Lecture 3 Flashcards
What is included in the replacement or terminal index? list them: 14
-Days to slaughter
-Carcase conformation
-Carcase fat
-Maternal days to slaughter
-Maternal carcass conformation
-Maternal carcase fat
-Ewe mature weight
-Maternal lamb survival
-Maternal single lambing ease
-NLB
-Single lambing ease
-Multiple lambing ease
-Lamb survival
What is the maternal weight:
What is the economic value per kg?
What is the replacement %?
€0.36
15.93%
What are the advantages of increased ewe size?
-Lamb with superior growth rate
-Increased milking ability and prolificacy in some breeds, subject to adequate nutrition
-Increased cull ewe value
-Potential to increase breeding stock value, where larger ewes are in demand
What are the disadvantages of increased ewe size? (5)
-Increased feed requirements
-Poor performance in a harsh environment
-Increased capacity required for housing
-Heavier, stringer sheep to catch and handle regularly
-Lower stocking density
What are the main reasons to cull? (7)
- Teeth, not age
- Mastitis – no brainer
- Barrenness ??? – data/cost/id - repeatability low
in young ewes - Prolapse – data/id
- Thin ewes – BCS and data
- Severe foot problems – data/id
- Production – data on lamb performance
Whats the average age to cull?
4.7
From year 1-4 what does ewes teeth look like?
1-1.5- Incisor 1.1 eruption
1.5-2- Incisor 1.2 eruption
2.5-3- Incisor 1.3 eruption
3.5-4- Incisor 1.4 eruption
Effects of Age on progeny performance:
As the ewe gets older, the litter size decreases, the Number weaned decreases, the Weight of lamb at birth increases, the weaning weight decreases, the growth rate decreases and lamb mortality % decreases
What are the options for breeding ewe lambs?
– Purchase hoggets at 18 months
– Rear or purchase ewe lambs, carry dry over the
first winter and breed as hoggets
– Breed ewe lambs in their first season
Other option
– Purchase ewes with lambs at foot
* Pro’s and con’s
What is the cost associated with rearing a ewe replacement to joining the flock for mating at 18 months?
Costs: -ewe lamb 95€
forage 46€
vet€4.4
shearing€2.5
housing€18
mortality€4
miscellanous€2.4
total costs€172.8
What is the sales from rearing a ewe replacement?
wool €3
cull carcass value€43.3
total sales€46.4
What is the net cost of rearing a replacement ewe?
€126.4
Whats the purchase value for a hogget?
Whate the ewe lamb value of a dry hogget?
Whats the ewe lamb value of a ewe lamb mated?
€190
€95
€115
What is the annual replacement cost / mature ewe of a:
-Hogget Purchased
-Dry Hogget
-Ewe lamb mated
-Hogget Purchased= €22
-Dry Hogget= €13.75
-Ewe lamb mated= €8
Age of lambing statistics:
-12 months
-24 months
-12 and 24 months
(slide 14)
-12 months = 53%
-24 months = 45%
-12 and 24 months = 2%
What type of breeders are sheep?
Seasonal breeders
List long season breeders: (6)
6-8 months
Finn
Romanov
Rideau
Rambouillet
Polypay
List medium season breeders: (5)
4-6 months
Suffolk
Hampshire
Oxford
Canadian
Charolais
List short season breeders (5)
North Country Cheviot
Leicester
Scottish Blackface
Texel
Shetland
Reproductive Characteristics of Ewes:
1- Age at puberty
2- Oestrus cycle length
3- Oestrus duration
4- CL Life span
5- Fertilizable life of ova
6- Gestation length
1- Age at puberty: 6-9 months (season and weight dependent)
2- Oestrus cycle length: 17 days (14-19)
3- Oestrus duration: 24-36 hours
4- CL Life span: 14 days
5- Fertilizable life of ova: 10-25 hours
6- Gestation length: 147 days (144-153)
Slide 18 Days of Oestrous Cycle :
When is the luteal phase?
When is the follicular phase?
When is the luteal phase?
When is the luteal phase?- 10-13
When is the follicular phase?- 14-16
When is the luteal phase?- 0-9
When does luteclysis occur?
When does oestrous occur?
When does ovulation occur?
