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ANS 422: Beef Systems and Management > Reproduction > Flashcards

Reproduction Flashcards

1
Q

What is the primary reproduction goal for females?

A

Produce 1 calf every 365 days.

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2
Q

How is reproductive efficiency measured?

A

As # of calves born or weaned/100 females.

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3
Q

What is the avg. % calf crop?

A

91.7%

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4
Q

How much more important is reproduction economically than carcass or growth traits for producers selling weaned calves?

A

Twice.

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5
Q

What are the 4 reasons to have a controlled breeding season?

A
  1. Easier selection and culling.
  2. Easier care at calving time.
  3. Easier herd health management.
  4. Easier Cow nutrition management.
  5. Increased marketing options (more calves to sell at once).
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6
Q

What are the 3 reasons to not have a controlled breeding season?

A
  1. Cash flow is restricted to one part of the year instead of being able to sell calves throughout the year.
  2. If a mistake is made during a controlled breeding season, it is difficult to correct.
  3. In a controlled breeding season, the bull is used less during the year and you need to determine where you are going to put him when he is not with the cows.
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7
Q

How many operations practice controlled breeding seasons? Why?

A
  1. 41.3%.
  2. Most other operations are year-round due to tradition and weather.
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8
Q

How long is a short breeding season?

A

<60 days.

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9
Q

How long is a long breeding season?

A

> 60 days.

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10
Q

What is the average length of a breeding season?

A

86.7 days.

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11
Q

What are the steps in converting a controlled breeding season to a year-round operation?

A
  1. Determine when the last calf should be born.
  2. Remove bulls accordingly.
  3. Check for pregnancy 2 months after removing bull. Cull any open, dry cows or open cows with 5+ month old calves.
  4. Return bulls for gradually shortening breeding seasons (6 months, 4.5 months, 3 months).
    *Breed heifers one month before cows will be bred in year 3.
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12
Q

What % of operations raise their own replacement heifers?

A

83%.

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13
Q

What are the 4 goals for replacement heifers?

A
  1. Calve at 2 years of age.
  2. Calve early in the calving season.
  3. Deliver a live calf.
  4. Rebreed during a short season.
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14
Q

When are replacement heifers selected?

A

At weaning.

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15
Q

What are the 4 selection criteria for replacement heifers?

A
  1. Disposition.
  2. Frame score.
  3. Oldest and heaviest heifers (Born earliest and received plenty of nutrients.).
  4. Structural soundness (will their body last?).
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16
Q

How many replacement heifers should you select?

A

2x as many as you need.

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17
Q

What does an acceptable foot score (4-6) tend to be correlated with?

A
  1. A greater BCS at weaning.
  2. The weaning of a heavier calf.
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18
Q

When does puberty tend to occur in beef cattle?

A

12-13 months of age.
*Can be as early as 8 months of age, so separate them early.

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19
Q

Should you breed with the first estrus?

A

No, it is generally infertile.

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20
Q

At what weight should females be bred?

A

65% mature weight.

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21
Q

What are 3 reasons that some producers breed at 55% mature weight?

A
  1. Save on feed.
  2. Select for earlier maturing cows.
  3. Have early calving.
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22
Q

What weight should heifers be at calving?

A

85% of mature weight.

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23
Q

What 2 reasons should you avoid making heifers overly fat?

A
  1. Reduced lifetime milk production due to improper udder development.
  2. Increased calving difficulty due to narrowed birth canal.
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24
Q

Why should you avoid implants and growth stimulants?

A

They can inhibit uterine development.

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25
Q

What feed substance can reduce the age of puberty?

A

Ionophores.

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26
Q

What will feed restricting heifers result in?

A

A weak heifer and increased calving difficulty, not a smaller calf and decreased calving difficulty.

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27
Q

How is ADG calculated?

A

(Target wt.- Avg. weaning wt.)/# of days from weaning to breeding.

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28
Q

How many weeks before the cow herd is the heifer herd bred?

A

3-4 weeks.

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29
Q

How many heifers should you breed?

A

50% more than needed.

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30
Q

What kind of bulls are used to breed the heifer herd?

A

Low-birth weight bulls.

