Oestrus Flashcards
Which ovary do 60% of ruminant ovulations come from?
Right ovary
How many days post-partum is it to visible oestrus for dairy cows and beef cows? When does the silent ovulation occur?
Dairy cows - 25-45
Beef cows - 50-60
Both have silent ovulation at 10-14 days
Give examples of ways oestrus can be detected
Tail chalk and mount detectors Teaser animals Chinballs Record keeping Milk progesterone Pedometers (AM/PM rule -serve 12 hours after signs)
What is the order of the oestrus cycle in cows?
Oestrus
Metoestrus
Dioestrus
Proestrus
Name 4 signs of oestrus in cattle
Standing to be mounted Flehmen response Vulval swelling Mucoid vaginal discharge Holding milk Restless Mounting other cows Vulva sniffing
What must happen after calving to succesfully establish a pregnancy?
Uterus involution
Restoration of endometrium (cotyledons no longer present 25d post-partum)
Resumption of ovarian cyclicity
Insemination, fertilisation and maintenance of pregnancy
Cystic ovarian disease can be follicular or luteal and symptoms can range from anoestrus to nymphomania. When does COD typically occur?
Lactation - <60 DIM
Give examples of what may be associated with cystic ovarian disease
High production NEB, ketosis Raised NEFAs Twinning/peri-parturient problems Genetic predisposition XS BCS at drying off Higher parity
Follicular cysts are fluid filled and thin walled. What diameter are they? How long is there duration?
> 2.5 cm
Duration >10 days
Follicular cysts arise from follicles that fail to ovulate. Give examples of what may cause a follicular cyst
Anything interfering with GnRH/LH
Negative energy balance
Mastitis or other illness
Lameness
As follicular cysts grow in size, what hormone do they produce in the first half of their life if they are previously exposed to progesterone from a CL?
Oestradiol
When are follicular cysts hormonally inactive?
If a CL > 2cm size is present on either ovary
Focus treatment on CL
How can persistent oestrus seen with follicular cysts lead to a not-seen bulling cow?
Persistent oestrus causes nymphomania
Leads to frustration and giving up
If you are unsure if a cyst is luteal or follicular, what should you do?
PRID
Luteal cysts are luteinised follicular cysts with thick walls and fluid filled lacunae. Luteal cysts produce which hormone?
Progesterone
prevent/maintain pregnancy
How can a mummified foetus be treated?
Prostaglandin or cull
Difficult to remove and poor prognosis
When are foetal membranes classed as retained in cattle?
12-24 hours post-parturition
What is RFM in cows linked to?
Obesity
Milk fever
What are the sequelae of RFM?
Decreases milk yield
Causes uterine infections - may affect fertility
What is subclinical endometritis?
WBCs in uterus when flushed with saline or cytobrush
How is endometritis treated in cattle?
Prostaglandin
If fails, metricure
How is metritis treated in cattle?
Systemic anitbodies
NSAIDs
+/- fluids and calcium
What are the 3 main groups of oestrus synchronisation?
Prostaglandin based
Progesterone based
GnRH based
Which method of synchronise does not work effectively in heifers?
GnRH based (Ovsynch) (Fixed time AI)
How is prostaglandin given to manipulate oestrus?
2 injections 11 days apart
Come into oestrus 3-8 days later
What is the Ovsynch/GnRH oestrus synchronisation protocol?
Day 0 - GnRH
Day 7 - prostaglandin
Day 9 - GnRH
Day 10/11 - AI
Which synchronisation method has poor results with fixed time AI?
PRID/progesterone based
How is progesterone given to manipulate oestrus?
Insert PRID
Remove after 7 days and administer prostaglandin
Will come into oestrus 1-5 days later
What can be used to abort a pregnancy in the first 100 days?
Prostaglandin
Works up to 150
When should post-partum vaginal/rectal checks be performed?
3-4 weeks post-calving
What is lochial discharge?
Normal discharge after calving
May be confused for endometritis - hence waiting 3-4 weeks for post-partum check
How many days after pregnancy do dairy cows start cycling again? When is a cow classed as not-cycling?
25-30 days
If 45+ days, prolonged anoestrus
You are doing a routine PD visit and a cow has one large dominant follicle and no CL. What stage of the oestrus cycle is she in?
Oestrus
Ready to serve (can give GnRH to prevent coming cystic)
When can prostaglandin be used to induce abortion?
Day 6-150
steroids after this
Where is progesterone made? Where is prostaglandin made?
Progesterone - CL
Prostaglandin - endometrium
What is the voluntary waiting period in cattle?
50 days
What happens if you give a cow with a CL prostaglandin?
Ovulate 2-5 days later
A cow has a CL >2cm, what stage is she in?
Dioestrus
If a cow has a CL <2cm, what stages could she be in and how would you tell them apart?
Proestrus - large follicles
Metoestrus - if blood on vaginal exam
If the CL is less than 2cm, what can you do?
Give GnRH if problem cow
Otherwise wait until oestrus
How long do pregnant cows have a CL for?
Entire pregnancy
A cow has a CL >2cm and you decide she is in dioestrus. What can you give her to cause ovulation and when does this occur?
Give prostaglandin
Ovulate 2-5 days later
What drug can be given to induce parturition of sows with a known service date?
Deep IM Prostaglandin
When can progesterone sponges be used in sheep to synchronise oestrus?
If already cycling
E.g. if running with teaser ram
