Pregnancy Detection Flashcards
In general how is pregnancy detected?
- Palpation of the reproductive tract (trans-rectal or abdominal)
- Imaging of the reproductive tract (radiograph or ultrasound)
- Measurement of hormone concentrations (blood or other fluids)
How is pregnancy detected in beef cattle herds?
- Have a controlled breeding season - 60-90 days
- Done through a herd assessment:
- Goal - get a lot of cows pregnant (most in the first 20 days of breeding)
- Determine success of proceeding breeding season
- Provide diagnostic information
- Identify open cows for alternate management
How is pregnancy detected in Dairy Cattle herds?
- Some dairies are seasonal - controlled 60 day breeding season similar to beef herds
- Most dairies breed year-around
- Results in steady milk supply
- Mostly an individual cow assessment
- Determine dry-off date (40-60 day prior to lactation)
- Determine if cow should continue in breeding pool
- Assess herd breeding program
What types of pregnancy tests exist for cattle?
- Milk or blood progesterone assay
- Milk progesterone values correlate with blood values
- Remember the fluctuation of progesterone concentrations over an estrous cycle
- Must know breeding date - and test at specific time after that breeding date (21-24 days post breeding)
- If progesterone is found to be low = Not pregnant
- If progesterone is found to be high = pregnant or in diestrus
- PSPB - Pregnancy specific protein B
- Can be detected as early as 25 days of gestation
- Remains in blood for up to 3 months after parturition (or abortion)
- Early Conception Factor (ECF)
- Can be detected as early as 6 days of gestation
- Although promoted by advertisements and anecdotal testimonials
- Results of studies have shown unacceptable accuracy (48-96% false-positive, 14-95% false negative)
- Detection of Estrus
- Ultrasonography
- Routinely accurate at 28day gestation
- Can determine sex of fetus between 55-65 day gestation (up to 75day - but more difficult)
- very difficult as fetus grows and uterus pulled over pelvis (~ day 90)
- Uterine palpation per rectum
- Routinely accurate by 35 day gestation (possible by 28 days)
- Fast and accurate with experience
- Less information than ultrasound
- ovarian structures, fetal sex, fetal viability
How can the age of gestation in cattle be determined?
- Fluid Volume:
- 35 days = slight amount of fluid in the uterus
- able to “slip” fetal membranes
- 40 days = 75mL
- slightly more fluid than 35 days
- Uterine wall is thinning
- 60 days = 300mL
- Pregnant horn is size of a banana
- Still able to hold the entire tract in hand
- 90 days = 1000mL
- Can still reach around entire tract - but just barely
- Routinely “bump” the calf
- Routinely feel placentomes
- 120 days = 3000mL
- Cannot reach around entire tract
- Placentomes are prominent - neckel-sized
- Fremitus in mid-uterine artery on pregnant side
- 35 days = slight amount of fluid in the uterus
What structures can cause confusion when trying to determine the age of gestion in cattle?
- Bladder
- Back of Rumen
- Left Kidney
- Gas bubble in intestine
- Pyometra
- Lymphoma
- Uterine involution (post calving)
What are the different ways Ultrasound can be utilized in pregnancy detection and gestation determination in cattle?
- Pregnancy Diagnosis
- a little earlier preg detection
- 28 days vs 35 days
- Able to assess fetal viability
- Able to determine sex
- Little slower than palpation
- “Wow” factor
- a little earlier preg detection
- Sex determination:
- Genital tubercle is in noticeably different position by about 55 days of gestation
- located immediately caudal to umbilicus in male
- located just ventral to tail in female
- Much past 70 days - difficult to consistently get right area of fetus on the screen
- Genital tubercle is in noticeably different position by about 55 days of gestation
- Recognize early embryonic loss
- ~17% of 28-day embryos are lost by day 56
- Early pregnancy detection (US or palpation ) does not Cause embryo loss (unless very rough)
- Embryo Transfer
- Identify recipients with CL
- Follow follicular dynamic of donor cow - count CLs at flushing
- Dairy - Early non-pregnancy determination coupled with re-synchronization protocol
- coupled with timed insemination to optimize use of labor
- reduces “days open”
How does an Integrated Reproductive Program in cattle work?
- All reproductive activities are on Tues and Thurs
- Ultrasound every Tuesday
- AI every Thursday
- 35 day interval between AI breeding
How is Pregnancy detected in Horses?