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31
Q

What should you do 60 days after breeding the heifers?

A

Pregnancy test, sell open and excess pregnant heifers.

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32
Q

How is pelvic area measured?

A

Pelvimeter.

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33
Q

What % of beef cows are bred by natural service?

A

95%.

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34
Q

For AI, do most producers perform live cover after?

A

Yes.

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35
Q

What is the signs that bulls have reached puberty?

A

They produce viable sperm for the first time.

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36
Q

When do bulls typically reach maturity?

A

9-12 months of age, sometimes as early as 8.

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37
Q

What is the scrotal circumference of a bull at puberty?

A

26 cm.

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38
Q

What breeds reach maturity earlier: smaller or larger breeds?

A

Smaller

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39
Q

What is the recommended bull to cow ratio for a yearling bull?

A

1:25.

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40
Q

What is the recommended bull to cow ratio for a yearling bull, natural service w/ estrous synchronization?

A

1:15.

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41
Q

What is the recommended bull to cow ratio for a clean-up following AI?

A

1:60.

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42
Q

What is the recommended bull to cow ratio for rugged terrain or low stocking rate?

A

1:35.

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43
Q

What is the recommended bull to cow ratio for a mature bull?

A

1:40.

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44
Q

What % of bulls are unable to achieve satisfactory conception rates?

A

20-40%.

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45
Q

What does a standard breeding soundness exam?

A
  1. Physical exam.
  2. Scrotal circumference.
  3. Semen evaluation.
    *May also include a venereal disease test and a libido test.
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46
Q

How does BCS affect breeding soundness exam?

A

A BCS below 4 or above 6 results in decrease in breeding soundness exam performance.

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47
Q

What 12 things are looked at during a physical exam?

A
  1. General characteristics.
  2. Body weight.
  3. Haircoat.
  4. Masculinity.
  5. Conformation.
  6. Movement and gait.
  7. ID.
  8. Eyes.
  9. Teeth.
  10. Feet.
  11. Legs.
  12. Temperament.
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48
Q

What 2 external reproductive organs are examined?

A
  1. Scrotum.
  2. Penis.
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49
Q

What are the risks with a pendulous penis?

A
  1. Stepping on it.
  2. Snakebite.
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50
Q

How do you properly measure scrotal circumference?

A

By grabbing above the testes, pushing the testes down and putting the scrotum circumference tape around the middle of the testes.

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51
Q

What is a semen evaluation done to measure?

A
  1. Spermatozoa Viability.
  2. Volume.
  3. Concentration.
  4. Motility.
  5. Morphology.
    *Varies by collection method.
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52
Q

How are semen samples collected?

A
  1. Artificial vagina.
  2. Surrogate stimulus animal.
  3. Manuel stimulation.
  4. Electroejaculation.
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53
Q

What is the average concentration of semen?

A

800 million-1.1billion/ml.

54
Q

What do venereal diseases causes in cows?

A

Abortions.

55
Q

What are the 3 venereal diseases of concern?

A
  1. Brucellosis.
  2. Campylobacterosis.
  3. Trichomoniasis.
56
Q

How is brucellosis detected?

A

Blood test.
*Only in Yellowstone.

57
Q

How is campylobacterosis detected?

A
  1. Sheath washing.
  2. Sheath scrapping and washing.
58
Q

How is trichomoniasis detected?

A
  1. Sheath washing.
  2. Sheath scrapping and washing.
59
Q

What are the 3 ways libido tested?

A
  1. Restrained heifer or cow (one or multiple services in 10-15 minutes).
  2. Restrain 4 heifers in a pen/multiple bulls introduced (3+ services in 40 minutes).
  3. Observe the bull during the first 5-7 days of the breeding season.
60
Q

When is a breeding soundness typically conducted?

A
  1. 2 months prior to breeding season.
  2. 1 week prior to breeding season.
61
Q

What are the 3 anatomical reasons for reproductive failure?

A
  1. Freemartin.
  2. Reproductive tract abnormalities (Ex: Blind Uterine Horn).
  3. Injuries.
62
Q

What are the 3 physiological reasons for reproductive failure?

A
  1. Anestrus.
  2. Cystic ovaries.
  3. Irregular estrous cycle.
63
Q

How does BCS impact calving?

