Lecture 2: Bovine Infertility (Risco)

Question 1

infertility = sterility ?

Answer 1

NO.

Question 2

T/F: infertility is a sign, not a specific condition

Answer 2

T

Question 3

T/F: there are both infectious and non-infectious causes of infertility

Answer 3

T

Question 4

estrus vs. estrous

Answer 4

estrus: a noun “a cow displays estrus”
estrous: an adj. “the estrous cycle”

Question 5

most common form of infertility

Answer 5

non-infectious (esp. due to lack of detection of estrus)

Question 6

main causes of non-infectious infertility

Answer 6

cow is in anestrus due to failure to detect estrus** or failure to exhibit estrus. If the latter occurs, the cow is in true anestrus and something is likely actually wrong with the cow.

Question 7

1ary sign of estrus

Answer 7

standing to be mounted

Question 8

methods to help improve detection of estrus

Answer 8

• heat detection aids

- synchronization of estrus or ovulation (i.e. using Ovsynch protocol or PGF2a)

Question 9

Heat detection aids

Answer 9

• Pressure activated device
• Tail chalks/paints
• Pressure detector (heatwatch) -detects when cow being mounted
• Activity monitoring systems (accelerometer, pedometer, collar)

Question 10

detection of cows displaying estrus (AI submission rate) determines:

Answer 10

when cows are first bred at the end of the VWP

Question 11

activity monitors measure:

Answer 11

• activity
• laying bouts
• laying time
• rumination

Question 12

example of a heat detection aid

Answer 12

HeatWatch II system. When cow mounts another cow, it triggers a sensor which alerts a computer of the event

Question 13

Ovsynch TAI Protocol

Answer 13

(ovulation occurs before d0)
d0: give GnRH
d7: give prostaglandin
d9: give GnRH
d10 (16 hours post-GnRH): TAI (Timed Artificial Insemination)

Question 14

How to synchronize estrus for AI (not Ovsync)

Answer 14

d0: give PG
d14: give PG again
d16-21: AI

Question 15

Describe how Progesterone (P4) lvls change throughout OvSync protocol

Answer 15

At ovulation (before d0), progesterone starts at a very low level then steadily increases before plateauing around 7 ng/ml just before d0, when GnRH is given. Plateau continues until d7, when PG is given. P4 then drops off to a negligible level around d8.5. GnRH given again at d9 and then TAI started at d10. (See slide 15)

Question 16

When do follicular waves occur in Ovsync?

Answer 16

First wave starts at ovulation when P4 is increasing before d0. Second wave starts around d2-3 and ends after d10 when TAI is occuring.

Question 17

Presynch-Ovsynch protocol

Answer 17

d0: PGF
d14: PGF
d26: GnRH
d33: PGF
d35: GnRH
d36: TAI

Question 18

anestrus =

Answer 18

failure to exhibit estrus

Question 19

causes of anestrus**

Answer 19

poor nutrition, neg. energy balance, debilitating dz
cystic ovaries or tumors
endometritis/pyometra
congenital defect
pregnancy
heat stress
rBST (bovine somatotropin)

Question 20

peak milk production occurs how many weeks post-partum?

Answer 20

4

Question 21

When does peak dry matter/energy intake occur?

Answer 21

6-8 weeks post-partum

Question 22

where does most energy for peak milk production come from?

Answer 22

mobilized fat (lose BC as a result)

Question 23

most cows lose how many BCS post-partum?

Answer 23

1

Question 24

When does cow return to positive energy balance post-partum?

Answer 24

8 weeks post-partum (when dry matter intake is peaking)

Question 25

what does neg. energy balance disrupt?

Answer 25

hypothalamic pituitary axis. Pushes cow nearer to ketotic. - glucose low - free fatty acids high - ketone bodies high

Question 26

nadir

Answer 26

lowest point in negative energy balance

Question 27

SEE SLIDE 19

Answer 27

:)

Question 28

GnRH secreted by:

Answer 28

hypothalamus

Question 29

increased insulin --> response to LH

Answer 29

increases

Question 30

inc. response to LH --> estradiol (E2)

Answer 30

inc.

Question 31

describe LH pulses before and after NADIR. Why?

Answer 31

before: low and infrequent after: higher and more frequent because there is more GnRH and FSH coming from the pituitary and cow will then ovulate

Question 32

cow will only ovulate past the ___ of NEB

Answer 32

nadir

Question 33

in well managed herds, ovulation can reach what percentage?

Answer 33

80-90% (those that fail to ovulate still have some NEB and must wait to ovulate until they peak their DM intake)

Question 34

average fate of dominant follicle of first wave

Answer 34

``` ovulate: 50% don't ovulate: 25% becomes cystic (follicular or luteal): 25% ```

Question 35

follicular cyst

Answer 35

follicle that fails to ovulate because there isn't enough LH | -produces NO progesterone

Question 36

luteal cyst

Answer 36

forms because there was only enough LH to cause a PARTIAL ovulation. -surrounded in basement membrane (luteal tissue)

Question 37

which species are more prone to cysts?

Answer 37

cats, cow, horses

Question 38

which cyst is more common: follicular or luteal?***

Answer 38

luteal

Question 39

What is a CL?

Answer 39

a follicle that fails to ovulate. Does not form corpus hemorrhagicum

Question 40

Does luteal cyst produce progesterone?

Answer 40

Yes (but only some). Progesterone that is produced keeps cow in estrus

Question 41

When is there no tonicity in the uterus?

Answer 41

during proestrus and estrus

Question 42

If you feel no CL and large follicular degeneration, could be:

Answer 42

cow could be coming into estrus, OR may be follicular cyst

Question 43

CS of cystic follicular degeneration

Answer 43

- frequent estrus - irregular estrouscycles - anestrus

Question 44

Dx of cystic follicular degeneration based on:

Answer 44

- anovulatory follicle(s) >25mm ** - No CL** - check twice 10d apart** - lack of uterine tone/flaccid uterus