- Equine Chorionic Gonadotropin (eCG)
- At 36-38 days of gestation, fetal chorionic tissue invades the endometrium and forms endometrial cups - these cups secrete eCG (aka PMSG)
- eCG acts to luteinize the normal follicular waves tat are occurring and results in the formation of secondary (accessory) CLs
- eCG levels peak about day 60-80 of gestation
- eCG assays will detect a high percentge (>90%) of pregnancies by day 42 (may be a good alternative for miniature horses)
- But, eCG remains elevated if the pregnancy is lost - therefore a non-pregnant mare can have high serum eCG values
- Estrogens
- Cuboni Test
- Fluorescence of urine due to estrogen
- Will accurately detect pregnancy by 100 - 150 days of gestation (also easily palpated per rectum)
- Estrone sulfate:
- Present in serum, urine and even feces of the pregnant mare
- Because non-invasive samples can be used - this test is utilized for assessing wild equine reproduction
- After day 44 of gestation, high estrone sulfate is associated with fetal viability
- Early Pregnancy Factor (EPF)
- Immunosuppressive protein secreted by the early embryo
- Detected as early as 24-72 hours after mating and remains elevated through the second trimester of gestation (no present in 3rd trimester)
- Poor test accuracy (sens 43% / spec 52%)
- Cervical Tone and appearance
- Progesterone from CLs (primary and accessory) peak at day 80-90
- High levels of progesterone cause the cervix and uterus to have exaggerated tone
- From day 16 to the end of gestation the cervix is elongated and firm and the uterus has an increased tone
- Uterine palpation per rectum and transrectal ultrasound
- Chorionic vesicle is distinctly spherical (early gestation)
- Vesicle is palpable from d 18 to 60-70
- Vesicle is visible via ultrasound beginning ~day 10
Can ultrasound be used for fetal sexing in mares?
- Genital tubercle migrates toward the umbilicus in the male and the anus in the female
- Fetal sex is determine from day 59-68
How can Pregnancy be detected in canines?
- Abdominal palpation
- start at the dorsal abdomen and move your hand downward and squeeze thumb and fingers together gently - slip the uterus between the thumb and fingers
- Day 21-31 (after the start of diestrus) the pregnancy can be palpated as small, firm, round vesicles (about the size of walnuts - 1.5-3.5cm)
- Accurate counting of fetuses is not possible
- Determining fetal viability is not possible
- Palpation may be difficult in large dogs, dogs with tense abdomens, dogs with a lot of mammary development
- From day 31-50 the vesicles lose their distinct round shape and are not detectable by palpation
- After day 50 the puppies are palpable
- Trans-abdominal ultrasound
- Fetal vesicles are visible by day 18-20 pat the LH peak as distinct, round black (fluid-filled) sacks
- Fetal heartbeat (first seen day 23-25 after LH peak) & fetal movement (first seen 34-36days after LH peak) are indications of fetal viability
- HR >20bpm is an indication of fetal stress (late in gestation)
- Ultrasound s more accurate than palpation
- Difficult to count fetuses (can differentiate between large and small litter
- Radiograph
- fetal skeletons first seen 42 - 52 days after breeding 44-47 days after LH peak (20-21 days prior to parturition)
- after day 50 fetal skeletons can be counted
- Relaxin - measure from blood sample
- Detected by day 20-30 past LH peak
- Commercial kit is available
How is pregnancy detected in pigs?
- Detection of return to estrus
- Non-pregnant sows should return to estrus 17-24 days after breeding
- Sow’s behavior should be evaluated in the presence of a boar
- False positive results are common (flalsely ID female as bred)
- A-Mode ultrasound
- Use US waves to detect fluid-filled uterus
- Output: audible signal or a series of lights
- High accuracy 30-75 days
- Number of false-negative results increases after day 75
- Doppler ultrasonography
- Detects movement such as fetal heart and pulsing umbilical/uterine arteries
- Output is an audible signal
- High accuracy after 30-34 days
- Risk of false-positive during proestrus or estrus
- Real-time ultrasonography
- Expensive - so not used on small farms
- Able to detect pregnancy sooner than with A-mode or Doppler US (d 23 vs d 30)
How is pregnancy detected in ovines?
- Real-time US
- Can detect pregnancy and assess fetal numbers as early as day 25 gestation
- Pregnancy-specific protein B
- Can be detected as early as day 20 of gestation