A

The lower the BCS, the later the calving.

64
Q

What is BCS an estimate of?

A

Body fat stores on a scale of 1-9.

65
Q

What are the characteristics of a BCS 1?

A
  1. Emaciated-no palpable fat over spinous process, transverse processes, hip bones, or ribs.
  2. Prominent ribs and tail-head.
  3. Very weak.
66
Q

What are the characteristics of a BCS 2?

A
  1. Less prominent tailhead and ribs.
  2. Individual spinous processes still sharp but has some tissue cover.
67
Q

What are the characteristics of a BCS 3?

A
  1. Individually identifiable ribs, but not sharp.
  2. Obviously palpable fat along the spine and over the tail-head.
  3. Tissue cover over dorsal portion of the ribs.
68
Q

What are the characteristics of a BCS 4?

A
  1. Individual ribs are no longer obvious.
  2. Individual spinous processes can be identified by palpation. Feel round instead of sharp.
  3. Some fat cover over hip bones, ribs, and transverse processes.
69
Q

What are the characteristics of a BCS 5?

A
  1. Generally good overall appearance.
  2. Fat cover over ribs feels spongy.
  3. Palpable fat cover on either side of the tail head.
70
Q

What are the characteristics of a BCS 6?

A
  1. Firm pressure needed to feel spinous processes.
  2. A high degree of fat is palpable over ribs and around tail-head.
71
Q

What are the characteristics of a BCS 7?

A
  1. Fleshy and obviously carries considerable fat.
  2. Very spongy fat cover over ribs and around tail-head.
  3. Beginning of rounds or pones.
  4. Some fat around vulva and in crotch.
72
Q

What are the characteristics of a BCS 8?

A
  1. Very fleshy.
  2. Over-conditioned.
  3. Almost impossible to palpate spinous processes.
  4. Large fat deposits over ribs, above tail-head, and below vulva.
  5. Obvious rounds and pones.
73
Q

What are the characteristics of a BCS 9?

A
  1. Extremely wasty, patchy, looks blocky.
  2. Tail-head and hips buried in fatty tissue and rounds of fat are protruding.
  3. Bone structure no longer visible and barely palpable.
  4. Animal’s motility may even be impaired by large fatty deposits.
74
Q

How does BCS impact IgG concentration in colostrum?

A

As BCS increases, IgG increases.

75
Q

What are signs of estrus?

A
  1. Standing to be mounted.
  2. Restlessness.
  3. Roughed-up tail head.
  4. Being followed by a group of bull calves.
  5. Attempting to mount other cows.
  6. Pink swollen vulva.
  7. Clear mucous discharge.
76
Q

What is estrus detection necessary for?

A

Determination of timing insemination.

77
Q

What is the best estrus detector?

A

Bulls, preferably sterilized bulls if you are doing AI.

78
Q

When do cows ovulate?

A

24-30 hours after the onset of estrus.

79
Q

How long is the ova viable?

A

6-10 hours.

80
Q

How long is sperm viable in the female reproductive tract?

A

24-30 hours.

81
Q

How long odes sperm need to be in the female reproductive tract to be fully capacitated?

A

2-6 hours.

82
Q

Taking all of the timeline factors into account, when is the best time to inseminate?

A

6-8 hours prior to ovulation or 12 hours after estrus is detected.

83
Q

How can the sex of the embryo be controlled?

A

By examining the individual sperm to determine if they are carrying an X or Y chromosome and sorting them accordingly.

84
Q

Which sperm will have more DNA: An X-chromosome bearing sperm or a Y-Chromosome bearing sperm?

A

An X-chromosome bearing sperm.

85
Q

What are the 3 reason sexed semen is used?

A
  1. One sex of animal is more valuable than another in some cases.
    ex: Males for meat animals.
  2. Better economics by selecting female producing semen from a sire with strong maternal traits.
  3. Crossbreeding where having maternal sires produce only females and paternal sires only males would be the best use of resources.
86
Q

What is estrous synchronization?

A

The manipulation and control of the estrous cycle so the females in the herd enter estrus at the same time.

87
Q

What are 3 reasons estrous synchronization is used?

