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Ovine Flashcards

1
Q

When does puberty occur?

A

6-9 months at 60% of mature bodyweight

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2
Q

Describe the placenta

A

Caruncles and cotyledons - epitheliochorial

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3
Q

Name the 6 types of cervix

A 
Duck bill 
Slit
Rose
Papilla
Flap 
Spiral
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4
Q

Name the 4 types of AI

A
  1. Shot in the dark
  2. Intracervical
  3. Laproscopic (intrauterine)
  4. Over the rail
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5
Q

What types of breeders are sheep?

A

Short day

Seasonally polyoestrus

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6
Q

How long is the oestrus cycle?

A

14-19 (16) days

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7
Q

How long is oestrus?

A

24 hours average - shorter in maidens and longer in older years

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8
Q

When does ovulation occur?

A

24-30 horus after onset of oestrus (the end)

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9
Q

How long is the luteal phase?

A

13d

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10
Q

How many follicular waves per cycle?

A

3-4 per cycle

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11
Q

Oestrus behaviour examples

A

Seeking service
Stands for mounting
Sexually active groups seek the ram not other females

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12
Q

What is the gestation length in sheep?

A

145-150 days

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13
Q

When is IFN tau released?

A

Before 14 days - prevents PGF2a

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14
Q

When is the CL responsive?

A

50 days - only present for this long in the sheep (PGF2a use in sheep before this can abort pregnancy)

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15
Q

Name 2 substances released during maternal recognition of pregnancy and how do they do cause MRP?

A
  1. IFN tau (trophoblast)
  2. Ovine trophoblastic protein

Inhibit expression of oxytocin receptors -> no PGF2a -> CL remains

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16
Q

When can we diagnose pregnancy with ultrasound?

A

reliably >40d gestation

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17
Q

Where does pregnancy specific protein B come from and when?

A

Comes from binucleate giant cells in placenta

Can identify this from 14 days

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18
Q

What is the ratio for adult paddock matings?

A

1:50

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19
Q

What is the ratio for synchronised females in season?

A

1:10

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20
Q

What is the purpose of CIDR?

A

Produce progesterone and extend luteal phase

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21
Q

What is the purpose of sponges?

A

Progesterone release

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22
Q

How long are sponges or CIDRs inserted for and what is the process after their removal?

A

12-14 days
Inseminate 55 hours after removal

Spring joining -> inject 400IU eCG after removal

Frozen AI -> 400IU eCG and do laproscopic AI 55 hours after removal

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23
Q

Name 2 prostaglandin oestrus synchronisers

A

Lutalyse

Estrumate

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24
Q

What must be present in order for prostaglandin oestrus synchronisers to work?

