Animal handling lecture 4- ultrasounding

How does an ultrasound machine work? (3)

• Ultrasound machines have a transducer (probe) that emits and receives high-frequency sound waves

• The sound waves emitted encounter tissue that causes the waves to bounce back to transducer as echoes

• The echoes are captured by the computer/machine to create an image

Ultrasound machines

• Come in many sizes

• prices range from - $600-$33,000

• probe prices range from- $300-$10,000

How do the different tissues appear?

the more dense a tissue is, the more the echoes bounce back

When observing bones through an ultrasound

Bones = white because they have lots of echoes bouncing back (HYPERECHOIC)

When observing muscle on an ultrasound

Muscle = grey because some/less echoes bounce back (Hypoechoic)

When observing fluid through an ultrasound

Fluid = Black because there are no echoes bouncing back (anechoic)

4 benefits of ultrasounds for pregnancy detection

1. Allows for early detection of pregnancy

   1. Sheep and goats- as early as 40 days post mating via TRANSABDOMINAL method

      1. Pigs- as early as 24 days post mating via transabdominal method

         1. Cattle- as early as 30 days post mating via rectal ultrasound method

   2. In ewes/does- able to see if she is carrying multiple fetuses

   3. Ultrasound can be a non-invasive technique, via transabdominal method (in sheep, goats, and pigs)

   4. High accuracy

2. (Based on pregnancy status, allows for management decisions including nutrition, culling, and breeding strategies)

How to detect pregnancy in sheep/goats using ultrasonography- Transabdominal method

• have the sheep held by someone, tied up, or in a chute

• add gel to the probe and inner flank (gel eliminated air and forms a bond between the skin— if image is dark, you add gel)

• place the probe in a non-wooly area and put some pressure on

• Aim towards the MIDLINE of the animal

What to look for > 40 days pregnant

• Look for a placentome

• Placentome- Where the placenta attaches the mom’s side to the fetal side. this is important for nutrient and gas exchange between the mother and fetus

• the caruncle is the mom’s side

• the cotyledon is the fetal side and together they make the placentome

• if you see a donut shaped tissue, the animal is pregnant

Identifying a fetus

• In early gestation can be more difficult than determining pregnancy (seeing a placentome)

Ultrasonography in cattle

• Ultrasound transducer/probe used transrectally for early gestation

• ultrasound 30 days after the end of the breeding season can be used to accurately determine pregnancy status (95%-100%)

• Looking for a sac of fluid with a tiny fetus inside

  • can sometimes find placentomes as well but it depends how early in gestation you are

Determining pregnancy in mid to late gestation in cattle

If its later in gestation pregnancy can be detected via rectal palpation

• Insert your arm into the rectum and feel below for the repro tract and for a balloon that can bounce, if you find it, she is pregnant (90 days+)

• If much later in gestation like 5 + months, you can feel the fetus and the fetus will be hanging over the pelvis

  • you can also pull on repro tract with the fetus inside and bring it closer to you, to feel the fetus (head, nose, hooves)

Pregnancy detection in swine- using ultrasound

• Place probe under rear flank area

• EARLY GESTATION- look for irregular black shaped structure which are fluid-filled embryonic vesicles- 24 days after breeding

• MID TO LATE GESTATION- find fetuses- skeleton: easiest to find ribs, spine, head/skull

Gestation in swine

• 3 months, 3 weeks, 3 days