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Farm (year 4) > Reproduction > Flashcards

Reproduction Flashcards

1
Q

where is the main control point for the reproductive endocrinology?

A

hypothalamus

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2
Q

what hormone is released from the hypothalamus that controls reproduction?

A

GnRH

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3
Q

what does GnRH work on in the endocrine reproductive pathway?

A

pituitary gland

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4
Q

what does GnRH trigger to be released from the pituitary gland?

A

FSH and LH

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5
Q

what is GnRH?

A

gonadotrophin releasing hormone

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6
Q

what does FSH do?

A

stimulate development of follicles in the ovary (follicle stimulating hormone)

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7
Q

what does LH do?

A

causes the dominant follicle to ovulate and triggers it to lutenise to become a corpus luteum

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8
Q

what does the follicle produce as its developing?

A

oestrogen

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9
Q

what are the effects of oestrogen on the reproductive endocrinology?

A

negative feedback on FSH (stop other follicular development)
gives signs of heat

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10
Q

what does the follicle develop into after ovulation?

A

corpus luteum

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11
Q

what hormone is produced by the corpus luteum?

A

progesterone

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12
Q

what is the function of progesterone?

A

prepare the uterus for pregnancy (if CL isn’t lysed)

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13
Q

what is the first stage of the follicle developing into a CL?

A

corpus haemorrhagicum

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14
Q

what does oestrogen have negative feedback on?

A

brain (neurotransmitters)
hypothalamus (GnRH)
anterior pituitary (LH/FSH)

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15
Q

what happens to the first follicle after calving?

A

not exposed to progesterone so is smaller and produces less oestridioll

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16
Q

why is the first cycle after calving often silent?

A

no progesterone so the follicle is smaller and produces less oestradiol so no/less signs of heat are seen

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17
Q

what does progesterone have a negative feedback on?

A

LH (no ovulation can occur shortly after another)

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18
Q

how is metoestrus usually detectable?

A

small amount of blood on vaginal exam
small ovaries on rectal

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19
Q

how do pulses of LH change as ovulation gets nearer?

A

the pulses increase in frequency (causing increase in blood levels)

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20
Q

how long does it take dairy and beef cows to return to cycling?

A

dairy cows usually within a few weeks
beef cows can take a few months

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21
Q

what is the best sign of oestrus?

A

cow stands to be mounted

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22
Q

what are the signs of oestrus?

A

vulva swelling and mucus discharge
holding milk
restless
mounts other cows
chin resting
standing to be mounted

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23
Q

which cow is in heat if one is sniffing another vulva?

A

the cow doing the sniffing is in oestrus

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24
Q

if a cow is chin resting on another which is in oestrus?

A

both of them

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25
Q

if cows are bunting each other, which one is in oestrus?

A

both of them

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26
Q

if a cow mounts another head to head, which is in oestrus?

A

the one doing the mounting

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27
Q

if a cow mounts another, which is in heat?

A

the one standing to be mounted

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28
Q

when should a cow seen standing to be mounted be served?

A

AM PM rule (if seen in morning serve in evening)

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29
Q

what is the best time to inspect cows for heat detection?

A

when they are resting and the barn is quiet - not about to be milked or moved around

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30
Q

what are some heat detection aids?

A

paint/chalk or kamars
record keeping (21 day cycle)
teaser animals
milk progesterone (decreases detected)
activity monitors

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31
Q

what are the limitations for mount detectors?

A

not all cows show standing heat, can be hit/rubbed by brushes

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32
Q

how do activity monitors detect heat?

A

monitor ever few hours to get a basal activity level, then creates a mean
if there is movement more than 5 standard deviations away from the mean it is marked as in oestrus

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33
Q

how does rumen activity change in oestrus?

A

decreases

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34
Q

how many sperm are in an AI straw on conventional semen?

A

20 million

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35
Q

how many sperm are in an AI straw of sexed semen?

A

1 million

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36
Q

how are AI straws thawed?

A

in a water bath at 37 degrees for 40 seconds

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37
Q

what is the role of KPIs?

A

demonstrate efficiency of herd
show good animal health/welfare
provides a benchmark to aim for

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38
Q

what are the requirements of a good KPI?

A

measurable
convenient
low cost

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39
Q

where could data be available for analysis of a herd?

A

legal farm records (medicine, movements…)
product purchaser (deadweight, milk sales…)
from supplies (feed input, AI straws…)
veterinary computers
farm diary
milk recording (NMR, CIS…)

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40
Q

what are some specific KPIs for monitoring fertility?

A

submission rate (number of animals severed out of number that are eligible)
first service submission rate (all animals who haven’t been served after the earliest service date)
calving to first service
calving interval
calving to conception interval
in calf rate (by 100 days…)

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41
Q

what is the issue with using calving interval as a KPI?

A

must have had two calves (doesn’t take into account a large portion of the herd)

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42
Q

what is the issue with using calving to conception interval as a KPI?

