Pregnancy Diagnosis in Large Animals Flashcards
What do we need to know to enable proper management of pregnant animals?
Stage of pregnancy
Number of foetuses
Methods of pregnancy diagnosis?
Non-return to oestrus in polyoestrus species Measurements of hormones Detection of gravid uterus: - Manual palpation - US - Radiography
What prevents luteolysis in the cow from day 13?
Interferon Tau produced by the embryo
When is there most pregnancy loss?
Before 21 days = 22% loss
21-42 days = 6% loss
42+ days = 5%
Early PD means there are apparent higher losses
Methods of PD in the cows from early to late…
Non return to oestrus (18-24d) Progesterone in milk 21-24d US from 30d Membrane slip 33d Disparity in horn size 35d Palpation of foetus 45-60d Presence of placentomes 80d Uterine artery 85d Oestrone sulphate in milk 105d Palpation of foetus 120d
Describe how non-return to oestrus can be inaccurate as a PD…
100 cows inseminated
50% preg rate
Of those not pregnant farmer only detects 60% heat
Number of pregnant animals greatly overestimated
Describe milk progesterone assay…
Measure milk progesterone at day 21 Milk has higher concentrations than plasma so better ELISA on farm If low progesterone =99% not pregnant If high = could be +ve or -ve
What would cause a false +ve PD on milk progesterone assay?
Luteinised cyst Persistent CL Error in ID Shorter than normal oestrus cycle Incorrect timing of AI Inadequate mixing of sample Embryo mortality
What does the US of a day29-32 foetus look like?
Foetus starts to migrate into lumen so can start to see it
What does US at day 42 look like?
Can start to see amniotic sac around foetus
What is membrane slip?
Can palpate chorioallantois as it is loosely attached to uterine wall
How can disparity in horn size in PD give a false +ve?
Incomplete involution Fluid in horns Pus (pyo) Mucous (mucometra) Watery secretion (hydro)
