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Botany > reproductive management of beef cows > Flashcards

reproductive management of beef cows Flashcards

1
Q

what do beef cows play an important role in

A

converting forage into high quality protein

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2
Q

what is key to the biological and economic sustainability

A

reproductive efficiency

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3
Q

what does achieving reproductive targets underpin

A

system efficiency and profitability

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4
Q

Key reproductive targets for beef cow
herds
Calving interval

A

365 days calving interval

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5
Q

what % of cows are cull annually as barren

A

<5%

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6
Q

what % of cows calving to wean a calf

A

> 95%

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7
Q

what % of cows should be calved in the first 42 days to have a compact calving

A

80%

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8
Q

what is the replacement rates for beef cow herds

A

16-18%

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9
Q

what age are heifers when they first calve

A

24 months old

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10
Q

what is the target calving interval
but
what is irish herds calving interval and how much does this cost

A

target: 365 days
irish herds: 403 days
costs €2.20/cow/day

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11
Q

what is the target calves/cow/yr
but
what is irish herds calves/cow/yr and how much does this cos

A

target: 1.0
irish herds: 0.8
cost: €170/cow

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12
Q

what is the target age of calving
but
what is irish herds age of calving and how much does this cos

A

target: 24 motnhs
irish herds: 15% of heifers 32.5 months
cost:€1.65/heifers/day

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13
Q

what is the national replacement rate% compared to the research %

A

national 14%
research 16%

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14
Q

what is the national calving rate% compared to the research %

A

national: 81%
research: 95%

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15
Q

what are the main factors of inefficiency

A
  • prolonged calving season
  • uneven calf crop
  • low use of AI
  • no defined planto produce replacement heifers
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16
Q

what are the two strategies to improve cost efficiency

A
  1. increase output to dilute cow costs
  2. reduce costs incurred by the suckler cow
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17
Q

how do you increase output to dilute cow costs

A
  • optimal herd fertility targeted
  • calf growth rates
  • high calf quality are the principal factors of importance
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18
Q

what is the profitability on irish suckler farms driven by

A

striking the correct balance between
maximising the output per cow while at the same time controlling costs per cow

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19
Q

factors impacting reproductive performances of a suckler cow diagram

A

slide 9

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20
Q

factors affecting reproductive efficiency (3)

A
  • age at puberty
  • post partum interval
  • conception rate
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21
Q

how much does ICBF indicate that each day is worth

A

€2.20

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22
Q

Two main factors that affect the post partum anoestrus interval
are:

A
  1. Maternal offspring bonding
  2. Nutrition (body condition score and plane of nutrition)
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23
Q

how many days / cycles have you to get a cow back in calf

A

50 days
2-3 cycles

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24
Q

how long is gestation

A

288 days

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25
Q

what does PPI stand for

A

post partum interval

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26
Q

what is the PPI of a dairy cow

A

mean = 26 days
(15-50 days)

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27
Q

what is the PPI of beef cows

A

mean = 55 days
(25-180 days)

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28
Q

are beef cows slow/.fast to come in heat after calving

A

slow

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29
Q

beef cows oestrous cycle

A

average 60 days
range 20-120 days

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30
Q

length of dairy cows oestrus cycle

A

average 30 days
range 20-50 days

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31
Q

how long is post partum anoestrus

A

14-170 days

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32
Q

Ovulation or (ii) Atresia of 1st Post-Partum DF diagrams

A

slide 16

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33
Q

postpartum cyclicity in suckled cows

A

slide 17

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34
Q

by what day does one large follicle develop in all cows

A

6-8 days postpartum.

