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Definition
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Term
| length of follicular phase |
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Definition
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Term
| Preparing flocks for breeding |
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Definition
- ensure ewes and tups in good body condition ready for tupping
- sort ewes at weaning- decide on culling policy- bad teeth, bad udder health, bad feet
- examine rams several weeks before tupping- full MOT
- supplementary feed tups if needed
- put poorly conditioned ewes on best pasture and supplementary feed if needed- flushing
- ensure adequate replacement ewes and rams in place
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Term
| closed policy for replacements |
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Definition
own bred ewes: decreased risk of disease introduction, increased prevalence of proven heritable traits, good record keeping needed
Rams from accredited flocks: must quarantine- worms, sheep scab, foot rot |
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| open policy for replacements |
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Definition
- increased risk of disease
- must quarantine
- but can buy in genetic potential
- greater choice |
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Term
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Definition
– 70% of 70Kg = 49Kg (breed dependent)
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– Weight at birth approx. 4Kg (breed dependent)
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– Average age at tupping = 7 months (210 days)
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– 45Kg / 210 days ~ 214g / day from birth
• Good management needed
Wean lambs from ewe lambs early to ewe lambs to recover from 1st lambing
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Term
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Definition
- MOT rams
– Bodyconditionscore
– Teeth
– Feet
– Eyes
– Fertility examination?
Supplementary feeding
– BCS3.5-4atmating
– 18-20%proteinration
• No magnesium
• Beware of urolithiasis and pizzle rot
Ram to ewe ratios:
– Adults=1:40-60 – Ramlambs=1:30
Raddle rams to monitor
ewe service / return to service
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Term
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Definition
- benefits ewes in BCS 2.5-3
- increased ovulation rate
- rising nutrition 3 weeks prior to tupping
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Term
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Definition
| - lowered ovulation rate possible |
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Term
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Definition
Why?
– Synchronisation
• Better labour management around lambing
• Easier flock health management
• Consistent lambs for sale
• Enables use of AI
– Improved genetics
– Advance breeding season • Lambs ready for sale earlier
(meat or replacement stock)
• Can allow two lambing groups
– early pedigree, later commercials?)
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Term
| Breeding season of the ewe |
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Definition
- sheep are seasonal breeders
anoestrum Dec-June
Transition June -Sept
Breeding Sept -DeC |
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Term
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Definition
16-17 days long
- 3-4 day follicular phase: LH surge, oestrus behaviour, ovulation at end of period
- 13-14 day luteal phase: regresses if no pregnancy |
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Term
| How to manipulate breeding |
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Definition
- ram or teaser effect
- progestagen sponges
- melatonin implants |
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Term
| Vasectomised ( teaser ) rams |
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Definition
Why?
– Advance breeding season by a fewweeks
– Helps synchronise oestrus
• How?
– Easy surgery done inpractice
• Well in advance of breeding season
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– No ram to ewe contact for several weeks
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– Additionofvasectomisedram->ovulation
• 1 vasectomised ram : 50 - 100 ewes
• Silent heat in ewes (24-48h)
• OR early CL regression then silent oestrus (~ 7d) – Oestrus at 18-20 days or 24-28 days
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– Remove teasers after 7days
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– Introduce fertile rams after another week
• 1 ram : 25-30 ewes
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– Two peaks of oestrus in 10 days
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– Lambingover~21⁄2weeks
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Term
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Definition
Chrongest®
– To synchronise ewes
– To advance breeding season: + PMSG • May only ovulate once following removal.
– Day 0: Insert sponge
– Day 12-14: Remove sponge
– 36-40 hours later: Add fertile rams • Not before as will exhaust rams
– Remove rams > 48 hours later
– 16 days after sponge withdrawl: Put raddled rams back out
– Monitor returns
- For AI must use PMSG- different aounts by breed and by amount of advancement of breeding season
AT LAMBING: 1st servie ewes- lamb in 1st week
no lambs in week two
- raddle ewes- lamb ing 3rd week
- 75% conception expected from 2 services
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Term
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Definition
- melatonin increases within increasing darkness
- implant mimics this- 2 month advancement
- regulin ear implant
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Day 1 (10 weeks before desired lambing start) - remove all rams from sight or smell of the ewes
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Day 7 - implant ewes
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Day 42 (35 days after implantation) - introduce rams
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Day 65-70 ish: Peak mating activity
– will occur about 25 days after ram introduction – Monitor service using raddle
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Suffolks and Dorset horns respond well
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Ewes feeding needs care
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Term
| When is abortion a problem |
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Definition
Target <2%- sporadic, non preventable
>2%- possibly infectious
make sure it is an abortion problem and not poor tupping to scanning |
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Term
| protection in the face of abortion |
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Definition
1. isolation and reduce stocking density
2. strict personal hygiene zoonoses
3. Careful disposal, incineration best practice
4. care on submission of biological material
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Term
| Investigate an abortion case |
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Definition
history: vaccinations, replacement policy/recent purchases, tupping/scanning records
- examine aborted ewes
- examine any live lambs
- collect and examine aborted material
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Term
| submission of samples to VI lab |
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Definition
- carefully packaged
- foetus and placenta ( complete with cotyledons)
- fresh as possible without contamination
- vaginal swabs and or blood samples from the aborting ewes if no abortion products
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Term
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Definition
Chlamydophila abortus – Enzootic abortionToxoplasma gondii – ToxoplasmosisSalmonella spp.
Campylobacter fetus fetus (intestinalis)
Border diseaseListeriosis
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Term
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Definition
- conflicting opinions as to length of time to leave sponges inserted
- suggest left in for 18-21 days |
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Term
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Definition
secreted by pineal gland during hours of darkness -> increasing amounts in repsonse to increasing hours of darkness
longer nights-> increased melatonin -> hypothalamic release of GNrh -> LH and FSH-> oestrus and ovulation |
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Term
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Definition
- can be used to synchronise groups of sexually active ewes,
The CL is responsive to PG from approx. days 4-14 of the cycle, similar to cattle. There is debate regarding the interval between injections of PG, but intervals of between 9 and 15 days are recorded. Oestrus occurs approx. 40 hours after PG with ovulation 30 hours later. Doses of 250ug cloprostenol (1ml Estrumate®) appear to be the most effective although the results are so much more variable than 'sponging' that it is unlikely this technique will become widely used.
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Term
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Definition
- often not practical technique as mating dates are seldom known and risk of reduced lamb survival is great if excessive prematurity
- Ewes: 16mg betamethasone (short acting) given i/m will induce lambing in 26- 60 hours in most cases
o Does: 150ug of synthetic PGF2α, cloprostenol (Estrumate®) given i/m is effective in inducing parturition in does, as maintenance of pregnancy is dependant on progesterone secretion from the CL. OR 16mg of betamethasone/dexamethasone may be used as for ewes
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Term
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Definition
Farmers sometimes request misalliance injections, for example in ewe lambs. Prostaglandins are only effective at specific times during gestation in the ewe (prior to maintenance by the uterus) and therefore must be used carefully and with proper explanation of the risk of failure. Has been shown to be effective between 20 and 60 days of gestation (Tyrrell et al. 1981). Up to 10mg may be needed when 2 CL are present (4ml of Estrumate) (Silvia & Niswender 1984).
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