When does luteclysis occur?- 14-15
When does oestrous occur?- 0
When does ovulation occur?- 1
How do you measure performance? (2)
- Lambing percentage:
= (no of lambs born/no of ewes to ram)*100
- Weaning percentage:
= (no of lambs reared/no of ewes to ram)*100
Whats the average BCS of the flock?
2.5-3.5
But mostly 3.5
The effect of BCS on lambing outcome
(Crosby) of a ewe is 3.5 how many live lambs will be born? how many spread of lambing days ?
161
43
The effect of BCS on lambing outcome
(Crosby) of a ewe is 2.5 how many live lambs will be born? how many spread of lambing days ?
130
70
What % of farmers BCS their ewes?
59%
What % of farmers select rams on genetic indexes?
61%
What % of farmers raddling rams at mating?
61%
What % of farmers pregnancy scan their ewes?
82%
What % of farmers weight their sheep ?
70%
What % of farmers faecal sample their sheep?
56%
What % of farmers Grass measure ?
11%
What % of farmers make silage/hay?
35%
What % of farmers soil test?
77%
What % of farmers complete profit monitor ?
48%
What % of farmers have a handling unit?
54%
When BCS ewes, what are the 4 things to take into account?
- No specialised equipment required
- Independent of between breed differences in
skeletal size - Physiological state
- Fleece length or wetness
What is the target BCS?
-8 weeks before mating
-At mating
-Lambing
-Weaning
-8 weeks before mating: 2.5 minimum
-At mating: 3-3.5
(ram 3.5-4 at mating)
-Lambing : 3-3.25
-Weaning: 2-2.5
Gaining 1 BCS is equivalent to :
an energy gain
of 24 MJ/kg live weight
Energy used with about ?% efficiency
45%
Ewe requires ?MJ per kg gain
55MJ per kg gain
If aiming for 10kg LW gain this equates to:
550MJ energy
What does a score 1 of a BCS feel like?
The vertical and horizontal processes are
prominent and sharp. The fingers can be
pushed easily below the transverse and each
process can be felt. The loin is thin with no fat
cover.
What does score 2 feel like?
The vertical processes are prominent but
smooth; individual processes being felt only as
corrugations. The horizontal processes are
smooth and rounded, but it is still possible to
press fingers under. The loin muscle is
moderate in depth but with very little fat
cover.
What does score 3 feel like?
The vertical processes are smooth and
rounded; the bone is only felt with pressure.
The horizontal processes are also smooth and
well covered; hard pressure is required with
the fingers to find the ends. The loin muscle is
full and with a moderate fat cover.
What does score 4 feel like?
The vertical processes are only detectable as a
line. The ends of the horizontal processes
cannot be felt. The loin muscles are full and
rounded, and have a thick covering of fat.
What does score 5 feel like?
The vertical and transverse processes cannot
be detected even with pressure; there is a
dimple in the fat layers where the processes
should be. The loin muscles are very full and
covered with very thick fat.
What is flushing?
Increasing plane of nutrition to ensure weight
and condition score gain prior to breeding
Explain the process of flushing. (4)
- Increasing the plane of nutrition (energy
intake) prior to breeding
– 6-8 weeks - Better response early in the breeding season
- Better response with mature rather than
young ewes - Better response with ewes with a low starting
BCS
Flushing and Body Condition:
1- BCS at mating=
2- How many weeks on good grass = 1 unit of body condition?
3- What should you avoid before flushing?
4- When should flushing be continued until?
1- Body score 3-3.5 at mating
2- 6-10 wks on good grass= 1 unit of body
condition
3- Avoid over-starving before flushing and have
ewes increasing in weight
4- Avoid stress and continue flushing for 1st month
of pregnancy
How does flushing work? 4 points
- Increases the numbers of eggs ovulated
- Improve LH surges- required for ovulation
- Increased nutrition – increases insulin
production– increases glucose uptake –
increases oocyte growth - Hepatic steroid metabolising enzymes are
increased thus clearing steroids with an
associated increase in gonadotrophin
If there is a negative energy balance, what effects can it have on reproduction?
-Anovulation
-Anoestrus
If there is an energy balance, what effects can it have on reproduction?
Ovulation rate below natural maximum
If there is a positive energy balance, what effects can it have on reproduction?