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35
Q

how many outcomes has the follicle affecting days to 1st ovulation

A

3 outcome

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36
Q

what are the 3 possible outcomes

A

Incidence Days of ovulation
ovulation 5% 20
regression 93% 65
cystic 2% 60
Average 55-60

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37
Q

interval between first and second ovulation in beef cows
short (<18 days)

A

short (<18 days) - 85%

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38
Q

interval between first and second ovulation in beef cows
normal (18-24 days)

A

normal (18-24 days) 13%

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39
Q

interval between first and second ovulation in beef cows
extended (<24 days)

A

extended (<24 days) - 2%

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40
Q

what is anoestrus

A

Due to Failure of Recurrent
Dominant Follicles to Ovulate

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41
Q

POSTPARTUM ANOESTRUS IN
BEEF COWS

A

Not due to delayed resumption or lack of follicle growth

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42
Q

As a consequence of

A

Sequestration of LH stores in the gonadotrophs in the anterior pituitary due to inadequate pulses of GnRH

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43
Q

Factors affecting the PPI

A
  • Maternal-Offspring Bonding
    –> number one factor that affects the length pf PPI
    -Nutrition
    –>Pre-partum - more important
    –>Post-partum
  • Parity
    -Season
  • Bull effect
    -Interactions
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44
Q

Effect of Suckling Treatment on PPI
(Days)
free access:
restricted:

A

free access: 62 days
restricted: 42 days

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45
Q

LH pulsatility during the oestrous cycle

A
  • the oestrus cycle of a cows
  • luteal - high progesterone levels after ovulation
  • early follicular phase
  • Don’t have sufficient LH pulse – 1 LH pulse per hour is what is needed to ovulate
  • If u have a mature follicle and have a sufficient LH pulses to ovulate.
  • Late follicular phase spike – LH spike and with that you get estradial spike as well.
46
Q

Explain parity - the fact affecting PPI

A

o Heifers have much longer PPI than that of cows as they have a much larger energy requirement to meet their growth rate
o First energy sink of an animal
- Maintenance 60-65%
- Production
* Dairy cow: milk
- Growth - heifer has greater growth potential than a cow but DM intake is less
- Reproduction
* Resumption of cyclicity
* Heifer as to be managed differently than cows
- Heifer takes 15-16 days longer to come into heat

47
Q

what affect does the bull effect have on PPI

A

o Present of bull/teaser can bring them forward by 10-12 days

48
Q

Serum LH at 29 and 34 days postpartum in
beef cows

A
  • 34 days is extremely early
  • Restricted adjacent
  • Restrict isolation
49
Q

on what day does breaking maternal off spring bonding commence

A

Commence calf separation at Day 30

50
Q

what % of cows ovulate by day 36 and what sort of a ovulation is it

A

85-90% of cows ovulate by day 36

it is a silent ovulation

51
Q

what % and with how many days do cows exhibit fertile heat

A

95% of ovulated cows exhibit fertile heat with 8-12 day (short cycle)

52
Q

what% of cows exhibit fertile oestrus within how many days??

A

5% of ovulated cows exhibit fertile oestrus within 17-22 days
(normal cycle)

53
Q

what % of cows fail to ovulate in response to calf separation

A

10-15%
Deep – “Nutritional” anoestrus
- Thin cows at calving in particular
- No matter what you do you are going to have a delayed PPI

53
Q

what % of cows exhibited fertile heat by Day __

A

80% of cows exhibited fertile heat by Day 45.

54
Q

what does body condition score describes

A

fat reserves

55
Q

what point scale does UK and USA use

A

5 point scale (UK)
9 point scale (USA)

56
Q

key points BCS to ensure reproductive efficiency of animal is met (3)

A
  1. Calving
  2. Breeding
  3. weaning
57
Q

what is BCS at calving an indirect measure of

A

pre partum nutrition status

58
Q

effect of post calving nutrition on PPI

A

low plane of nutrition after calving: 55 days

High plane of nutrition after calving: 50 days

59
Q

effect of post calving nutrition on PPI

A
  • Post partum nutrition has not the same impact of reducing the PPI of a beef cow
  • BCS at calving is directly linked to Pre partum nutrition
  • Post partum nutrition is very hard to correct
60
Q

Suckling- LH - Insulin and Ovulation
Relationships

A

slide 35

61
Q

Factors Affecting Probability of
Conception

A
  • accuracy of heat detection
  • accuracy of insemination
  • semen quality factors
  • female factors
62
Q

what are the factors for failure to detect heat

A

cow factors -10%
management factors - 90%

63
Q

what is a primary sign of heat

A

mounting another cow

64
Q

Primary Sign of Heat - slide 40

A
  • key challenge in conception a farmer has to decide
    o The ovulatory event of cow
    o And semen insemination
  • When animal is being mounted: how long will ovulation take place after?
    o 28-31 hours in dairy and beef after sign of first heat
    o Semen needs to go through o process called capacitation -
    o Inseminate 12-18 hours after 1st sign of heat
     AM/PM rule
65
Q

