bc they want to be done with cows by the time grain comes)

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16
Q

tell me pros and cons for late calving (mar, apr, may)

A

pros:
- mod temp
- decreased feed/labor costs (usually larger pastures)

cons:
- spring storms = dz and death
- interferes with grain farming
- finished calves marketed during lower prices

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17
Q

tell me 3 areas in which we can control production parameters to meet cow-calf goals

A
  • bull selection/fertility status
  • cow processing
  • replacement heifer growth
18
Q

pre-breeding vaccinations should be given at least _____ before breeding for cows and bulls.

A

45 days before

19
Q

tell me 3 important things to do/check during the cow herd pre-breeding exam

A
  • vaccines (at least 45 days prior to breeding)
  • anthelmintic tx
  • body condition scoring
20
Q

what is the important pre-breeding cow vaccination to give? what type of vaccine is the best to use (killed/modified live)

A

MVL (protects against IBR, BVD type 1 and 2)

killed

21
Q

why is having a good BCS important for breeding?

A

gets them cycling sooner

22
Q

when selecting replacement heifers, when should you do a repro soundness exam and what are you examining?

A
  • evaluate 6 weeks prior to breeding (45 days)

looking at BCS, age, repro tract maturity

23
Q

what % growth do we want to see with heifers? important to know

A

65% mature weight at breeding
85% mature weight at calving

24
Q

when you select replacement heifers, you should choose ones that are born when in the calving season? why?

A

in the first 42 days

larger and reach puberty sooner

25
Q

breeding season for replacement heifers is when compared to cows?

A

30-42 days prior to cows

26
Q

first calf heifers calve when compared to cows?

A

0-20 days ahead of cows

27
Q

first calf heifers usually resume fertile cycles in _____ days

A

80-100 days

28
Q

cow lactational anestrus is about ____ days.

A

60

29
Q

we want a _____ pregnancy rate and a ____ calf crop.

A

95%, uniform

30
Q

why do we frontload calving season?

A
  • uniform calf crop
  • higher weaning weights
  • greater carcass weights, marbling scores, yield grades
  • late calving cows only get 1 estrus cycle before breeding season
31
Q

why do we do preg checks?

A
  • preg dx
  • marketing open cows
  • re-evaluate BCS
  • anthelmintics/vax/tx or cull for dz
32
Q

when should you conduct preg dx?

A

6-8 weeks after bull removal

33
Q

how do we do preg checks?

A

transrectal palp or US

34
Q

when is your greatest accuracy for preg checks?

A

35-65 days of gestation
- the earlier the preg check, the more accurate the gestation period

35
Q
  1. BCS of _____ is 2x as likely to be pregnant
  2. BCS <____ more likely to abort
  3. > ____ more likely to be pregnant
A
  1. 2.5/5
  2. 6/9
  3. 5/9
36
Q

describe a year of production on a cow-calf ranch.

A
  • pregnant from end of may to end of April
  • heifer calving Feb-Mar (20 days prior to start of cows)
  • cow calving Mar-Apr
  • May = pre-breeding vax + BCS
  • June = replacement heifer breeding (30-42 days prior to cows)
  • cow breeding szn Jul-Aug
  • preg checks 6-8 weeks after pull bulls = end of sept, early oct
37
Q

tell me the length of:
1. gestation of cows
2. breeding season for heifers
3. breeding season for cows’
4. heifer anestrus
5. cow anestrus

A
  1. 280 days
  2. 42-45 days
  3. 60-65 days
  4. 100 days
  5. 60 days
38
Q

what is the likelihood of a calf being born from a single mating?

A

60-70%

39
Q

when is the most embryo loss during gestation? what impact does this have on cow cycles?

A

by day 14, and then cow cycles again when expected

40
Q

after a cow gives birth, what happens to their first estrus?

A

delayed because of postpartum anestrus

I think this is only in beef cattle

41
Q

tell me approx % conception rate during each cycle of breeding (1, 2, 3, 4)

A

60-70% likelihood of calf being born from a single mating

1: 60%
2: 24% (60% of 60)
3: 10% (60% of 24)
4: 4% (60% of 10)

the math doesn’t really add up… but this is what it said in the lectures

42
Q

you have 3 herds that you’re analyzing. the y axis is herd conception rate and x-axis is period of time in days. for each herd, tell me if it’s normal or not, and if it’s abnormal, give me some reasons why.

A

Herd A: normal

Herd B: abnormal
- breeding season length too long/delayed conception
- cows have poor BCS = not cycling
- not having enough bulls
- bull fertility issues

Herd C: abnormal
- prolonged conceptions/cows have disease that is making them abort

541 (sex class) (22 decks)

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