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Reproduction > Cattle infertility 1+2 (Fertility, sub-fertility and infertility in the cow) > Flashcards

Cattle infertility 1+2 (Fertility, sub-fertility and infertility in the cow) Flashcards

1
Q

What is a ‘sub-fertile’ cow?

A

one that fails to achieve its fertility target, or that of the herd/group

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2
Q

What is an infertile cow?

A

either a ‘sub-fertile’ cow or a sterile cow

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3
Q

Is cow fertility changing?

A

Yes - lactating cow fertility is decreasing, heifer fertility increasing, milk yield per lactation is increasing

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4
Q

What is the relationship between milk yield and fertility?

A

increasing mil yield –> decreased fertility

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5
Q

What are 4 broad causes of cattle sub-fertility?

A

structural
functional
management
infectious

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6
Q

What are signs of sub-fertility?

A

no observed oestrous
regular or irregular returns to oestrous (after service/AI)
abnormal vulval discharge
abortion and stillbrith

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7
Q

When should a cow cycle?

A

every 18-24 days unless pregnant or within 4-6 weeks post-partum

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8
Q

Reasons for no observed oestrous…

A

congenital abnormalities (ovarian aplasia/hypoplasia, freemartininism)
acyclical or anoestrous
ovarian cysts
no-limited behavioural signs of oestrous (known as a sub-oestrous or silent heat)
poor heat detection

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9
Q

Reasons for no observed oestrous in heifers

A

ovarian aplasia/hypoplasia - v rare - autosomal recessive gene with incomplete penetrance]
Freemartins (due to vascular fusion) - never cycle, small vestigial tract with no ovaries

Dx = by ‘test tube’ or ‘thermometer case’ into vagina (reaches 2-3cm in a freemartin, or about 10cm in a normal animal) and confirmed by karyotype testing

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10
Q

Outline freemartinism

A

92% heifers that are co-twins to bull calves are freemartins.
BE AWARE of single born female freemartins born where the bull calf has died after vascular fusion (i.e. common chorioallantoic sac, separate amnion)

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11
Q

What are the causes of no observed oestrous in COWS?

A 
anoestrous or true acyclicity
COD
Persistent CL
Pyometra + persistent CL
sub-oestrous
failure to detect oestrous
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12
Q

Causes of anoestrous of true acyclicity?

A 
high mil yields
inadequate nutrition (especially energy)
poor BCS
stress (lameness, intercurrent disease)
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13
Q

What are the clinical signs of anoestrous or true acyclicity?

A

rectal palpation shows involuted tract (ovaries feel small, smooth, flat)
ultrasound shows follicles <1.5cm, no CL
milk P4 at 10 day intervals is low (i.e. sequential)

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14
Q

How does inadequate nutrition influence fertility?

A

Inadequate nutrition –> reduced IGF-1 production –> this has 4 main effects:
HYPOTHALAMUS - low GnRH, decreased negative feedback to OE
PITUITARY - decreased LH and FSH secretion, decreased response to GnRH
OVARY - decreased granulosa proliferation and differentiation, decreased aromatase activity, decreased luteal activity and steroidogenesis
EMBRYO - decreased embryo growth, decreased IFNy production

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15
Q

How do you treat anoestrous or true acyclicity?

A

Wait until milk yield falls or cow returns to PEB: increase energy intake if possible
HORMONES: GnRH/analogue, PRID/CIDR +/- GnRH or eCG at a low dose (750 IU)
Better response if nutrition improved concurrently.

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16
Q

What do CIDR and PRID devices look like?