A
  1. To facilitate the use of AI.
  2. To facilitate embryo transfer.
  3. To increase the number of calves born early in the calving season (heavier calves at weaning and longer post-partum interval).
88
Q

What are the 4 brands of GnRH analogs?

A
  1. Cystorelin.
  2. Factrel.
  3. Fertagyl.
  4. Ovacyst.
89
Q

What are the 5 brands of prostaglandin analogs?

A
  1. Estrumate.
  2. In-Synch.
  3. Lutalyse.
  4. Prostamate.
  5. estroPLAN.
90
Q

What are the 2 brands of progestins analogs?

A
  1. Melengesterol acetate.
  2. CIDR (P4).
91
Q

What does the cost per pregnancy depend upon?

A
  1. Conception rate.
  2. The clean-up bull.
92
Q

What is embryo transfer?

A

The collection of embryos from donor females and transfer of them to recipient females.

93
Q

What process must the donor female undergo?

A

Superovulation.

94
Q

What is superovulation?

A

A hormone injection causing the development and release of more ova than normal.

95
Q

What are the 4 grades of embryos?

A
  1. Excellent or good.
  2. Fair.
  3. Poor.
  4. Dead or degenerating.
96
Q

What are the 9 stages of embryo development?

A
  1. 1-cell.
  2. 2-cell.
  3. 4-cell.
  4. 8-cell.
  5. 16-cell.
  6. Early morula.
  7. Morula.
  8. Early blastocyst.
  9. Blastocyst.
  10. Expanded blastocyst.
  11. Hatched blastocyst.
  12. Expanding hatched blastocyst.
97
Q

What is an advantage of embryo transfer?

A

Allows females to have many more offspring than normal.

98
Q

What are 3 problems with embryo transfer?

A
  1. Identifying candidates for ET is difficult due to limited data.
  2. Problems with genetic evaluation of individual’s performance, especially maternal traits, recipient usually not a high quality animal.
  3. More costly and difficult than AI, must synchronize donor and recipient if using a fresh embryo.
99
Q

What does pregnancy diagnosis allow for?

A

Allows for culling of open females and management of pregnant ones.

100
Q

What are the 3 methods of pregnancy diagnosis?

A
  1. Blood test.
  2. Rectal palpation.
  3. Ultrasound.
101
Q

What is the blood test looking for?

A

Pregnancy Specific Protein B.

102
Q

How many days post-breeding should heifers and cows undergo a blood test?

A

30 days.

103
Q

How many days post-calving should cows undergo a blood test?

A

90 days.

104
Q

What is the earliest a heifer/cow can be rectally palpated to check for pregnancy?

A

30 days gestation.
*45 days is most common.

105
Q

What is the earliest a heifer/cow can be ultrasounded to check for pregnancy?

A

21 days gestation.

106
Q

When can an embryo be sexed via ultrasound?

A

60-90 days gestation.

107
Q

Where does in vitro fertilization take place?

A

In a test tube using sperm and an oocyte from donor animals.

108
Q

What happens to eggs fertilized via IVF?

A

They are frozen or transferred to a recipient female.

109
Q

What are the advantages of IVF?

A
  1. Increased number of possible pregnancies (repeated collection of oocytes at short intervals).
  2. Decreased generational interval, due to eggs being collected from young, pre-pubertal females that are matured, fertilized, and transferred.
110
Q

What are 3 disadvantages of IVF?

A
  1. Expensive.
  2. Low success rate (~30% of embryos are transferable and ~50% pregnancy rate, so 10-15 of oocytes collected develop into calves).
  3. Abnormalities in offspring like large calf syndrome and higher incidence of male calves.
111
Q

What is cloning technology?

A

Technology for the production of genetically identical individuals.

112
Q

What is embryo splitting?

A

Cutting an embryo in half to produce twin embryos and transfer one or both to (a) recipient(s)

113
Q

What is the aim of embryo splitting?

A

To improve embryo transfer efficiency.

114
Q

How is cloning by nuclear transplantation accomplished?

A

The oocyte is matured in vitro and enucleated. The nucleus from the desired donor is implanted into the enucleated cell.

115
Q

What is a clone?