A

will get worse as animals conceive (problem cows will conceive last)

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43
Q

what is the conception rate?

A

number of pregnancies for those cows who have been served

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44
Q

what is the main advantage/disadvantage of late PDing?

A

advantage - more predictable of those who will hold the calf
disadvantage - longer before you can do something about the negative cows

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45
Q

what is preg rate?

A

number of pregnant cows over the number of which are eligible to be pregnant (over 3 weeks)

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46
Q

when does the heart begin beating in an embryo?

A

23 days

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47
Q

when does the maternal recognition of pregnancy occur?

A

15 days

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48
Q

what is a cu-sum for tracking conception rate?

A

graph where the line moves up one if the PD positive and down if they PD negative (gives you a conception rate) - can pinpoint times when things went good/bad

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49
Q

what does inter service interval tell you?

A

how accurate the heat detection is (should be 3 weeks)

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50
Q

where does fertilisation occur?

A

oviduct

51
Q

what hormone is crucial for embryo growth?

A

progesterone

52
Q

how does maternal recognition of pregnancy occur in cows?

A

size of embryo determines this, as it produces interferon (bigger the embryo the more interferon and more successful the MRP will be)

53
Q

what happens if there is no implantation of an embryo in cattle?

A

oxytocin is able to bind to its receptors which triggers prostaglandin F2alpha and lysis of the CL occurs

54
Q

what is the interferon for maternal recognition of pregnancy?

A

interferon tau

55
Q

what day does the embryo become visible to scanning?

A

27/28

56
Q

what hormone maintains pregnancy?

A

progesterone

57
Q

what is the hormonal triggers of parturition?

A

calf stress produces cortisol which triggers prostaglandin release and reduced progesterone

58
Q

what organs does cortisol from the calf at parturition aid the development of?

A

lungs

59
Q

what has to happen after calving for the successful establishment of the next pregnancy?

A

involution of uterus
restoration of endometrium
resumption of ovarian cycling
insemination/fertilisation

60
Q

what are the levels of hormones after calving?

A

oestrogen and progesterone are low
FSH surges increase after a few days

61
Q

what are some reasons for early embryonic loss?

A

(fertilisation failure)
uterine environment
infectious agents (BVD, lepto…)
metabolic status of dam
genetic abnormality

62
Q

what are some issues seen post calving by a vet/farmer?

A

retained foetal membranes
metritis/endometritis
cystic ovarian disease
failure to resume cycling

63
Q

what is a possible cause for irregularly cycling of served cows?

A

insufficient interferon tau being produced causing early embryonic death as it can’t implant

64
Q

how long does a placenta have to stay in the cow to be classed as a retained foetal membrane?

A

24 hours

65
Q

what are the consequences of retained foetal membranes?

A

low milk yield
longer time to involute (longer to resume oestrus cycling)
metritis, endometritis, pyometra

66
Q

what is metritis?

A

infection of the uterus up to 21 days post calving

67
Q

what are the consequences of uterine infections?

A

damage to uterus
suppress hypothalamic GnRH secretion
localised effect on ovarian function

68
Q

what are the main pathogens for uterine infection?

A

E. coli
Truperella pyogenes
Dichelobacter nodosus
(bovine herpes virus 4)

69
Q

what are some possible risk factors for retained foetal membranes?

A

reduced dry matter intake in dry period
negative energy balance after calving
vitamin A/D/E deficiency
iodine deficiency

70
Q

what are is grade 1 metritis?

A

enlarged uterus and purulent uterine discharge but no pyrexia/illness

71
Q

what is grade 2 metritis?

A

overt systemic illness (pyrexia, milk drop…)

72
Q

what is grade 3 metritis?

A

toxaemic metritis

73
Q

what is pyometra?

A

accumulation of purulent material within the uterine lumen in the presence of a CL and closed cervix

74
Q

what is done to treat a pyometra?

A

prostaglandin (lyse CL)

75
Q

what is clinical endometritis?

A

presence of purulent uterine discharge detectable in the vagina over 21 days post calving

76
Q

what is a grade 1 uterine discharge score?

A

flecks of off white pus

77
Q

what is grade 2 uterine discharge score?

A

<50% off white material

78
Q

what is grade 3 uterine discharge score?

A

> 50% off white material and possibly blood stained

79
Q

what grade endometritis is treated?

A

grade 2 and 3

79
Q

what grade endometritis is treated?

A

grade 2 and 3

80
Q

what is sub-clinical endometritis?

A

high neutrophil count in the uterus (no discharge or bacteria)

81
Q

what are the risk factors for sub-clinical endometritis?

A

negative energy balance
metritis

82
Q

how is sub-clinical endometritis diagnosed?

A

can only be done by flushing uterus with saline or a cytobrush

83
Q

what is a follicular cyst?