A 
CIDR  = y shaped
PRID = spiral shape
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17
Q

What can be behind fluid-filled structures in bovine ovaries? 5

A

NORMAL: follicles or vacuolated CL
ABNORMAL: luteinised follicles, follicular and inactive cysts, luteal cysts

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18
Q

Describe a follicle:
feeling
size

A

Transient, dynamic, soft, fluctuant
Maximum 1.5-2cm diameter during or just after oestrous
<1.5cm diameter for rest of cycle
associated with normal cyclical acitivity

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19
Q

Describe a vacuolated CL:
feeling/appearance
occurence

A 
same size as non-vacuolated CLs with ovulation point, identifiable with ultrasound
vacuole disappears in pregnancy
usually single
occurs in about 25% ovulations
associated with normal cyclical activity
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20
Q

Describe a luteinised follicle:
size
occurrence/when

A 
<2.5cm diameter
no sign of ovulation
larger cavity than vacuolated CL
usually single formed from anovulatory mature follicle
occur early post-partum
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21
Q

Describe follicular and inactive cysts
appearance
when

A 
soft, thin-walled (2.5cm diamter
single or multiple 
one or both ovaries
formed from anovulatory mature follicle
low P4, cows are anoestorus
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22
Q

Describe luteal cysts:
appearance
when

A

Thick-walled (>3mm), fluid-filled structure, >2.5cm diamter
usually single
formed from anovulation of mature follicle
high P4, cows are anoestrous

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23
Q

What are the main differences between a mature follicle and ovarian cysts?

A

Mature follicle: 2.5cm, persists >10 days. (opinions vary about the presence or absence of a CL concurrently) –> aberrant reproductive function.

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24
Q

What do ovarian cysts develop from?

A

Develop from anovulatory Graafian follicles which instead of ovulating or regressing, the granulosa cell layer degenerates, with cessation of normal cyclical activity with the cow becomes either acyclical or nyphmaniacal

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25
Q

What is nyphomania?

A

where the cow shows persistent oestrous (several days) OR comes into oestrous every 7-8 days and this oestrous lasts longer than normal oestrous (i.e. >18 hours)

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26
Q

What are the different types of cyst? 3

A

TRUE FOLLICULAR: thin-walled, oestradiol-secreting
LUTEAL: thick-walled, progesterone-secreting
INACTIVE: thin-walled, functionally undifferentiated inactive (clinically similar to luteal cyst but structurally more similar to a true follicular cyst - i.e. thin-walled)

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27
Q

Which cyst type is associated with anoestrous? Why?

A

Luteal - because of P4 negative feedback

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28
Q

What do thin-walled follicular cysts result in?

A

acyclicity or, less frequently, nyphomania

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29
Q

What do thick-walled luteal or luteinised cysts result in?

A

acyclicity due to negative feedback of P4 on the anterior pituitary.

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30
Q

What is an increasing problem in high yielders?

A

acyclicity (rather than nyphomania)

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31
Q

What is normal follicular growth for a cow?

A

usually 2 follicular waves with the 3rd –> dominant follicle –> ovulation. This is a ‘3 wave follicular cycle’.

Some cows have a 2 wave follicular cycle. An even smaller % cows have a 4 wave follicular cycle.

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32
Q

Why does ovulation occur?

A

Mature dominant follicle –> increased secretion of oestradiol –> LH surge

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33
Q

Why do cysts occur - broad categories?

A

hypothalamic/pituitary causes

ovarian causes

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34
Q

What are hypothalamic/pituitary causes of cysts?

A

Due to failure of the normal pre-ovulatory LH surge after the end of the recovery period. This may be because of a lack of sensitivity of hypothalamic LH surge centre to oestradiol OR failure of GnRH release.

THUS IT IS A FAILURE OF OESTRADIOL TO ELICIT A NORMAL POSITIVE FEEDBACK STIMULATION OF LH SURGE.

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35
Q

What are ovarian causes of cysts

A

Reduced numbers of LH-Rs in granulosa cells of cysts (versus normal follicles).
OR
Low insulin and IGF-1 and NEB –> increased NEFAs which impair follicular cell proliferation and function.

36
Q

What is this?

A

follicular (thin-walled) ovarian cyst

37
Q

What is this?

A

luteal or luteinised (thick-walled) cyst

38
Q

How can cysts be treated?

Prognosis?

A

Those that develop in the VWP (common for this to occur) –> regress spontaneuosly, no treatment needed
DON’T RUPTURE by squeezing transrectally
Luteal cysts - treat with PGF2a (–> luteolysis)
Follicular: GnRH or hCG (–>luteinisation), followed by PGF2a or CIDR/PRID for 10-12 days

Prognosis - recovery rate is good

39
Q

When might you see a persistent CL? 2

A

High genetic merit cows of extended luteal phase
Uncertainty if it occurs without uterine infections
Occurs associated with pyometra (uterus changes interferes with luteolysin production)

40
Q

How do you treat a persistent CL?