Distribution of heat onset throughout day

A
  • 6-9 in morning and 6-9 in evening
    o Most efficient time
66
Q

when is the most effective timing for conception rate %

A

12-18 hours (interval from detected heat to AI)
- 60% conception rate

67
Q

Factors Affecting the Expression of Heat (2)

A

1.Size of the Sexually
Active Group

2.Under foot surface
Conditions

68
Q

what effect has the underfoot surface on the number mount received during heat

A
  • significant decrease in mounts when cows are on slats - only 14 mounts
  • Oestrus activity could be reduced by 50% with cows on slats
  • Cows on slats are slow in terms are mounting activity
    o 60% are silent heats
  • Introduce teaser bulls on slats which will detect heat
  • highest number of mounts when cows are out on pasture
69
Q

Aids to improve heat detection rate(6)

A
  • Tail paint/ Chalk
  • Heat Mount detectors
  • Scratch Cards
  • Restricted suckling
  • Teaser Bull
  • Synchronisation
70
Q

when using a bull (natural service) what % is infertile and sub fertile

A

3-5% infertile

10-25% sub fertile
- Young bulls die to environmental change/stress
- Change in nutritional diets – stress
 Infertility

71
Q

what way are most suckler cows bred

A

using natural service (>80%)

72
Q

what effect has the presence of a bull

A

expect to advance period to 1st heat
and pregnancy by up to 14 days.

73
Q

if heat detection is accurate and AI
timed and carried out correctly what is the conception rate

A

conception rate is similar following
either AI or natural service

74
Q

what are the conception rates to AI in dairy cows vs Beef cows

A

dairy cows: 52
beef cows: 65

75
Q

what are the problems in using AI for beef cows (4)

A
  • Not as easily detectable in heat
    –> maternal/calf bond
  • More difficult to collect for AI
  • Often located in outfarms with less
    facilities available
  • Many part-time farmers
76
Q

what are the advantages of AI (8)

A
  • Access to proven bulls
    –> Information available on many traits
    –> Use different breeds
  • Knowledge on calving difficulty - use easier calving bulls on heifers
  • Match bull to cow
  • Breed replacement heifers
    –>maternally tested sires
  • Eliminates potential hazard of bull
  • Eliminates specialised housing
    requirements
  • Avoids risk of temporary/permanent
    infertility that frequently occurs with
    natural service bulls
  • Eliminates the risk of introducing or
    spreading disease
77
Q

what is a suboptimal use of AI in beef cow

A

oestrous synchronisation

78
Q

what is seen as major obstacles to AI use

A
  • labour
  • heat dection
79
Q

what is gaining interest in South america

A

use of synchronisation and fixed time AI

80
Q

what are three primary goals for synchronizing oestrus and
ovulation in beef herds:

A
  1. Develop reliable protocols that rely solely on TAI
  2. Develop systems that require a maximum of 3 animal
    handlings
  3. Ensure that systems are successful in anoestrous or
    peri-pubertal and cyclic females at any stage of the
    oestrous cycle.
81
Q

what is a major contributor to poor reproductive efficiency of beef cow herds

A

anoestrus

82
Q

what is the exposure to progesterone

A

is a prerequisite to first
postpartum behavioural oestrus in most cows

83
Q

what does the duration of luteal phase after first PP ovulation often shorter than normal result in

A

an infertile shorter cycle

84
Q

are GnRH/PG based strategies alone are not adequate for anoestrous beef cows

A

no

85
Q

what are Two Main Base Protocols for Beef Cows

A
  1. 7-day CO-Synch + PRID/CIDR:
  2. 5-day CO-Synch + PRID/CIDR:
86
Q

understanding –> 5-day CO-Synch + PRID/CIDR:

A

GnRH administered at
PRID/CIDR insertion, followed 5 d later with PRID/CIDR removal and
administration of 2 injections of PG; the first at PRID/CIDR removal
and second 12 h later. TAI is performed 72 h after first PG and CIDR
removal concurrent with a second GnRH injection

87
Q

understanding –> 7-day CO-Synch + PRID/CIDR:

A

GnRH administered at
PRID/CIDR insertion followed 7 d later with PG at PRID/CIDR
removal. Inseminate 66-72 h after PG and CIDR removal
coincident with GnRH administration.

