providing an additional 30 to 50 units can result in an overdose. An overdose of oxytocin can interfere with the farrowing process by two mechanisms. First it can cause the uterus to contract so tightly around the unborn piglets that they cannot be moved, and second, the strength of this
contraction produces a great deal of pain for the sow, who then stops farrowing.
Injecting oxytocin in the rear of the sow rather than in the neck reduces the chance that the sow will be disturbed and attempt to rise (which may slow the farrowing process) while oxytocin in being given. For injections in the neck, use a 18 gauge, 1″ to 1 1/2″ needle. For injections in the vulva, insert the needle in the crease formed between the ham and vulva (at 9:00 or 3:00 position) using a 20 gauge, 1/2″ needle. Prick the injection site with your finger two or three times before injecting the needle so as not to startle the sow and cause her to jump up.
Once oxytocin has been given, you will need to watch the sow closely for labor activity.
1. If NO signs of labor appear in the next 20 to 25 minutes after the oxytocin injection, give the sow another injection of oxytocin at the dose recommended by your veterinarian. If there are no obvious signs of labor, usually it is appropriate to give a second injection of oxytocin without first checking the birth canal. If the sow has not been observed closely for signs of labor since the first injection of oxytocin, the birth canal should be checked to see if it is open before a second injection of oxytocin is given. If no labor is evident in the next 20 to 25 minutes (after the second oxytocin injection), gently get the sow out of the crate for about 10 minutes of mild exercise.
2. If sow DOES show signs of labor soon after the first oxytocin injection, but no piglet is born or the placenta is not evident and 30 minutes has elapsed, enter the sow to see if the birth canal is blocked. Deliver any piglet you can reach. Give the sow a second injection of oxytocin.
If the sow is hot (breathing more than 35 breaths/minute) drip water and turn a fan on her. Call a veterinarian or supervisor if two hours have passed since the last piglet was born and the sow likely has more piglets to farrow. The time intervals given are sufficient for most sows. However, if a sow is at high risk of experiencing a prolonged farrowing (i.e., 5th parity or older, heat stressed, or over conditioned) it may be wise to implement assistance more quickly.
Federal law restricts oxytocin to use by, or on the order of a licensed veterinarian. Pregnant women should be extremely careful handling oxytocin. To maximize safety on the farm, women of childbearing age should avoid handling oxytocin.