Ruminant Anesthesia

T/F: Regurgitation is an important problem during ruminant anesthesia that can be prevented

False, it is an important problem but it can’t be prevented

Ruminants produce a lot of _______ which can be an additional unique factor for them during anesthesia

Saliva

Because Ruminants are prey species it can be much more difficult to assess their ____

Pain, they are much better at hiding it

What is the universal pain scale used for ruminants?

UNESP-Botchu pain scale (it has variations for each species. Cattle, sheep, goats)

What are the 5 goals of anesthesia?

1. Patient should be unconscious

2. Patient should be immobile

3. Provide Analgesia

4. Avoid complications

5. Safe induction and recovery

T/F: Like horses, ruminants should not be fasted before a procedure

False, fasting is very important for ruminants since regurgitation and chewing their cud is common and happens often

All ruminants should be fasted expect for _______

Neonates (their rumen isn’t fully developed yet and they are at risk of being hypoglycemic if you do)

How long before surgery should ruminants be fasted for?

• Adult Cattle (18-24 hrs)

• Adult sheep/goats (12-18 hrs)

What advantages are there to fasting ruminants before anestheisa?

1. Preserve a better FRC (Functional Residual Capacity) - which does reassess the risk of hypoxemia

2. Reduces the likelihood of bloat during anesthesia/recumbency

What is the FRC (Functional Residual Capacity)?

• Air left in the lungs after normal passive exhalation

• If the FRC decreases then the patient is more likely to develop hypoxemia

Prolonged fasting beyond the recommended time is not good for ruminants, what are some negative side effects of prolonged fasting (>24hrs)?

• Hypomotility of the Rumen

• Bradycardia (decreases rumenoreticular fill → increases parasympathetic tone → bradycardia)

• Regurgitation more likely

• Dehydration

Which act allows for ELDU (Extra Label Drug Use) in vet med?

AMDUCA of 1994

What are the requirements for ELDU?

When the animals health is threatened or death may result without intervention

When prescribing meds extra label, what resource can you use to estimate withdrawal times and get updates on prohibited ELDU?

FARAD (Food Animal Residue Avoidance Databank)

If you have a healthy and normal ruminant for a standard procedure, what type of pre-op BW is required?

PCV + TP

Weight is a very important objective piece of information that is necessary to gather before a procedure, what are the 2 methods of collecting a ruminants weight?

1. Scale

2. Estimation via girth circumference

What are the 5 non-species specific risks/complications of anesthesia?

1. Hypotension

2. Hypoxemia

3. Hypoventilation

4. Hypothermia

5. Bradycardia

4H1B

What are some ruminant specific anesthetic complications?

1. Regurgitation and excessive salivation

2. Aspiration pneumonia

3. Ruminal tympani (bloat)

Why are ruminants more prone to aspiration?

They are constantly regurgitating (active and passive)

How can you reduce the risk of fatal aspiration in ruminants?

• Appropriate fasting and water deprivation

• Protect the airway

• Point head downwards (so regurgitations are less likely to be aspirated on)

Does giving Atropine (anticholinergic) help prevent excess salivation in ruminants?

No, it only reduces the aqueous portion of the saliva, which actually has the opposite effect making the saliva thicker and harder to clear

T/F: Like horses, you have to worry about neuropathy and myopathy in ruminants due to positioning

True

Why is bloat such a concern in ruminants during anesthesia?

• Fermentation of their ingests continues while they are under anesthesia, so gas production doesn’t stop

• Gas accumulation has negative side effects

  1. Decreases the FRC and impedes ventilation

  2. Increases the risk of regurgitation

T/F: Most routine surgical procedures in ruminants is performed via general anesthesia

False, it is typically done via sedation and line blocks

When sedating ruminants be careful administering ______ as they are sensitive to it

Xylazine

Which is more sensitive to Xylazine?

1. Goats or Cattle

2. Brahmans or Holsteins

1. Goats

2. Brahmans

What are some of the negative effects that can occur with Xylazine administration in ruminants?

1. Ruminal Hypomotility

2. Uterine contractions

   1. It has oxytocin like effects

If you are trying to avoid causing rumen hypomotility, ____________ is a good alternative for sedation

Benzodiazepines (Diazepam/Midazolam)

If you are performing an abdominal surgery in a ruminant, what are the 3 options for local blocks?

1. Paravertebral block

2. Inverted L block

3. Line Block

______________ (Analgesia) is prohibited from being used in dairy cattle >20 months of age

No Phenylbutazone

Which sedative when given to a ruminant in late gestation, has oxytocin-like effects and cause uterine contractions?

Xylazine (Alpha-2-Agonist)

Alpha-2 agonists can cause dose-dependent hypoxemia and Pulmonary edema in what species?

Sheep

What is the most common combination of induction drugs that are used in ruminants?

Ketamine + Benzodiazepine

T/F: While you can use Propofol + Alfaxalone as a induction agents for adult cattle, it is not practical due to price

True

Before intubating cattle for ET intubation why is it important to ensure that the patient is in the proper anesthetic depth

If the depth is not adequate then the gag reflex is still present → Increased risk of regurgitation

As soon that the ET tube has been placed what is the next step that should occur?

It should be inflated to prevent aspiration

What is the most common method used to intubate a ruminant?

Digital Palpation