TV4001: Bovine Repro Flashcards
Which hormone induces regression of the Mullerian ducts? Why is this relevant to freemartinism?
AMH.
AMH from male foetus causes regression of mullerian ducts in female foetus. This leads to hypoplasia of the female reproductive tract and subsequent sterility.
Which hormone causes masculinisation of the freemartin’s reproductive tract?
Testosterone
What is the most important diagnostic sign of a freemartin?
Short, blind-ending vagina
What are the three possible cyst outcomes in cystic ovarian disease?
- Cyst persists for extended period
- Regress and replaced by another cyst
- Regress and replaced by follicular structure that ovulates
Describe the two types of cysts in cystic ovarian disease
Thin-walled: follicular
- systemic P4 is low
- may secrete oestradiol
Thick-walled: luteal
- systemic P4 usually high
- lutenisation of thecal and granulosa cells = secrete progesterone
List some of the clinical signs of cystic ovarian disease in cattle
**anoestrus
- persistent oestrus
- erratic oestrus behaviour, more freq than expected
- “sterility hump”
- infertility
- follicles >2.5 cm on rectal exam
What is the only definitive sign of oestrus? List some secondary signs
Definitive: standing to be mounted
Secondary:
- Mounting
- Disoriented mounting
- Flehmen response
- Aggressive behaviour
- Clear thin vaginal mucous
- Swollen vulva
- Increased walking
- Raising head above herd
- Decreased milk
- Rub marks at pin bones and/or base of tail
List some of the factors that may affect a cow showing behavioural signs of oestrus
- how many cows are together
- age
- env e.g slippery floors
- lameness
- health
- nutrition
- stress
- climate extremes
- breed (Bos indicus less likely to show signs)
- synch method e.g GnRH
- moving animals
What is the sensitivity (efficiency) in the evaluation of heat detection? How do you calculate it?
Percentage of oestrus periods detected that occurred in a given time.
= (no cows detected in oestrus / no cows in oestrus) x 100
What is the Positive Predictive Value (PPV) in evaluation of heat detection? How do you calculate it?
The probability that the test is correct
= (no correct detections / no correct and false-pos detections) x 100L
List some of the ways you could improve efficiency and PPV in the evaluation of heat detection
- Improve cow ID and record keeping
- Spend time observing cow behaviour
- Place suspicious cows with oestrus cows
- Heat detection aids
- Optimise health and nutrition
- Train staff
- Sync oestrus
List some aids in detecting oestrus
- Tail paint
- Marking crayons
- Kamars/Bulling beacons
- Etrus alert
- Pedometers
- Progesterone levels
- Hormone detector animals
What precautions should you observe when using PGF2a or its synthetic analogues to sync oestrus in cattle?
- Be aware of health and safety for administrator: resp difficulty, abortion
- Can cause abortion in preg cattle
At what stage of the cycle is an injection of PGF2a most likely to cause luteolysis in cows and in heifers?
Cows: day 7-18
Heifers: day 5-18
What percentage of cows in a randomly cycling group of cows would you expect to enter oestrus after a single injection of PGF2a?
About 75% (?)