Maximum natural ovulation
Slide 41 havent a clue
Mineral nutrition at mating: 4
- Selenium
- Cobalt
- Copper
- Iodine
– All implicated to varying extents in reproductive
failure, embryonic death, low litter size
Synchronised lambing
explain ‘The Ram Effect’
- Week – 6: isolate ewes from rams
- Day 0: introduce vasectomised rams
- Day 2: remove vasectomised rams
- Day 3-4: Silent heat (2nd silent heat 6
days later in portion of the flock) - Day 14: introduce fertile rams
- Day 18: normal heat peak 1
- Day 26: normal heat peak 2
- Day 35-43: repeat cycle
Sponging to synchronise
oestrus/lambing
Day 0AM- insert sponges
Day 12AM- Remove sponges and inject PMSG (500-750IU)
Day 13PM- Mating Hogget ewes
Day 14AM- Mating mature ewes
Day 16- Remove Rams
Day 28- Introduce Rams for repeat mating
Day 34- Remove Rams
Day 80- Scan Ewes and return non pregnant ewes to ram
Early pregnancy situation:
Ovulation: 12 hours after Oestrus; Fertilisation, up to 24 hours alter; implantation
does not occur for another 15 days
Ram management :
Week 10 prior to tupping:
Week 7 prior to tupping
In the first 3 weeks of tubbing what happens?
When are most ewes served?
Examine rams 10 weeks before tupping start feeding protein supplement.
Testicles should be large and firm 7 weeks before tupping
Semen used to fertilise the ewes served in the first three weeks of tupping is produced here
Most ewes are served during the first 3 weeks of tupping
So from 10 weeks to week 0 you need to feed rams high quality bypass protein supplement
From week 0-6 you the ram is with the ewes
What BCS should a ram be?
How much body weight can a ram lose in a 6 week season?
What will reduce mating activity?
- BCS 3.5-4: fit not fat. Can lose 15% of body
weight in a 6 week season - Feet: no lameness or infection. Can reduce
function and also breeding for lameness - Brisket sores/ lesions: Will reduce mating
activity
What should the Scrotum/testicles be like of a ram?
x2, descended, firm, free of
hard lumps. Large testicles produce 80% more
semen than medium sized testicles
Flock life of a ram:
As the ram gets older from 1 year old to 4 years old the ram decreases in value anywhere from €7.50/3.00-€1.88/0.75
What should the ratio be of a ram in a flock?
25/30:1
Never depend on one ram for a flock!
Shearling ratio in a flock:
50/60: 1
2 shear (3 year old) in a flock?
up to 80
Sponging in a flock ratio:
8-10: 1
What is the practice:
40 ewes/ ram or 3 rams for the average flock
In NZ how many ewes per ram?
up to 150 ewes per mature ram
Time of mating:
- Early Lamb
(a) Relate lambing time to the time of Easter.
If Easter is early lamb before Christmas (unless concentrate fed).
If Easter late, lamb after Christmas.
(b) Lambing to mean sale date is about 16 weeks
(c) Avoid lambing Christmas day»_space; mate after August 5th. - March Lambing
Lambing 10-20 March. Rams joined in mid-October
– earlier in South and later in North - Hill/Mountain Systems
Mating in Nov. Lambing in April (when herbage growing)
Raddling/Keeling
1. Why use some form of marker at mating ?
– infertile ewes
– infertile rams
– estimate lambing time/date
Raddling methods: (5)
– crayon – soft/hard»_space; use proper kind
– colours yellow/green/red/blue/black
– raddle powder
– raddle harness
– rub-on crayon
How often should you change colour for raddling/keeling?
Use some form of marker and change colour every 15-17 days
What are the Raddling – Economic Advantages
- High quality hay/silage fed Concentrates: 0.1 - 0.7 kg in last 7 wks
- Lambing spread 6 weeks Concentrate cost: €380/t
FEED SAVING DUE TO SPONGING & RAM RADDLING €3.72/ewe
*Colour change every ?? days;
??% lambed in first 2 wks;
??% in next 2 wks;
??% lamb in first 3 weeks
14 days
50%
30%
65%
Savings are greater where:
- (a) Roughage quality poorer;
(b) Lambing longer than 6 weeks
(c) Higher concentrate prices
(d) Thin ewes
Raddling – Economic Advantages (4)
- Economise on feed costs, especially concentrate
supplementation - Saving greater with poor quality forage, higher
concentrate costs, long feeding period - More efficient planning of whole system
– Housing !
– Winter shearing ! - Batch ewes according to lambing date
What % of farmers raddle rams at mating?
61%