A

a follicle that hasn’t ovulated and has kept growing

84
Q

what is a luteal cyst?

A

a follicular cyst that has lutenised

85
Q

what are some risk factors associated with cystic ovarian disease?

A

high milk production
negative energy balance
ketosis
higher parity
twinning and peri-parturient problems
excess BCS
genetics

86
Q

if there is a CL (>2cm) present on one ovary and a follicular cyst on the other, what should be treated?

A

CL (follicular cyst will be hormonally inactive)

87
Q

what are the features of a follicular cyst?

A

thin wall
fluid filled
been there more than 10 days
>25mm

88
Q

how active is a follicular cyst if there are other follicles present on the ovary?

A

cyst inactive (not secreting estradiol)

89
Q

what are the features of a luteal cyst?

A

> 25mm
thick wall
fluid filled lacuna
been there more than 10 days

90
Q

what are the treatment options for follicular cysts?

A

burst
GnRH
progesterone (PRID/CIDR)
aspirate

91
Q

what is done to treat a luteal cyst?

A

prostaglandin

92
Q

what is abortion defined as?

A

calving that occurs <270 days of gestation

93
Q

what disease is the reason abortions need to be reported?

A

brucellosis

94
Q

what is the statutory testing for brucellosis?

A

blood, vaginal swab and milk (if possible)

95
Q

what are infectious primary abortion agents?

A

pathogens that cross the feto-maternal barrier

96
Q

what are some possible non-infectious causes of abortion?

A

nutrition - iodine, selenium, energy balance
developmental - hormones, congenital abnormalities
toxins - aflatoxins, nitrate
trauma, hyperthermia, twinning

97
Q

what are some possible target tissue of abortion agents?

A

chorio-allantois
amnion
bone
soft tissue
endocrine glands
immune cells of foetus

98
Q

what is the definition of a primary abortive agent?

A

agent that destroys the integrity of the fete-maternal unit allowing opportunistic pathogens to invade the placenta/fetus

99
Q

what are some primary infectious abortion agents?

A

brucella abortus
BVD
leptospirosis
neospora
BHV-1
parainfluenza 3
bacillus licheniformis
fungi

100
Q

what are the main opportunistic pathogens causing abortion?

A

Listeria monocytogenes
Leptospira borgpetersenii
Salmonella dublin

101
Q

what are the three routes of infection for abortion pathogens?

A

resident flora of reproductive tract during pregnancy
transplacental
haematogenous

102
Q

when in gestation does the foetus become able to differentiate between antigen and self?

A

90-120 days

103
Q

what in the pathogen for IBR?

A

bovine herpesvirus 1

104
Q

where is BHV-1 found during latent infection?

A

trigeminal ganglion

105
Q

how can a vaccine be used for IBR?

A

protection in the face of an outbreak

106
Q

what is the most commonly diagnosed cause of abortion in cattle?

A

neospora

107
Q

when does neospora usually cause abortion?

A

mid gestation

108
Q

how many abortions does neospora cause per cow?

A

only one (usually)

109
Q

what are the possible outcomes of a cow with neospora? (in terms of pregnancy)

A

10% abortions
80% persistant infection
10% normal/weak

110
Q

why is neospora difficult to diagnose in cattle?

A

maternal antibodies fluctuate throughout reproductive cycle

111
Q

when is the best time to test for neospora antibodies in dams?

A

just after dry off

112
Q

what is the best way to diagnose neospora?

A

test calf before its had colostrum

113
Q

how can neospora be controlled?

A

keep dogs away from feed and placentas
culling seropositive animals/offspring
breed to beef
sexed semen in unaffected heifers

114
Q

what are the possible outcomes of BVD if infected during pregnancy?

A

early - resorption/abortion
90-120 days - immunotoleranc (PI animal)
late - sero-positive and congenital abnormalities

115
Q

what biotype of BVD causes issues in pregnant cattle?

A

non-cytopathic

116
Q

what are the classic congenital abnormalities of BVD?

A

cataracts
cerebellar hypoplasia

117
Q

what is the antibody and antigen status of PI BVD calves?

A

antibody negative
antigen positive

118
Q

what causes mucosal disease?

A

PI BVD animals that become infected with the cytopathic biotype

119
Q

what are the possible ways to diagnose BVD?

A

bulk milk antibody
PI in blood from 1 months of age
ear notch test
antibody using bloods

120
Q

how is BVD controlled?

A

test bought in cattle
good biosecurity
test and cull
vaccine (just protects first pregnancy)

121
Q

why is leptospirosis a concern in the parlour?

A

excreted in urine and is zoonotic

122
Q

what are to clinical signs of leptospirosis?

A

abortions, stillbirths, weak calves, retained foetal membranes, infertility

123
Q

how can clinical leptospirosis be treated?

A

antibiotics - oxytetracycline or dihydrosteptomycin

Farm (year 4) (17 decks)

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