Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Food Animal Therio > Small Ruminant Repro Management > Flashcards

Small Ruminant Repro Management Flashcards

1
Q

What does it mean that small ruminants are seasonally polyestrous?

A

They have multiple estrous cycles restricted to a certain period of the year
- they are short day breeders and the onset and length of the breeding period is variable according to photoperiod, latitude and climate, food availability, breed, presence of a male, breeding system, physiological stage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

T/F: the closer to the equator sheep are the longer their breeding season will be

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe the physiology of the seasonal estrous cycle

A

When in season, eye detects decreased light, which decreases firing of retinal nerves and excitation from superchiasmic nucleus–> inhibition of pineal gland resulting in increased melatonin
- increased melatonin generates GnRH, FSH and LH pulsatility to initiate cycling
-opposite in the mare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What factors influence the start of puberty in small ruminants?

A

Age, nutritional status, season, breed, exposure to male

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What age do rams/bucks usually go through puberty? Does? Pigmy goats? Ewes?

A

Rams/Bucks: 4-6 months
Does: 6-8 months
Pygmy goats: 3 months
Ewes: 6-9 months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

At what percent of adult body weight should a small ruminant be prior to breeding?

A

60-70%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why are ewes usually bred via laproscopic AI?

A

They have a very tortuous fibrocartilaginous cervix
- they have 6-8 cervical rings vs goats that have 4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How long is the cycle of goats and sheep? How long is estrus?

A

Sheep: 14-19 days (average 17), estrus 30-36 hrs
Goats: 18-22 days (average 21), estrus 24-48 hrs
- pigmy goats can vary from 18-24 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

T/F: Goats and sheep have an increased frequency of short cycling (silent heats) in the middle of the breeding season

A

False- more common at beginning and end, as well as postpartum
-more commonly seen in goats than sheep
-influenced by photoperiod or nutrition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the theory behind why small ruminants have the short cycle?

A

Thought to synchronize the group and bring them all into heat around the same time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How many follicular waves do sheep tend to have during each cycle?

A

3-4, compared to the 2-3 in cattle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How long after the LH surge does ovulation occur in small ruminants?

A

20-26 hours after LH surge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are some of the estrus signs in small ruminants?

A

Swollen vulva, mucoid discharge turning cloudy, tail flagging, mounting/immobilization reflex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are some of the indications for estrous cycle manipulation in small ruminants?

A

-induction of estrus in transition periods and during winter anestrous
-allows for distribution of milk and meat production throughout the year (breed selection is important)
-allows for synchronization within the season (labor saving for breeding and kidding)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are some of the ways the estrous cycle can be manipulated in small ruminants?

A

-adapted nutrition
-photoperiod manipulation (artificial lighting, melatonin implants)
-hormonal treatments (most drugs are not approved for use in the US on goats)
-male effect
-combo of all of these

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the male effect.

A

After 30 days of no contact with the male he is reintroduced which will induce a silent heat and a visible heat during the next cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How can you manipulate the cyclicity of sheep during the breeding season? during the transitional season? Out of breeding?

A

Breeding season: Prostaglandins or progestin source for 14 days (CIDR)+/- gonadotropin (GnRH agonist)
Transitional season: Ram effect, progestin source for 8-14 days + gonadotropin up to 48 hours before removal, progestin source for 8-14 days + ram effect at removal
Out of season: progestin source for 8-14 days + gonadotropin up to 48 hours before removal, manipulation of lights, melatonin administration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How can adapted nutrition aid in fertility of female small ruminants?

A

Flushing females before breeding increases nutrition, which can increase ovulation rate and lambing/kidding rate
-affected by age, body condition, time of year
-best response with marginal body condition (2.5-3/5)
-supplement with 0.14-0.45 kg og a 10-12% crude protein grain/head per day starting 2 weeks pre breeding until 2-3 weeks into breeding season

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What body condition should male small ruminants be when entering breeding season?

A

3-4/5
- will lose 10-12% of condition during season
-should feed concentrated energy protein supplement 4-6 weeks before breeding
-may need to supplement with concentrate to help them regain condition after breeding season
-DO NOT OVERCONDITION- negative effects on semen quality

20
Q

How can you manipulate daylight to encourage cycling?

A

Begin with long days to prepare for the stimulatory effect of short days (if trying to
- decreasing daylight will trigger melatonin release from pineal gland
-could try melatonin implants but these are unavailable in US

21
Q

Describe some of the out of season synchronization protocols for sheep/goats

A

-progestins for >14 days plus PG600 the day of or 24-48 hours before progestin removal
-artificial lighting programs (mimic long days for 60 days followed by short days for 60 days)

21
Q

Describe the hormone treatments that can be used in small ruminants

A

-Prostaglandins lyse the CL. Can do single injections or double 11-12 days apart. Initiates estrus in 24-72 hours. MUST BE CYCLING
-Progestins: mimics luteal phase. estrus shown 24-96 hours after withdrawal
-eCG/PMSG- FSH like activity, acts directly on the ovary to stimulate ovulation
-GnRH agonists: act on the anterior pituitary to stimulate LH/FSH activity

21
Q

For natural breeding, what should the ram to ewe ratio be?