A

An exact genetic copy of an animal, usually an adult animal.

116
Q

What are the 3 benefits of cloning?

A
  1. Increased uniformity of performance.
  2. Allows for observation of variation due to the environment.
  3. Increased selection accuracy from the large amounts of performance data for each cloned line and increased selection intensity through unlimited access to the best cloned lines.
117
Q

What are 3 problems with cloning?

A
  1. If a small number of cloned lines is used, excessive inbreeding can easily occur.
  2. If a single cloned line comprises a significant portion of the population, there is a risk of increased susceptibility to environmental stress or a pathogen that causes widespread loss of production.
  3. Difficult, expensive, time-consuming.
118
Q

What are the steps of a 1-injection prostaglandin 10 day breeding program?

A
  1. Heat check and breed for 5 days.
  2. Give a prostaglandin injection to all non-bred cows.
  3. Heat check and bred for another 5 days.
    *Cheapest.
119
Q

How many cows are in heat per day?

A

5%.

120
Q

What are the steps of a 1-injection prostaglandin day injection after breeding breeding program?

A
  1. Give prostaglandin injection of day 0.
  2. Heat check and breed for next 4-5 days.
    *Only will synch 75% of cows.
121
Q

What are the steps of a 2-injection prostaglandin breeding program?

A
  1. Prostaglandin injection on day 0.
  2. Breed and heat check for next 4-5 days.
  3. Give prostaglandin injection on day 14.
  4. Breed and heat check for next 4-5 days.
    *To save money, only give 2nd injection to those that were not bred after the first injection.
122
Q

What are the steps of a Select Synch breeding program?

A
  1. GnRH injection on Day 0 to start new follicular wave.
  2. Prostaglandin injection on Day 7.
  3. Breed and heat check for next 5-6 days.
    *Tighter estrus synchronization.
123
Q

What are the steps of the Ov-Synch breeding program?

A
  1. GnRH injection on day 0.
  2. Prostaglandin injection on day 7.
  3. GnRH injection on day 9.
  4. Breed 24 hours later.
    or
  5. GnRH injection on Day 0.
  6. Prostaglandin injection on day 7.
  7. Heat check and breed those that are in heat.
  8. GnRH injection on day 9 to those to those that have not come into heat yet.
  9. Breed 24 hours later.
    *Even tighter than Select Synch. program.
124
Q

What are the steps of the Co-Synch breeding program?

A
  1. GnRH injection on day 0.
  2. Prostaglandin injection on day 7.
  3. GnRH injection on day 9.
  4. Breed on day 9.
    *Remove calves on day 9.
125
Q

What does prostaglandin causes the CL to do?

A

Regress.
*Recent cows are not cycling, so giving a prostaglandin may not always work.

126
Q

What are the steps of the MGA and Prostaglandin breeding program?

A
  1. Feed MGA (0.5 mg/head/day exactly) for 14 days. Do not breed on day 14.
  2. Prostaglandin injection on day 33.
  3. Breed and heat check for 4-5 days.
    *Developed for non-cycling animals.
127
Q

What are the steps of the MGA Select breeding program?

A
  1. Feed MGA (0.5 mg/head/day exactly) for 14 days. Do not breed on day 14.
  2. Prostaglandin injection on day 26.
  3. Prostaglandin injections on day 33.
  4. Breed and heat check for 4 days.
  5. Prostaglandin injections on day 37.
128
Q

What are the steps of the Co-Synch + CIDR breeding program?

A
  1. GnRH injection on day 0.
  2. Insert CIDR and leave in for 7 days.
  3. PGF2a injection on day 7.
  4. Pull CIDR out.
  5. Wait 2 days.
  6. GnRH injection on day 9.
  7. AI.
    *CIDRS will be releasing P4.
129
Q

Where is MGA commonly used?

A

The feedlot industry to prevent heifers from coming into estrus.

130
Q

What % of producers use AI in heifers?

A

15.1%.

131
Q

What % of producers use AI in cows?

A

5.5%.

132
Q

What stage of embryo development is used for embryo transfer?

A

Early blastocyst or Blastocyst.

ANS 422: Beef Systems and Management (3 decks)

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