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Sample Collection in Cattle

Venipuncture

• Common sampling site in cattle: Jugular vein.

• Supplies needed before starting:

  • Proper restraint equipment

  • Squeeze chute for security.

  • Halter to pull the cow's head to the side.

• Wipe the Area:

  • Clean the area with alcohol or another wetting solution.

  • The speaker expresses a dislike for alcohol:

  • Reasons:

    • It burns and has a noxious smell.

    • Alcohol does not effectively clean the area unless the area is shaved and allowed to dry.

    • It does not aid in raising the vein.

  • Best practice: Use a wetting solution to facilitate palpation, but it doesn’t have to be alcohol.

  • Distending the vein is key for palpation.

Preparing to Collect Blood Sample

• Use a 16 to 18 gauge, 1.5-inch needle with a syringe or a vacutainer system.

  • Personal preference expressed for the vacutainer system.

• Technique:

  • Hold off the vein in the jugular furrow firmly.

  • Palpate the vein before insertion.

  • Insert the needle almost perpendicular to the skin (exceptions: young animals may require a 30-degree angle).

  • Pull back on the plunger to collect blood.

  • It is critical to release distension before removing the needle to prevent hematomas and bleeding.

• Using a vacuum tube:

  • Engage the tubes post-insertion to collect blood directly into the tubes.

IV Injections

• Essential to ensure the head of the cow is restrained properly during injection.

• Proper preparation involves:

  • Head restraint: Tightly tied halter and nose lead for less tension.

  • Clean the area over the vein lightly.

  • Maximize vein size by stroking or holding off distally, allowing blood to fill the vein.

• Insert needle into the vein directly and quickly, transferring blood into appropriate collection vessels promptly to avoid clotting.

• Ensure appropriate needle length and gauge for injections:

  • Recommended: 14 gauge, 2-inch needle.

  • A perpendicular angle of entry helps retain needle position while administering medication.

• Administration checks:

  • Ensure blood flow to confirm needle position.

  • Always rub the vein after withdrawal to prevent leakage or hematomas.

  • Gloves are recommended for hygiene.

Alternative Venipuncture Site: Tail Vein

• Safer than the jugular as it avoids risks associated with head restraint.

• Procedure:

  • Clean the underside of the tail thoroughly; it can be a dirty area.

  • Use an 18 to 20 gauge, 1.5-inch needle.

  • Needle insertion between the vertebrae at a perpendicular angle.

  • Withdraw blood once flashback is noted.

  • Apply pressure to the site post collection before returning the tail to its natural position.

Collecting Rumen Fluid

• Techniques for collecting rumen fluid:

  • Orogastric Technique using a Frick speculum to prevent chewing of the stomach tube:

  • Insert the Frick speculum first, then thread the rumen tube through it.

  • Ensure it's positioned correctly to collect the fluid.

  • Suck on the tube to retrieve rumen fluid into a container (immediate processing required).

  • Ruminocentesis for direct collection:

  • Prepare the site caudal to the last rib with a 14 gauge, 1.5 to 3-inch needle.

  • Potential for food particles blocking the needle, making this method less common than orogastric.

Administering Oral Fluids

• The procedure is similar to rumen fluid collection, utilizing a Frick tube for direct administration.

• Equipment:

  • Attach to a pump for administering fluid directly into the rumen.

• Ensure to remove the Frick tube without losing contents or harming the cow.

Abdominocentesis (Peritoneal Fluid Collection)

• Essential equipment includes:

  • 18 to 20 gauge, 1.5 to 3-inch needle.

  • Perform slightly to the right of midline; be cautious of the milk vein in dairy cows to avoid hematomas.

• Avoiding Milk Veins: Important to prevent compromising blood flow from the mammary gland.

Collecting Urine Samples

• Generally more difficult compared to other species due to anatomy:

  • Male cats are particularly challenging due to the sigmoid flexure, which complicates catheterization.

• Manual stimulation in females:

  • Stimulate the area below the vulva for urination.

  • Immediate readiness for sample collection is essential.

• Catheterization: Typically not performed in males unless absolutely necessary.

Collection Methods for Feces & Milk

• Fecal Collection:

  • Don a glove, collect directly from rectum using a hand-scooping method.

• Milk Collection:

  • Clean and dry the teat first.

  • Perform stripping to discard the initial milk before sampling.

  • Suggested collecting method: use small bags or sterile containers.

  • Composite samples involve collecting from all four quarters, while quarter samples focus on specific quarters affected by mastitis.

Final Notes

• Ensure all procedures respect animal health and safety standards.

• Be prepared for immediate processing of biological samples to ensure accuracy of results.

• Always consult for clarification on procedures you find challenging or need further guidance on.