A

A 5 day CL

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25
What is the process of using Lutalyse and Estrumate?
2 injections 9-12 days apart Oestrus occurs 2-4 days after second injection
26
What is the ram effect and when can it occur?
If ewes isolated for 1 month they respond to ram introduction with LH surge within 48 hours and ovulation 3-5 days after rams put in First ovulation = silent -> will be in standing heat next time
27
When would you breed after using ram effect?
21d after ram introduction | Do remainder 28 days if some were silent
28
Is the ram effect suitable for fixed time AI?
No -> synchrony not right enough | Can use alonside drugs to enhance LH surge (when CIDRs are removed for example)
29
How much does the ram effect advance the season?
3-6 weeks
30
Example Ram Effect schedule
``` Day 0 -> teasers in 3-5 -> silent heat 14 -> teasers out rams in 21 -> early mating group 28 -> late mating group ```
31
How do we prepare teaser rams for the ram effect?
3 injections 2ml testosterone weekly | Last injection when turned in with the ewes
32
what are the conception rates for the shot in the dark method?
50% (vaginal AI)
33
What are the conception rates for over the rail?
65%
34
What are the conception rates for laparoscopy?
65%
35
What difference does increasing the sperm number make if we inseminate deeper than 1cm into the cervix?
3% difference in conception rates between 50 and 400 million sperm -> no point using a larger dose if we inseminate like this
36
If we are using fresh sperm, is there an ideal place to inseminate it?
No - vaginal, cervical and uterine yield the same conception rates with fresh sperm
37
When do rams go through puberty and what are 2 factors that affect this?
6 months -> birth time and breed
38
What age does a buck hit puberty?
3 months
39
What type of scrotum do rams have?
Pendulous
40
What accessory glands do rams have?
All
41
Name 5 factors affecting ram reproductive performace
1. Nutrition 2. Libido 3. Sperm production (scrotal C.) 4. Season effects 5. Reproductive disease
42
What does obesity or anorexia cause in rams?
Loss of libido Reduced sperm production Reduced stamina
43
Which testis is larger in the ram?
The right is larger
44
Name 6 things we look for in scrotal pathology
1. Scabies 2. Photosensitisation 3. Scrotal dermatitis 4. Insect bites 5. Allergic reactions 6. Ectoparasites
45
Name 6 things that would cause us to cull a ram
1. Epididymitis 2. Pizzle rot 3. Penile adhesions 4. Cryptochidism 5. Scrotal abcess 6. Penile deviations
46
Name 2 testicular conditions in the ram
Brucellosis | Epididymitis
47
What is brucellosis and how do we test for it?
A venereal disease causing epididymitis in rams and thick necrotic placentitis in ewes Reduced fertility/sterility Test semen/blood
48
How do we diagnose epididymitis and what is it usually caused by?
Usually brucella ovis or A seminis infection | Palpate testis and epididymis
49
How does brucella ovis infect?
Enters systemic circulation via mucous membranes (vaginal, prepucial or conjunctival)
50
When does seroconversion occur with brucella ovis infection?
1-2 weeks post infection
51
When does shedding of brucella ovis occur in semen?
4-6 weeks post infection
52
List clinical signs in ewes of brucella ovis
Return to oestrus 25-35% abortions in affected flocks Thick necrotic placentitis No permanent infection
53
List 4 clinical signs of brucella ovis in the ram
Enlargement + fibrosis of epididymis Reduced volume of testis Semen culture and serology positive Detached heads on spermiogram
54
How do we control brucella ovis?
palpate + cull vaccinate ELISA
55
Name 5 less common issues causing sub or infertility in the ram
1. Developmental defects (wollfian duct issues) 2. Spermiostasis (blind duct ends) 3. Spermatocoele (cystic dilation of epididymal duct - sperm accumulation) 4. Sperm granuloma - inflammatory reaction to sperm products 5. Spermatic cord issues - abscess, hernia, tortion
56
What is a "good" scrotal circumference rating for an animal <14 months and >14 months old?
<14 months - 36cm | >14 months - 40cm
57
What is the duration of spermatogenesis and epididymal transit time in rams?
49 days | 13-17 days transit
58
What is a ram's daily sperm production?
10 x 10^9
59
What is the ideal volume, motility, morphology and concentration for a ram?
Volume - 0.5-1.5ml Motility - 70-90% Concentration - 2-5 x 10^9/ml Morphology 70-90%
60
What is "satisfactory" motility and morphology for a ram?
>30% motile | >50% morphology
61
what are 3 influences of the ram on the ram effect?
Age Libido depth of anestrum
62
Name 6 factors contributing to reproductive wastage in sheep
1. Ram infertility 2. failure to conceive 3. abortion 4. perinatal mortality 5. ewe mortality 6. embryonic mortality
63
What is the number 1 criteria of reproductive performance?
Lambs weaned per ewe joined
64
Name 5 things to consider in flock history/observation
1. Rams working 2. Concentration of lambing 3. Pasture condition 4. time of joining 5. parasite control
65
4 factors reducing fertility at joining
1. Anoestrus 2. Failure of insemination 3. Low ovulation rates 4. Embryonic mortality
66
How to diagnose anoestrus (3)
1. Ram harnesses should have 70% marked in first 14 days 2. Long lambing season 3. Non-pregnant ewes at lambing
67
5 reasons for failure of fertilisation
1. Joining maidens + adults together 2. Paddock topography (hills) 3. Disease - B. ovis, A. seminis 4. Oestrogenic pastures 5. poor libido - lameness?
68
Signs of failure of fertilisation
1. return to service 2. drawn out lambing 3. poor lambing %
69
Reasons for fertilisation failure with no return to service
Coming into season late in season Lapsing back into anoestrus after ram effect Signs -> poor lambing % with few returns to service
70
When does peak ovulation rate occur?
Autumn
71
What do phytooestrogens do and what produces them?
decrease multiple ovulation | Lucerne and clover pastures
72
What is "flushing" a ewe?
Grazing protein/energy supplements (lupins) that increases ovulation rate before joining
73
5 factors decreasing % lambs at marking
``` Abortion Dystocia Predation Starving, mismothering and exposure (MSE complex) Neonatal infection ```
74
Name 4 bacteria/protozoa causing abortion
1. Campylobacteriosis 2. Listeriosis 3. Chlamydia 4. Streptococcus
75
What does chlamydia do to sheep
Soil borne - get into placental tissues | vaginal and faecal swabs positive
76
When is listeriosis a risk?
on high pH silage
77
How is toxoplasmosis spread in sheep?
Cats are hosts - faeces eaten by ewe resulting in mid-late abortion and placental infection
78
Name 4 viral abortion pathogens
1. Bluetongue 2. Border disease 3. Arboviruses 4. Brucella ovis
79
When does bluetongue cause abortions?
Late gestation
80
When does border disease (similar to pestivirus) cause abortion?
<85 days gestation
81
Name 5 non-infectious causes of abortions
1. Stressors and trauma 2. Hyper/hypothermia 3. protein calorie malnutrition 4. Toxic plants 5. Iodine or selenium deficiency
82
Name 5 causes of dystocia in sheep
1. Hypocalcaemia 2. Postural abnormalities 3. Multiple births 4. Parity (maidens) 5. Fetal anasarca
83
Explain the SME complex
Starvation -> failure to suck (competition, weakness) Mismothering -> multiple births, disturbance, inexperience Exposure -> adverse lambing conditions, extreme temperatures, hypothermia
84
Name causes of neonatal infection
High stocking density Umbilical, oronasal or transplacental infection

Reproduction (9 decks)

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