Food Animal Drugs
Food Animal Sedatives
In many cases, sedatives are not required in adult cattle. Pain is controlled through local blocks and systemic drugs.
Acepromazine
Acepromazine is an effective calming agent in ruminants. Give prior to additional stimulation and give it at least 20 minutes to work. It does cause penile protrusion but not dangerous levels of priapism.
Xylazine
If needed, xylazine works well in ruminants. However, they are very sensitive to the drug and take only 1/10 of the horse dose. It is almost impossible to make a horse lie down just with xylazine. It is easy to do that in cattle. As with horses, butorphanol can potentiate the effects of xylazine in ruminants, prolonging its duration.
There are times when xylazine is a bad idea:
- Pregnant cows – xylazine causes uterine contractions. If a cow is in her third trimester and is given xylazine, she might abort. It also makes Csections harder. This would be a better time for ace/butorphanol.
- Neonatal animals – cardiac output is heart rate x stroke volume. If you use xylazine, you slow heart rate. However, neonatal animals can’t adjust stroke volume. So you end up with minimal cardiac output. Not good. You can use butorphanol alone in this age group – they get sedated vs excited. We also use the benzodiazepines – diazepam and midazolam for calming.
- Hot days –xylazine interferes with thermoregulation and animals can become dangerously overheated.
- Blocked goats – xylazine increases sugars in the urine which leads to diuresis and more urine volume. This isn’t good if the goat is blocked and can’t pee. Only use xylazine if you are ready to empty the bladder.
- Pigs – xylazine doesn’t work well (they are very insensitive) and they tend to vomit. Used but not a great drug. Benzodiazepines and butorphanol combos are better.
- Sheep – sheep can develop fatal pulmonary edema. This is a relatively new finding but obviously scary. The risk is highest with general anesthesia and with higher doses given iv. We aren’t sure yet if the problem occurs in goats. So be aware of the risk and try to use other drugs such as the benzodiazepines.
If you do have to use xylazine, avoid rapid iv injection and have reversal agents on hand.
Detomidine
Ruminants are NOT more sensitive to detomidine. Detomidine is used in small ruminants because the dosing is easier. However, it is an expensive drug so is rarely used in cattle. Detomidine does cause increased pulmonary resistance (and probably edema) in sheep.
Romifidine
- Adult cattle – 3-20 ug/kg iv or 20-40 ug/kg im
- Calves – 3-50 ug/kg iv or 50-100 ug/kg im
- Sheep/goats – 3-40 ug/kg iv or 40-80 ug/kg im
Butorphanol
Butorphanol sometimes causes sedation and sometimes causes excitement in ruminants. It is best to use it with a sedative or tranquilizer to minimize the risk of excitement. However, unlike in horses where we make sure they are sedated first, we can combine the drugs in the same syringe for cattle and give at the same time. We use ace-butorphanol combos for standing surgery in cattle as well as xylazine- butorphanol combos. Morphine can be substituted for butorphanol.
Ketamine
Ketamine (dissociative anesthetic agent) can be used in combination with xylazine and butorphanol to create a standing sedated state in ruminants. It is not used this way in horses. See the general anesthesia chapter for more information about ketamine.
Reversal agents
If the animal is too sleepy, the alpha-2s can be partially reversed using drugs such as atipamezole and tolazoline. Narcotics can be reversed with naloxone. Butorphanol is actually a partial agonist-antagonist narcotic so it can reverse other narcotics.
Withholding – meat and milk
None of these agents are approved in food animal species. FARAD should be consulted for appropriate milk and meat withholding times
An anesthetic that distorts sensory perceptions and causes feelings of detachment from reality.
The amount of time needed for the drug to leave the tissues so that they are safe for human consumption. The standard tissues are meat and milk. FARAD.org is the main source of information for how much time is needed.
