Managing fertility and manipulating the breeding season workshop Flashcards
What are the reproductive aims of pigs
aim to produce > 20 live piglets each year (≥ 2 litters
what are the reproductive aims for sheep
aim to produce 1-2 lambs each year- depends on upland/lowland
what are the reproductive aims for cows
aim to produce one live calf once a year
What is the target scanning percentages for upland/lowland/hill sheep farming
upland= 200%
lowland= 175%
hill= 115%
what is the target abortion rate in sheep/ cattle
<2%
List 7 factors that can cause failure to breed in ewes
Body condition score
General health
Stage in annual cycle
Season
Anatomical/congenital abnormalities
Errors in synch protocols
Ram problems
List 5 factors that can cause failure to breed in rams
Low/absent libido
Pathologies of the penis/prepuce affecting intromission
Lameness
Inexperience
Too high ewe:ram ratio
List 4 factors that can cause failure to conceive in rams
Pathologies causing orchitis/epididymitis
Penile abnormalities
Inadequate testicular circumference
Sperm abnormalities
what is the target calving interval
herd average of 365days
decribe how to calculate the barren cow rate and what is the target
Number of non-pregnant cows ÷ number of cows bred x 100
<5%
Describe how to work out calving pattern
When calculating % calved in 1st 3 weeks, include all cows calving prematurely as well as those actually calving in the 1st 3 week window
How is heifer submission rate calculated and the target for this
Heifers bred ÷ heifers eligible to be bred x 100
>80%
At what age/ weight do you want to serve dairy heifers
13.5months
397kg
How do you work out fertility efficiency and the target for this in all year round herd
Conception rate x submission rate
>25%
List 6 potential factors that can cause failure to conceive in cows
Body condition score
General health
Milk yield (dairy)
Anatomical/congenital abnormalities
Errors in synch protocols
Bull problems
List 4 potential factors that can cause Failure to conceive/maintain pregnancy in cows
Reproductive pathology
Early embryonic death / abortion
Errors in synch protocols
AI errors AI commonly used in dairy herds
List 3 ways that increased yeilds has resulted in decreased fertility in dairy cows
Problems with postpartum resumption of cyclicity
Reduced oestrus behaviour
Oocyte and embryo quality
To acheive 365 calving interval when do dairy cows need to conceive
need to start breeding before 58 DIM
conceive before 84DIM
List 3 ways NEB after calving can reduce fertility
adverse effects on resumption of cyclicity
reduced embryo quality
associated with increased risk of postpartum disease
why do high yeilding cows have shorter oestrus
have lower oestradiol concentration
due to increased metabolism of the oestradiol and decreased production of the oestradiol if animal is stressed
why may we manipulate the breeding season in lambs
Aim to breed as early as possible to maximise breeding opportunities and capitalise on higher lamb prices in Spring
what makes up ‘cows that are eligible for breeding’
Those outwith the voluntary waiting period
Those that are not pregnant
Can hormones be used to improve submission rate in dairy
Yes
Can do:
- synchro protocols and fixed time AI- submission rate should be 100% not always effective
- synchro protocols and AI to observed oestrus
after giving PGF2a to cow with mature CL when will the cow come into oestrus
in 3-5 days time
How can we manipulate the cow oestrus cycle to shorten breeding season
Synchronise cows so more of them come into oestrus in the first 6 weeks
which synchronisation protocol has the best conception rate
one which includes progesterone
what is the most common cause of anoestrus in beef herds- how to treat
suckling calves present- causes reduced LH pulse
CIDR/ PRID- synch
List 3 ways to advance the breeding season in sheep
Ram effect
Melatonin implant
Progesterone (or synthetic progestogen) + equine Chorionic Gonadotrophin (eCG)*
how does ram effect work
Entire or vasectomised ram presence –> stimulates ovulation
advances breeding season by 2weeks
Much much can a melatonin implant advance the breeding season
brings forward by up to 2 months
how do melatonin implants work in sheep
Melatonin implant mimics effect of shortening photoperiod
GnRH is produced by hypothalamus at an earlier point in the year
Describe how to implant melatonin implant
Day 1= 30 weeks before desired start of lambing - remove all rams from sight or smell of ewes
Day 7= implant ewes
Day 42= 35 days after implantation- introduce rams
Peak mating activity occurs about 25 days after ram introduction
By how much does progesterone devices and eCG advance the breeding season in sheep
by 4-6 weeks
what is an advantage of progesterone devices on advancing sheep breeding seasons
Suitable for cycling and non-cycling ewes
- Non-cycling –> eCG is needed otherwise results are poor
- Cycling –> eCG is optional but synchronisation is optimised if used
