Repro

Question 1

Are heterozygotes or homozygotes more fertile?

Answer 1

Heterozygotes

Homozygotes less fertile or infertile

Question 2

Name 3 repro conditions overweight ewes may be prone to

Answer 2

Dystocia
Pregnancy toxaemia
Prolapse

Question 3

How is AI done in sheep?

Answer 3

Via laparoscope (due to cervix)

Question 4

When manipulating seasonality in sheep, you can give Regulin. What is this and after how long should you introduce the ram?

Answer 4

Melatonin implant in ear

Introduce ram after 1 month

Question 5

What is chronogest? How long is it intravaginal for and when should tupping occur?

Answer 5

Synthetic progesterone sponge
Intravaginal for 12-14 days
Tupping 48 hours after removal

Question 6

Prostaglandin is not authorised in sheep for oestrus manipulation, but may be used. How many days apart should the injections be and when does oestrus occur?

Answer 6

2 injections 7-11 days apart

Oestrus occurs within 40 hours

Question 7

Which drug can induce lambing and from how many days pregnancy?

Answer 7

Dexamethasone

140d + (last 2 weeks)

Question 8

Is dexamethasone licensed to induce parturition in sheep? When can it be used?

Answer 8

No

Can only be used if service date know

Question 9

When can scanning for PD occur in ewes?

Answer 9

70-120d after ram in

Or 28d after ram out

Question 10

How does BCS and liveweight affect ovulation rate? (‘the static and dynamic effect’)

Answer 10

Higher BCS and higher liveweight = higher ovulation rate

Question 11

What BCS should a ram be prior to tupping season?

Answer 11

3.5+

Question 12

What scrotal circumference should a ram have prior to tupping?

Answer 12

30cm

Question 13

What is Pizzle rot and what pathogen causes it?

Answer 13

Balanoposthitis - inflm of penis and prepuce
Due to urination inside prepuce
Corynebacterium renale

Question 14

What is the biggest risk factor for developing Pizzle rot/balanoposthitis?

Answer 14

Castration at young age

Question 15

Balanoposthitis/pizzle rot may cause ulcers, discharge, scabbig and blockage or even flystrike. Name some risk factors for this condition

Answer 15

Castration at a young age!!!
High protein concentration diet
Lush grass
Acidic urine - access to water, salt or ammonium chloride

Question 16

What is the treatment for balanoposthitis/pizzle rot?

Answer 16

Isolate
Clean and clip
Systemic ABs
+/- fly treatment

Question 17

What is a ‘rig’? Can they be used?

Answer 17

Cryptorchid ram

May be less fertile - put with fewer ewes or castrate - hereditary?

Question 18

Inguinal hernias in rams are usually unilateral. How are they treated?

Answer 18

Surgical repair and castration (hereditary)

Question 19

What mite causes scrotal mange? Where else may it occur?

Answer 19

Chorioptes bovis

Lower leggs and poll

Question 20

Does Chorioptes (scrotal mange) affect fertility?

Answer 20

Yes if extensive

Question 21

How is scrotal mange/Chorioptes diagnosed and treated?

Answer 21

Dx: skin scrape
Tx: doramectin (longer lasting than ivermectin) or diazinon

Question 22

What triggers testicular degeneration in sheep?

Answer 22

Stress
Inflammation
High BCS
High temperature

Question 23

Is testicular degeneration permanent?

Answer 23

No - causes poor fertility in first year

Return to soundness in 3 months as new sperm develop

Question 24

How long does spermatogenesis take in a ram?

Answer 24

49 days

Question 25

What is the average ewe cycle length?

Answer 25

17 days

Question 26

Give 2 examples of what may cause testicular hypoplasia

Answer 26

Cryptorchidism

Hereditary disorder - XXY chromosome

Question 27

What are the 3 most common abortive agents in sheep?

Answer 27

Chlamydophila abortus
Toxoplasmosis
Campylobacter