Does baby need to burb after feeding?

Normally I always burb my baby after feed her with milk during the day. During the night, however, when I was very sleepy, and the baby also already slept soundly, does it necessary to burb her?

I tried to do some research about this, and this is what I found:

1. How can I tell if my baby needs to burp?
Your baby may stop feeding, squirm, fidget or fuss during or after feeding if she needs to burp. Contrary to popular belief babies generally do not cry because they need to burp (but they do cry for many other reasons). Swallowed air in a baby's tummy may provide a sensation of fullness, but it does not cause pain.

2. Is it necessary to burp my baby?
This depends on your individual baby. Some babies swallow more air during feeding than others, so they may need burping more often. Bottle fed babies tend to swallow more air than breastfed babies. It is not always necessary to burp a breastfed baby, but his would depend on your individual baby. Bottle fed babies generally need burping. As a guide, try to burp your bottle fed baby mid way and at the end of her feed.

3. How long should I burp my baby for?
There is no set time frame to burp a baby and no set number of burps. Every baby is different. How long you would continue to try to burp your baby would depend on your baby's individual circumstances.
Parents generally spend too much time burping their baby rather than too little time. This may result in your baby being kept awake longer than she should, and in doing so increases the risk of her becoming over-tired. It can then become very difficult to tell if she is then crying because of gas (wind) or tiredness.
Your newborn baby will be ready for sleep very soon after feeding. It's important that you do not spend too long trying to burp her.

4. What if my baby doesn't burp?
It can be very difficult to get a 'sleepy baby' to burp! After feeding, if your baby is content but does not burp within 5 minutes of trying, there's no need to continue. She won't burp every time!
Some babies will cry if you stop during feeding to try to burp them because they want to continue feeding. If your baby is crying but does not burp within 1 or 2 minutes return to feeding.

5. If my baby doesn't burp will this cause any problems?
RARELY! Swallowed air may provide a feeling of fullness, which may mean your baby won't drink as much milk as she would otherwise, but the only downside to this is she will demand her next feed sooner. Sometimes a little or a lot of milk can come up with a burp. This is normal.
Swallowing some air during feeding is unavoidable, so it's important to not 'stress out' over it. In most situations, swallowed air will cause your baby no discomfort whatsoever. The swallowed air will either be absorbed by her body or pass right through.
A baby's distress is commonly blamed on "trapped air, which causes colic". Swallowed air is not a reason for colic. Because distressed babies often swallow additional air as they cry, they frequently bring up a bubble or two after crying for long periods. This can be confusing for parents because it is easily mistaken as the reason for crying, when in reality it was simply a side effect of crying.
A small number of babies may experience discomfort from excessive gas hat is produced in their intestines, which is commonly coupled with frequent watery bowel movements. However, these symptoms which can be related to a number of different reasons such as: an immature digestive system; a digestive disorder; an inappropriate diet; or over-feeding, are not due to swallowed air.

6. Do colic/wind mixture help?
NOT MUCH! The side effects of colic/wind mixtures or medications may potentially create greater problems than the gas (wind) itself. Studies have shown that a small amount of sugar water is just as effective as may colic/wind mixtures in helping a baby to burp.
If you decide to use a colic/wind medication, it's important to avoid mixtures that contain a sedative or alcohol. These can appear to relieve your baby's gas, but in reality they do little more than sedate her. (If you are not sure what's in a colic/wind mixture or medication, ask your doctor or pharmacist.)