A

PGF2a (removes CL and opens cervix for pus to drain out in case of pyometra/infection)

41
Q

When is oestrous not usually associated with overt behavioural signs?

A

first post-partum oestrous

42
Q

What are signs of oestrous in cow?

A 
Standing to be mounted (min 5 seconds)
Head mounting other cows (learned behaviour?)
clear vulval elastic mucus discharge
bellowing if separated
grouping of sexually active animals
searches for other cows in heat for mounting
restlessness
not eating
decreased milk yield
43
Q

Why might oestrous not be detected?

A 
COW PROBLEM - short oestrous, signs are covert
PERSON PROBLEM (usually) - poor facilites, poor observational regimen
44
Q

How often should cows be observed for oestrous?

A

at least 20-30 minutes, at least 3 times a day, not at milking time, especially between 9-10pm

45
Q

How can you modify ovarian cyclical activity to implement TAI?

A
  • 2 injections PGF2a 11 days apart with a single AI at 72-84 hours after second injection OR double AI at 72 and 96 hour OR 72 and 90 hour after 2nd injection
  • PRID/CIDR for 7-9 days, PGF2a at 24 hour before removal, and double TAI at 48 and 72 hours OR single AI at 56 hours
46
Q

Outline ‘Ovsynch’ - follicle wave synchrony

A

Day 0 - GnRH - synchronise new wave emergnece and accelerate follicular growth
Day 7 - PGF2a - luteolysis
Day 9 - GnRH - control time of ovulation
Day 10 - TAI

47
Q

What is meant by double ovsynch?

A

Prior to Ovsynch programme, you do the traditional presynch:
PGF2a –> wait 14 days –> PGF2a –> wait 12 days –> start normal ovsynch: GnRH, wait 7 days, PGF2a, wait 48-56 hours, GnRH, wait a day, TAI)

48
Q

For what reasons may a cow not calve after service/AI?

A

Oocyte not fertilised (10-15%)

Embryos die abortion, maceration, mummification, abortion

49
Q

At what stage is organogenesis complete in the cow embryo?

A

day 42

50
Q

What is an irregular return to oestrous?

A

Either > 24 days (late embryonic/early foetal death)

mistimed AI)

51
Q

What are non-male reasons for fertilisation failure?

A 
anovulation
delayed ovulation
incorrect TAI
serving too early post-partum
hormonal deficiencies an dimbalance
structural defects of tubular genital tract preventing sperm and oocyte meeting
infection of genital tract and endometritis
nutritional deficiencies and imbalances
stress
52
Q

When does a cow ovulate?

A

About 12 hours after end of oestrous (unique amongst domestic mammals)

53
Q

What are causes of early and late embryonic death?

A

Luteal deficiency and hormonal imbalance
uterine infection with specific embryopathic microorganisms
Infection with opportunist pathogens and endometritis
nutritional deficiencies/excesses
genetic factors
heat and other stressors

54
Q

How do you treat luteal deficiency and hormonal imbalances?

A

difficult to diagnose
some success with P4 supplementation using PRID/CIDR
hCG for 4-9 days post A causes accessory CL formation

55
Q

List some embryopathic microorganisms

A 
Campylobacter foetus
Tritrichomonas foetus
Mycoplasma, ureaplasma and acholeplasma
BVDV
IBR
BTV
Chlamydophila psittaci
56
Q

What is a repeat breeder cow?

A

a cow that has returned to oestrous (not become pregnant) after AI/natural service at normal or extended interval on 3 or 4 consecutive occasions

57
Q

What is an empirical approach to treating a repeat breeder cow?

A
  • change sire if used repeatedly
  • use semen from bull with good fertility (high non-return rates)
  • insemminate at normal time AND 24 hours later
  • nCG or HnRH at time of first AI
  • 11-12 days after AI, GnRH analogue (Buserelin) IM
  • 11-12 days after AI consider using PRID/CIDR
58
Q

What effect may infectious agents have on heifer/cow fertility?

