Pregnancy Diagnosis in farm animals Flashcards
why do pregnancy diagnosis (PD)
usually to detect non-pregnancy stage of pregnancy accurate time for drying off cattle, date of birth number of foetuses accurate feeding
methods for PD
non-return to oestrus in polyoestrus species
measurement of hormones + other substances that occur in pregnant animals
detection of gravid uterus + contents - palpation, ultrasonography, radiography
indentify changes in gross + microscopoic structure of genital system
early pregnancy in cow
after proper service
90% have fertilised oocyte
from 13 days interferon tau is made by embryo
prevents luteolysis of CL
embryo loss
90% pregnant before 21 days loss 22% 21-42 days loss 6% 42+ days 5% early PD - apparent higher loss rate
PD - cow
non-return to oestrus after service, 18-24 days
ultrasonography from 30 days
progesterone in plasma + milk, 21-24 days
membrane slip - palpate chorioallantois
disparity in horn size from 25 days
palpation of foetus 45-60 days
oestone sulphate in milk + plasma from 105 days, best at 120
palpate foetus day 120
progesterone analysis
milk or plasma
milk has higher conc’s, so better discriminator between empty + pregnant
ELISA - on farm/lab
day 24 accuracy - low P4- PD neg 99%, high P4 - PD +ve, it’s a test for non-pregnancy
false +ve PD milk progesterone
luteinised cyst persistence of CL error in ID/labelling shorter than normal oestrous cycle incorrect timing of AI inadequate mixing of sample embryo mortality
ultrasound
transrectal 7.5 MHz + late 5 MHz head favourable lighting moderately expensive equipment care with machine biosecurity
disparity in horn size
beware of false +ve incomplete involution fluid in horns pus (pyometria) mucous (mucimetria) watery secretion (hydrometria)
oestrone sulphate
oestrone produced by feto-placental unit
conjugated to sulphate in fetal liver
blood sample
use from 120 days
PD - ewe
*non-return to oestrus 16-19 days after service
plasma progesterone assay 15-18 days after service
transabdominal B mode ultrasonography as early as 30 days
doppler ultrasound transabdominally from 50 days
vaginal biopsy
palpation of caudal uterine artery from 60 days
radiography
PD - goat
fail to return to oestrus around 21 days after service
milk or plasma P4 21 days
*oestrone sulphatein plasma or milk from 50 days
*transabdominal B mode ultrasonography from 30 days
abdominal palpation
PD - sow
*non-return to oestrus 18-22 days after service
plasma progesterone assay
oestrone sulphatein plasma or milk from 24-28 days
transabdominal B mode ultrasonography from 12 days
vaginal biopsy