88
Q

presence/ absence of CL on pregnancy rate

A

NO CL% WITH CL%
No GnRH 47.4% 54.7%
GnRH 49.7% 58.1%
GnRH+ 56.6% 57.2%
eCG

89
Q

what are the Effects of concurrent nutrition on embryo survival rate in heifers

A
  • animals around breeding on a consistent plane of nutrition
  • Embryo survival from cows going from a high to low plane of nutrition
  • When breeding cows you need to have a consistent diet
    o If cows are on a low plane of nutrition, will suffer with milk yield but the % of embryo survival will be the same
90
Q

what happens when you delay the age of first calving from 24 to 36 months

A

it decreases net margin per ha by 50%

91
Q

what is the average age of first calving in beef heifers in ireland

A

31.5 months

92
Q

what % calve for the first time between 22-26 months

A

20%

93
Q

definition of puberty in heifers

A
    • Puberty is defined as the first ovulation followed by a luteal phase of normal duration
  • The onset of sexual maturation
93
Q

in the top 15% of herds, what % of heifers 1st calve at 24 months

A

50%

94
Q

what are the major factors affecting age at puberty

A
  • Breed
  • Plane of nutrition
  • Heterosis
  • Bull effect ?
  • Moderate Heritability
    o Can improve through genetics
95
Q

what factors affect onset of puberty (4)

A
  • hormonal
  • genetic
  • environment
  • nutritional
96
Q

what does GnRH pulse generator central

Neuroendocrine Control of Puberty

A

onset of puberty

97
Q

what goes initially negative E2 feedback turn into

A

Positive Surge release of GnRH

98
Q

where does pre ovulatory surge of LH come from

A

the anterior pituitary

99
Q

what do Different tissues and organs from the body send signals to the
hypothalamus indicating

A

the metabolic status of the animal
slide 82

100
Q

at what age (months) has beef heifers reached what % of mature weight

A

60 to 65% of mature weight at 13.5-14 months

101
Q

at what age (months) has beef heifers reached what % of first breeding

A

65 to 70% at time of first breeding (15 months)

102
Q

at what age (months) has beef heifers reached what % of mature weight at calving

A

85-90% of mature weight at calving (24 months)

103
Q

why is it important to ensure beef heifers reach theses weights (3)

A
  • High proportion cycling regularly at start of breeding season
  • Physically well developed at calving
  • Early resumption of heat activity after calving
104
Q

How are animals measured

A

DMI
* Bodyweight
* Blood sampling
* P4 - > 1ng/ml
* Body composition
* Muscle
* Fat
* Reproductive scanning

105
Q

conception rate % at 1st and 3rd heat post puberty in beef heifers

A

1st heat - 57%
3rd heat - 78%

106
Q

what is the effect of maternal nutrition on postnatal reproductive traits of heifer progeny(3)

A
  • Dams offered 0.6 or 2 x
    maintenance energy requirements
    from -11 to 110 d of gestation
  • Ovarian antral follicle count lower
    for heifers from nutrient restricted
    dams
  • No effect on: - birthweight - postnatal growth - age or weight at puberty
107
Q

what has the maternal nutrition on postnatal reproductive trats have no effect on

A
  • birthweight
  • postnatal growth
  • age o0r weight at puberty
108
Q

Important points on heifers (3)

A
  1. Have heifers well grown at 12 -13 months of age
  2. Restrict breeding to the first 6 weeks of the breeding season and use easy
    calving bulls
  3. Aim for a BCS of 3 at calving
109
Q

important points on cows (3)

A
  1. Monitor BCS through last 1/3 of gestation & adjust feeding accordingly
  2. Calve down cows in moderate to good BCS
  3. Restricted suckling can advance the onset of cyclicity
110
Q

important points on breeding management

A
  1. Avoid fluctuations in feed supply during the breeding season
  2. Heat detection critical when using AI
  3. Vigilance for bull fertility particularly with young bulls

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