A

Prevent fertilisation
Early embryonic death
Late embryonic death
Abortion/stillbirth/weak calves

59
Q

How can you diagnosie sunclinical endometritis?

A

only way is by taking an endometrial biopsy

60
Q

Define metritis

A

infection and inflammation across all uterine wall layers (myometrium, endometrium and serosal layer)

61
Q

List predisposing factors for endometritis

A 
long/short gestation lenght
RFM (commonest cause)
parity
milk yield
dystocia and trauma (2nd commonest cause)
hygiene
season
intercurrent disease
nutrition
early or delayed return to oestrous
62
Q

Diagnosis for endometritis

A

VAGINAL EXAM ESSENTIAL: dry wipe, clean glove: character, volume and smell
SCORE FOR SEVERITY - MUCUS CHARACTER (0-3) and ODOUR (normal = 0, fetid =3)
BACTERIOLOGY - very difficult

63
Q

List some frequent cases of endometritis

A 
Truperella (Arcanobacterium) pyogenes
Prevotella spp
E. coli
Fusobacterium necrophorum
Fusobacterium nucleatum
64
Q

List some rare causes of endometritis

A 
Acinetobacter spp
Bacillus licheniformis
Enterococcus faecalis
Haemophilus somnus
Mannheimia haemolytica
Pasteurella mutlocida
Peptosptreptoccous spp
S. aurues
Strep. uberis
65
Q

How do you treat endometritis? 3

A

CL PRESENT: PGF2a
NO CL: Metricure = intrauterine cephalosporin
CHRONIC LESIONS: fail to respond to treatment, may consider Pevidene iodine

66
Q

Define abortion

A

expulsion of one or more calves < 271 days after service or AI, either dead or live for < 24 hours

67
Q

Define stillbirth

A

birth of a dead calf at term (272-273 days)

68
Q

List some non-infectious causes of abortion/stillbirth

A

Genetics (chromosome/ developmental abnormalities)
Endocrine deficiencies/excesses
Toxicity
Heat stress
Misuse of therapeutics (corticosteroinds, PGs)
Stillbirth: dystocia

69
Q

What was the most common infectious cause of bovine fetopathy in 2013?

A

Neospora

70
Q

List infectious causes of bovine fetopathy

A 
(IN ORDER OF 2013 frequency)
Neospora
Bacillus licheniformis
S. dublin
Trueperella pyogenes
Schallenberg
Listeria spp
Other fungi
BVD
Campylobacter
Leptospira
71
Q

How often is a specific cause of a fetopathy identified?

A

2006 - 19.3% submissions ID
2013 - 13.7 % submissions ID
Sheep: 40-50% submissions ID

72
Q

When does Brucella abortus cause abortion?

A

6-9 months

73
Q

When do Leptospira species cause abortion?

A

6-9 months

74
Q

When does Campylobacter fetus (venerealis) cause abortion?

A

5-7 months

75
Q

When does Tritchomonas fetus cause abortion?

A

5 months

76
Q

When do Salmonella spp cause abortion?

A

variable time, usually 7 months

77
Q

When does Trueperella (Arcanobacter) pyogenes cause abortion?

A

sporadic and variable time

78
Q

Which infectious causes of abortion are venereal? 2

A 
Campylobacter fetus (venerealis)
Tritrichomonas foetus
79
Q

When can Mycobacterium tuberculosis cause abortion?

A

any stage

80
Q

When can fungi (Aspergillus, Absidia, Mortiella spp, mucoralis group) cause abortion?

A

from 4 months to term

81
Q

When does Bacillus licheniformis cause abortion?

A

sporadic late abotions

82
Q

When Can IBR-IPV virus cause abortion?

A

4-7 months (n.b. venereal)

83
Q

When can BVDV cause abortion?

A

any stage (n.b. venereal)

84
Q

When can Neospora caninum cause abortion?

A

late abortions

85
Q

What is IPV?

A

Infectious pustular vaginitis (a clinical sign of BoHV-1)

86
Q

What are two possible clinical signs of BoHV-1?

A

IBR and IPV

Reproduction (42 decks)

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