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Module 22: Reproduction & Fertility > Sub/Infertility in Dairy Cows > Flashcards

Sub/Infertility in Dairy Cows Flashcards

1
Q

what are reproductive parameters used to measure fertility in dairy cows

A

% served by day 80 post partum

% conceived 100 days after calving

Age at first calving

Calving interval

Conception rate

% cows eligible for service served (submission rate)

% eligible for service that conceived (pregnancy rate)

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2
Q

what % should be served by day 80 post partum and why

A

In order to maintain yearly calving interval

After voluntary waiting period (about 50-60 days)

Target 68%

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3
Q

what % should have conceived 100 days after calving

A

41

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4
Q

what should the age at first calving be

A

2 years

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5
Q

what should the calving interval be

A

387d

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6
Q

what is a target conception rate

A

42

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7
Q

what should the % cows eligible for service served (submission rate)

A

>67

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8
Q

what should the % eligible for service that conceived (pregnancy rate)

A

>25

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9
Q

what is the relationship between yield and the affect 1st ovulation and 1st heat expression

A

negative relationship between milk yield and heat expression or detection (STBM) and first service pregnancy rate (FSPR)

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10
Q

what are the effects of post partum disease on 1st ovulation and heat expression

A

severely affected by transition diseases and postpartum conditions such as

C section

Lameness

Endometritis

RFM

Dystocia

Mastitis

Milk fever

Low BCS

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11
Q

how does negative energy balance affect the # of days open

A

Energy balance start of recovery in 1st week postpartum

  • Ovulation of first dominant follicle 2 weeks pp

Energy balance nadir 2nd week pp

  • Dominant follicle turnover —> 1st ovulation 5 weeks pp

In very severe energy balance nadir to 14d pp:

  • Dominant follicle turnover —> no ovulation by 6 weeks post partum
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12
Q

what is the effect of uterine E coli infection and follicular and luteal levels

A

e coli lowers production

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13
Q

what are NDO cows

A

not detected in estrus

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14
Q

what do NDO cows lead to

A

low submission rates <40%

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15
Q

what could be some causes of NDO in cows

A
  1. low BCS pp and anovulation
  2. reduced estrous behaviour and duration in high yielding cows (sub-estrus)
  3. cystic ovarian disease
  4. metritis and clinical/subclinical endometritis
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16
Q

how does low BCS loss pp lead to anovulation

A

Severe loss in BCS pp causes DF turnover and anovulation

The more BCS lost the longer they take until first ovulation

High risk of severe BCS loss pp —> over conditioned during the dry period, they lose more BCS

Higher BCS means suppression in DMI and causing a more severe negative energy balance

17
Q

what are the consequences of prolonged post partum anestrus for reproductive performance

A

Days to first service +26 days

Conception rates -18% (first service)

Time to conception +41 days

18
Q

what does severe loss in BCS pp cause

A

DF turnover and anovulation

19
Q

why do high yielding cows have reduced estrous behaviour and duration

A

High metabolic rate

  • High feed intake
  • High blood flow
  • High liver blood flow: 40% higher in lactating animals vs non-lactating
  • Leads to higher metabolic rate and the E2 and P4 are metabolized quicker and cleared, excreted by kidneys quickly
  • Decreased circulating concentrations of ovarian estradiol and progesterone causing sub-estrus and also lowering fertility
  • Reduced negative feedback from estradiol will lead to an increase FSH and ovulation of co-dominant follicles
20
Q

why are high yielding dairy cows more prone to twinning

A

High liver blood flow: 40% higher in lactating animals vs non-lactating

Leads to higher metabolic rate and the E2 and P4 are metabolized quicker and cleared, excreted by kidneys quickly

Reduced negative feedback from estradiol will lead to an increase FSH and ovulation of co-dominant follicles, thus twinning

>20% or more in high-yielding dairy herds

21
Q

what is the definition of cystic ovarian disease

A

follicle from 20mm (or from 16mm?)

fluid filled and thin walled

interferes with cyclicity (anovulatory, NDO)

no functional CL tissue >10d

22
Q

what are the two different types of cysts

A
  1. follicular
  2. luteal
23
Q

what do follicular cysts cause

A

lack of ovulation

24
Q

what is the wall thickness of follicular cysts

A

thin walled

25
Q

what do follicular cysts secrete

A

estrogen

26
Q

what do luteal cysts cause

A

slow luteinization but no ovulation

27
Q

what is the wall thickness of luteal cysts

A

thick walled

28
Q

what do luteal cysts secrete

A

progesterone

29
Q

what kind of cyst is shown here

A

follicular cyst

thin outer wall with black fluid extending to its outer edges

presence of a second follicular cyst is evident on the left side of the ovary as well

30
Q

what is shown here

A

benign follicluar cyst very prominent on the left side of the ovary, but can be classified as benign due to the corpus luteum sitting to the right of it.

31
Q

what is shown here

A

luteal cyst

they often progress into luteal cysts by forming a thicker wall of luteal tissue around their outer edges

very slight bit of white “cobwebs” within the lumen of the luteal cyst where the cyst appears to be attempting to further luteinize

32
Q

what is shown here

A

luteinization has occurred along the bottom rim of the cyst and again the cobwebs of fibrous tissue are attempting to luteinize the rest of the cyst, but the upper portion of the lumen is still fluid-filled

33
Q

what is shown here

A

luteal cyst (on the right side of ovary) in its early stages where the thin outer walls of the cyst still resemble that of a follicular cyst, but the cobwebs are apparent throughout the lumen as the cyst attempts to luteinize. You can see a second cyst on the left side of the ovary as well

34
Q

what are at risk animals to cystic ovarian disease

A

Dairy cows early post partum

  • esp if high BCS at calving due to long dry period

High yielders and older cows

Severe negative energy balance/BCS loss and suffering from metabolic diseases

High NEFAs, fatty liver, ketosis

Uterine pathology post partum

  • Twins, RFM, metritis

Increase phytoestrogens for long time

  • Red clover pasture
35
Q

what are the severe consequences of cystic ovarian disease for repro performance

A

Days to first service +6-11d

Conception rates: reduced (first service)

Time to conception: +20-30d

36
Q

how are cystic ovarian diseases diagnosed

A

Nymphomania

Virilism

  • Male-pattern hair growth and other masculine physical traits

Anovulation and anestrus, NDO cows

Irregular estrus

37
Q

what are the treatments for follicular cysts

A

GnRH to cause ovulation of follicular cyst

Progesterone devices to cause atresia of follicular cyst

GnRH will cause the cyst to luteinize and subsequent treatment with prostaglandin F2α will resolve the luteinizing cyst by triggering luteolysis

38
Q

how are luteal cysts treated

A

PGF2a

luteolysis of luteal cyst

Because some early luteal cysts are not yet responsive to prostaglandin F2α, another approach includes treatment with GnRH first and then prostaglandin F2α in order to further luteinize the cyst with GnRH and then administer prostaglandin F2α to resolve it

Module 22: Reproduction & Fertility (27 decks)

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