Bovine Breeding Programs

Question 1

what is the biological minimum voluntary waiting period

Answer 1

50 days

Question 2

is estrus detection a challenge in the dairy industry

Answer 2

yes, a big one

Question 3

do cows and heifers have the same amount of estrus events and length of duration

Answer 3

No. Heifers have a longer duration and more events compared to multiparous animals. nearly double the amount of events

Question 4

is there a difference in estrus behaviour between low producers vs high producers

Answer 4

technically yes, but its a trivial difference

Question 5

what proportion of cows presented for AI that arent in heat when using visual detection

Answer 5

~17%

Question 6

what proportion of cows presented for AI that arent in heat when using observation of standing only

Answer 6

5%

Question 7

what proportion of cows presented for AI that arent in heat when using tail chalk

Answer 7

6% but there is a decent range (0-14%)

Question 8

what proportion of cows presented for AI that arent in heat when using only secondary signs in tie stalls

Answer 8

22%

Question 9

what proportion of cows presented for AI that arent in heat when using activity meters

Answer 9

4-9%

Question 10

what is the “gold standard” for heat detection in cows

Answer 10

standing heat

Question 11

what is most easily manipulated in cows?

Answer 11

insemination risk

Question 12

what is insemination risk

Answer 12

proportion of eligible cows detected in heat. AI submission rate

Question 13

what is conception risk

Answer 13

probability that AI results in pregnancy or proportion of breedings that result in dx of pregnancy

=pregnancy per AI

Question 14

what is 21 day pregnancy risk

Answer 14

roughly = heat detection rate x conception risk

the proportion of open cows that become pregnant every 21 days

Question 15

is heat detection always necessary?

Answer 15

not always if you are using synchronization

Question 16

what does GnRH cause release of

Answer 16

LH and FSH

Question 17

what are the effects of LH

Answer 17

causes ovulation of mature dominant follicles

Question 18

what is the purpose of progesterone

Answer 18

-prevents an LH surge (ovulation) and sensitizes the brain to estrogen to allow for an LH surge later (when P4 is low)

Question 19

what hormone supports embryo growth

Answer 19

progesterone

Question 20

PGF, GnRH and P4 are _____

Answer 20

naturally occuring

Question 21

what is the half life of PGF

Answer 21

minutes

Question 22

where does prostaglandin come from naturally

Answer 22

endometrium

Question 23

is giving hormones bad for the cow

Answer 23

not if its within physiological limits

Question 24

what does it mean if a cow “no shows”

Answer 24

cant see the heat she is demonstrating

Question 25

what is important to remember about heat and confinement of tie stalls

Answer 25

you will never see her in standing heat because no other cows will be available to mount her

Question 26

what can affect heat detection? (8)

Answer 26

-intensity (of looking) -accuracy (actually seeing it) -confinement -lameness -flooring (if slippery) -cow comfort -severe or prolonged NEB -repro tract dz

Question 27

what is the lifespan of the ovum

Answer 27

6-8 hours - super short

Question 28

what is the relationship between time sperm arrives and capacitation to fertilization

Answer 28

first sperm will reach egg in 3-4 hours but capacitation take 8-10 hours so the sperm that arrives the fastest are not the ones to impregnate the cow

Question 29

what is the single weakest link in the process of getting a cow pregnant

Answer 29

heat detection!

Question 30

what is involved in estrus synchronization (overview)

Answer 30

-prostaglandin shots to individual cows -scheduled prostaglandin shots to groups

Question 31

what % of cows are detected with activity monitors per cycle

Answer 31

60-80%

Question 32

what is an example of a mount detector

Answer 32

tail paint

Question 33

what is a pro of using tail paint

Answer 33

can have detection without having to keep an eye on them 24/7

Question 34

what is the accuracy of rectal palpation for functional CL

Answer 34

75%

Question 35

what is the accuracy of ultrasound scanning

Answer 35

90%

Question 36

when is the CL responsive to prostaglandin

Answer 36

on day 7 of the 21 day cycle

Question 37

when is a CL naturally lysed

Answer 37

day 18 of 21

Question 38

if you give prostaglandin to a group of cows without knowing where they are in their cycle, what % will show an apparent estrus response

Answer 38

~2/3 50% due to the shot and 16% due to her own natural prostaglandin being present

Question 39

does prostaglandin do anything to the follicles

Answer 39

no

Question 40

why is there a variable time of ovulation after prostaglandin is given

Answer 40

she may have had a dominant follicle ready so ovulation <2 days or she may have a small follicle that needs a bit more time to be ovulated so 2-5 days

Question 41

does prostaglandin allow for timed AI

Answer 41

no because it has no control on the follicles

Question 42

what is a pro of controling when a cow ovulates

Answer 42

you know when to inseminate her and you dont need to see heat

Question 43

why is GnRH critical on day 1 of an ovsynch program

Answer 43

it stimulates LH.... which is critical to initiate a new follicular wave and ensure a new dominant follicle is ready by day 10!!

Question 44

what are the steps in an ovsynch protocol

Answer 44

1. give GnRH on day 1 2. give prostaglandin shot at AM milking of day 7 3. give GnRH shot at PM milking on day 9 4. BREED in the morning on day 10

Question 45

what is the length of time needed between each step of the ovsynch protocol

Answer 45

-between step 1 and 2 = 1 WEEK -between step 2 and 3 = 48-56 HOURS -between step 3 and 4 = 12-16 HOURS

Question 46

what are the critical control points for optimizing an ovsynch protocol (5)

Answer 46

-start new follicular wave after 1st GnRH -ovulate after 1st GnRH -luteolysis after prostaglandin -ovulation after 2nd GnRH -insemination 16hours after 2nd GnRH

Question 47

when is it best to start an ovsynch protocol

Answer 47

approx 1 week after a heat so you can get an extra CL (better fertility)

Question 48

what happens if you ovsynch 1-4 days after heat

Answer 48

failure of synchronization of new follicular wave

Question 49

what happens if you ovsynch 13-17 days after heat

Answer 49

spontaneous luteolysis and ovulation before timed AI

Question 50

what happens if you ovsynch 18-21 days after heat

Answer 50

unresponsive CL at time of PGF

Question 51

what is the best program for farms

Answer 51

whatever one gets done correctly and consistently

Question 52

why would you pre-synch a cow

Answer 52

pre sync the estrus cycle so that cows are 6-7 days after an ovulation at the start of an ovsync

Question 53

what do you do for a normal presync

Answer 53

-2 prostaglandin shots 14 days apart -do it 11-14 days before you start ovsync

Question 54

what do you do for double ovsync

Answer 54

- ovsync but dont AI, wait a week and then ovsync again and AI at the end

Question 55

what does pre-synching achieve

Answer 55

increases the probability of pregnancy with an ovsync program by optimizing response to elements of the program

Question 56

what is the purpose of inserting a CIDR (3 outcomes)

Answer 56

-prevents ovulation in cyclic cows -stimulates ovulation in anestrus cows -stimulates turnover in cystic cows

Question 57

what happens when a CIDR is in for more than 14 days

Answer 57

produces persistent dominant follicle with decreased fertility

Question 58

when would you use an ovsynch and CIDR impant protocol

Answer 58

for treatment of anovular animals and cystic ovarian condition

Question 59

when do you insert the CIDR in an ovsync/P4 protocol

Answer 59

insert after you give the first GnRH shot, leave in for a week and take out once you give the prostaglandin shot