A

A ram per 30-50 ewes
-if really good libido and testicular size + semen characteristics, can breed 100 in 17 days
-ram lambs should only be expected to service 15-25
-lower numbers when out in range pasture
-with synchronized cycles, add a second male as they all will be in estrus at the same time

22
Q

Describe some different options for producing teaser males

A

-teaser harness that blocks off prepuce, but still has marker for breeding detection (there is a risk of them getting it off)
-vasectomy or epididectomy- retains sexual behavior but there is a risk of venereal disease transmission

23
Q

T/F: exposure to seminal plasma via copulation may improve AI rates

A

True!

24
Q

In natural breeding, where is semen deposited?

A

Usually in the vagina
- a lot of the semen dies before it can reach the ovum

25
Q

In which species- sheep or goats- can you inject frozen semen through the cervix?

A

GOATS

26
Q

What are some of the advantages of laparoscopic AI?

A

Higher rates of successful pregnancy, less semen needed

27
Q

When is transcervical AI okay to perform in sheep?

A

When using fresh semen

28
Q

In what part of the horn should you deposit semen when doing laparoscopic AI?

A

In greater curvature where there are no blood vessels
- deposit 50% in each horn

29
Q

What is the normal gestation length in sheep vs goats?

A

Sheep: 145-150 days
Goats: 147-155 days

30
Q

Describe the timeline of pregnancy in sheep and goats?

A

Day 4- embryo enters uterus
Days 12-13: maternal recognition of pregnancy via interferon tau production
Day 16: implantation
Day 20: amnionic vesicle extends to contralateral uterine horn

31
Q

What is the difference between maintenance of pregnancy in sheep and goats?

A

60-75 days: placental progestins take over and CL is no longer the primary P4 source IN SHEEP

IN GOATS CL IS ALWAYS THE PRIMARY PROGESTERONE SOURCE

32
Q

Why do we perform pregnancy detection?

A

To determine if breeding was successful
- to determine if there is infertility issues, to rule out health problems, and make culling decisions
-to determine quantity (those with more babes are more susceptible to preg tox, singletons more prone to dystocia, important for nutritional management decisions)

33
Q

If you are using serum progesterone for pregnancy detection, when should you pull the sample?

A

19-24 days
-not practical in most situations

34
Q

What is a good blood test to use to detect pregnancy?

A

Pregnancy specific protein B
-can detect after 25 days
-cannot determine fetal viability

35
Q

Whats the earliest you can detect pregnancy via ultrasound?

A

25 days with rectal probe
35 days with transabdominal probe

36
Q

When can fetal sexing be done?

A

55-70 days
- more accurate with singletons, hard to do with multiples

37
Q

When can radiography be used for preg detection?

A

after day 70
-accurate but pricey and annoying to set up

38
Q

T/F: fluid in the uterus is diagnostic for pregnancy in small ruminants

A

False- you need to see at least a fetus or a placentome
- they can get hydrometra commonly

39
Q

What is detectable on ultrasound on day 21? Day 25-35? Days 30-40? Days 40-90? After day 90?

A

21: placentomes visible as small echogenic areas on the surface of the endometrium (transrectal)

25-35: embryo readily visible. Hyperechoic fetus in fluid filled uterine horn. Amnion has a hyperechoic line that encircles the embryo at a distance of 1-2 mm

30-40: “C” shaped placentomes become visible

40-90: placentomes, umbilical cord readily visible. Hyperochoic fetuses surrounded by large amounts of hypoechoic fluid. Fetal organs/skeletal structures can be seen. After day 50 fetus starts to resemble a lamb/kid

90+: becomes difficult to count fetuses. Fetal body parts only partially visible but can still view placentomes. Ballotment useful at this stage. Can assess fetal heartrate.

40
Q

How can you age fetuses via ultrasound?

A

-in the first 3 months, fetal size is not related to litter size and head diameters and length provide a good index of fetal development
-by third trimester not accurate as depends on amount of fetuses

41
Q

What are some main considerations for repro management in small ruminants?

A

Know the breeding dates or mating periods to improve the accuracy of diagnosis
-speed and accuracy is important (can change technique, position of animal to improve. Fast from food for 12 hrs and water for 4 hours)
-assess the number and viability of fetuses optimally between 45-85 days

42
Q

If the producers goal is simply to know if they are pregnant, when should you come out to assess the herd?

A

Wait 40 days after the ram/buck has been removed or after the last possible date of breeding
-this allows for balance between speed and sensitivity (while pregnancy can be confirmed in seconds, the diagnosis of pregnant/open takes up to a minute)
-makes it much easier to determine they are not pregnant

43
Q

If the producers goal is to estimate gestational age or number of fetuses, when should you come out?

A

Wait 50-55 days after the ewes/does were first exposed to the ram/buck
-fetuses can be accurately counted until 90 days gestation, but counting fetuses is much faster and more accurate in early gestation
-this may mean more than one exam may be needed

44
Q

What are some important considerations for late gestation nutrition in small ruminants?

A

-realize that 70% of fetal growth occurs in the last 6 weeks of pregnancy
-inadequate nutrition may increase periparturient diseases, cause low colostrum quality, low birth rates, lower energy reserves in newborns and increased death losses
-increase concentrate feeding in last 6 weeks due to increased metabolic demand and lower abdominal space

Food Animal Therio (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions