Reproductive Case Management

Question 1

Simplify the oestrus cycle of a cow

Answer 1

• Some cows have 2 waves of follicular development per cycle, some has 3 – difficult to guess.
• Oestrogen phase- lose CL, increasing mucus
• Past ovulation – mucus decreases, uterine tone decrease and dark blood staining in the discharge – bleeding off
• Ovaries – increasing dominant follicle up to ovulation (usually ovulate at 14-18mm in diameter), post ovulation cannot find follicle and will start to see development of a CL
• Diagnosis – if she has decent CL, in luteal phase if CL gone and big DF – heading towards ovulation and if no CL, bloody vaginal discharge, just coming out of oestrous

Question 2

What findings do you see around the different parts of a cows oestrous cycle?

Answer 2

Question 3

What do prostaglandins do?

When does the cow come into oestrous after giving this?

Answer 3

Prostaglandin (e.g. Estrumate™)

Causes luteolysis

Progesterone production is turned off.

Cow comes into oestrus – 3-4 days (2-7)

~£4/dose

Some variation between licensed products (e.g. Genestran™ only active isomer)

Some have longer half lives, just want to get rid of CL so doesn’t matter too much. Some use for effect on uterine contraction, so the longer lasting one might make more sense in this one (although the half life is still short anyway)

Question 4

What does GnRH do?

What happens as a results of giving this?

Answer 4

Gonadotrophin Releasing Hormone – GnRH (e.g. Receptal ™)

• Causes large release of LH à will ovulate any follicles there and form new luteal tissue, to produce progesterone, can also trigger FSH release so can stimulate follicular waves if given earlier on
• This results in luteinisation of follicles or ovulation
• New luteal tissue is formed
• Progesterone production increases
• ~£4-8/dose

Question 5

What does progesterone releasing intravaginal device do?

When will the cow come into oestrous?

Answer 5

_Progesterone-releasing intravaginal device
(PRID ™/CIDR ™)_

• Slow release of progesterone over 7-11 days
• Effectively acts as a temporary removable corpus luteum
• If no other luteal tissue is present, removal results in the cow coming into oestrus 2-4 days later
• ~£11/device
• Sudden decrease in progesterone – normally results in oestrus 2-4 days after removal

Question 6

How can we synchronise oestrous with CL regression methods?

Answer 6

• CL regression methods (still rely on heat detection)
  
  • Luteolysis using PGF2a
  • Next ovulation depends on stage of follicular wave
    
    • Could be 2-7 days…
  • Can use multiple PGF2a injections 11-14 days apart to ‘tighten’ luteal phase and ‘fix’ ovulation
• Bunch of cycling cows, give PGF2a and then watch for oestrous. Follicular phase – at least half are early in this, come into oestrous – they were about to anyway
• Small number coming out of heat and no functioning CL – wont have effect on these, wont show heat, wont get served
• Could then jab again a few days later and then do a fixed AI time, double insemination 24h apart – spreading window out a bit more
• Lower CR when served after 2nd jab as wont give precise timing of ovulation

Question 7

How can we synchronise oestrous with inducing follicle ovulation?

Answer 7

• Induce follicle ovulation (e.g. ‘Ovsynch’)
  
  • Fix ovulation rather than regressing CL (if present)
    
    • NO HEAT – ovulation forced before oestradiol peak that drives mounting behaviour
• Better conception rate to fixed time AI than double PGF2a but still worse than observed heat.
• Important to monitor outcome and what the CR is to ovysynch heats as seems to vary a lot from herd to herd

Question 8

How commone in ‘blanket synchronisation’ in the UK?

Answer 8

• Use of “blanket” synchronisation in UK is relatively rare
• Used either as “back-up” (e.g. for cows reaching >100DIM without serve)
• or on individual cow basis
• Not that common in UK but more common in USA. Usually used as a backup, regime where if they get to 80-100 days in milk and not pregnant, then use it to ensure she doesn’t get too far

Question 9

How do we usually treat a follicular cyst?

What about a luteal cyst?

Answer 9

Cysts – if follicular, use GnRH and then revisit 1 week later, then might have luteal cyst and use PGF2a to lyse this

Question 10

For oestrous cycle manipulation, what is available in practice?

Answer 10

• Progesterone devices
• Prostaglandin (PGF2a) analogues
• Gonadotrophin-releasing hormone (GnRH) analogues

Question 11

COW 857

Calved 29/01/19. 52 days in milk (VWP is 45 days in this herd)

Not served

On examination: Vaginal exam clean

Genital tract: Uterus involuted, Right ovary CL, Left ovary 1cm follicle

BCS 3.0

What might you do to thsi cow? Discuss management options and the pros and cons of each one

Answer 11

• Could just leave her or give her prostaglandin
• Leaving her:
• Only a week anyway
• May well not have missed a heat
• If they want to serve her from 45d, they are still cutting time from oestrous by using prostaglandin
• PGF2a would bring into oestrous quicker
• There is phenomena of persistent CL as hard to diagnose them – difficult to be sure it’s the same one even with repeat scans, cannot distinguish if it is new or from before – so an argument to tend towards PHF2a
• Day 3-18 CL present, then declines as head towards oestrous. If this cow is on day 18 of CL, then give PGF2a, will have achieved very little!! Just wasted money possibly as coming into heat anyway. If she was on day 5 of CL, will come into heat day 8 or 9 if given PGF2a and she will have saved 14 ish days. So depends where she is along the CL line! Best case is that we save 14 days, worst case save less. Average days saving – 7 days
• Calving internal – its worth at least 2.50, so 7 (average days we will save if giving PGF2a) x 2.50 = well worth £4 PGF2a
• If they don’t want to PGF2a, why did they bother presenting?
• If persistent – will regress with treatment
• Another benefit for PGF2a – likely to PGF2a several others, so might be an advantage as can AI more at the same time!! Also easier to spot if all coming into heat at the same time, lots of other cows to show behaviour with. Reasonable argument for PGF2a her

Question 12

COW 102

• Calved 04/02/19
• 46 days in milk
• Not served
• On examination
• Vaginal exam clean
• Genital tract
• Uterus involuted
• Right ovary 1.5cm follicle
• Left ovary small
• BCS 2.0

What might be a suitable option to do with her? What her options? What are pros and cons to each

Answer 12

• 25mm or more is usually classed as a cyst
• Reasonable to say she is cycling normally, 15mm follicle is past recruitment point and is heading towards ovulation size
• Options:
• Give GnRH
• Leave her alone
• Likely to do nothing In this case
• Things that might point towards GnRH - her BCS is a little low so might be a cow where HPA axis isn’t working optimally so might nudge towards giving her a little bit of help. Will e useful to know what BCS she calved at, if she was the same, might not need help but if she lost a lot of condition – might need a bit of help
• She is likely to still get served within 21 day period after VWP with either option

Question 13

COW 161

• Calved 17/01/19
• 64 days in milk
• Not served or heats observed
• On examination
• Vaginal exam clean
• Genital tract
• Uterus involuted
• Both ovaries small and inactive
• BCS 2.0

What might be a suitable option to do with her? What her options? What are pros and cons to each

Answer 13

• No follicles can be identified if less than 4 or 5 mm in diameter
• diagnosis – true anoestrous, no CL evident, no reasonable follicles, ovaries small
• How can we tell she hasn’t JUST ovulated and CL still developing, still possible – but as both ovaries are small makes it less likely, also no oestrous behaviour or bloody mucus – cannot exclude it, but less likely
• Options:
• PRID – probably best to go for this in this situation
• GnRH also licensed for anoestrous
• if some follicular development but no follicles that are reaching dominant size, GnRH just supports for more follicular development, but if in deep anoestrous, a PRID is probably a better bet

Question 14

COW 507

• Calved 04/01/19
• 77 days in milk
• Received PG 14 days ago
• Not served or seen in heat
• On examination
• Vaginal exam clean
• Genital tract
• Uterus involuted
• Left ovary CL
• BCS 2.5

What might be a suitable option to do with her? What her options? What are pros and cons to each

Answer 14

• She is also cycling – decent CL
• Options:
• Don’t know if we using heat protection aids, but could do this – give another job of PG and use the aids to assist
• Give PGF2a again, they are usually given 14days apart then served at 72h and 96h after
• Start ovysnch regime – serve in 10days time, so lost a week, but better chance of her getting pregnant this time around?
• Which is best to do? There is no right answer

Question 15

Client wishes to discuss the service management of heifers

Currently at grass

Oldest ~12 months old

Thinking of using AI

TB breakdowns in local herds

Hire bull not an option

Sexed semen in heifers

1. What are the options for getting these AI’d?

Answer 15

• Employ AI company to do this – heat detect and inseminate
• Do nothing option – just do heat detection and AI themselves, but another separate herd to heat detect, cannot run with other herd – so lots more work
• Synchronise with fixed time AI regime (usually involved progesterone insert)
• Could go for prostaglandin type approach, OG the on a set day, anything with responsive CL will come in in next 4 or 5 days, so concentrated heat detection. Anything isn’t served, get another PG, then serve anything we don’t see at 72 and 96h after this
• Give farmer info and allow them to make the choice