Weighing The Pig Will Not Make It Fatter

Weighing The Pig Will Not Make It Fatter

As the title suggests this is very true but we find having the data gives you something to act on which is why we bring all our weaners, growers and finishers out of their paddocks up to our weigh scales and weigh them. It is quite a task to move every animal each and every week but there is method behind our madness.

The first and foremost reason for doing this is to make sure our pigs aren’t overeating and becoming fat little piggies. Not eating enough also means they aren’t going to grow or worse go backwards in weight. Berkshire pigs don’t just become the most delicious tasting pork you have ever tasted by themselves. They need to be fed the correct amount of the right diet at the right time or they put on too much fat.

We use weigh scales for our pigs because our system reads their EID tags at the same time. This means we can match the weight against the pigs identity record easily. If you are starting out with pigs and don’t want to go to the expense of a weigh scale system then the string method will give you a good estimate. We have provided instruction for the string method at the bottom of this post.

We will go into the different feed types and amounts in another post so for now we will explain what different groups we have and why we weigh each group. I will note here that one of the benefits of having pigs in different groups allows smaller pigs to feed without competition from the larger ones.

We will start with the weaners. This group is generally anything from 10kg to 30kg in weight. They are fed an ad-lib diet so once they reach 30kg we definitely don’t want them hogging into food all day long. The pigs that reach 30kg are put aside at weighing time and moved into the grower paddock.

Next are grower pigs which are between 30kg and 50kg. For Berkshire pigs 50kg is the magic number that once they get to they start putting on fat instead of muscle. We separate the heavier pigs into another paddock at this weight so we can provide them with a feed that matches their growth rate. Interestingly I found this same thing happened to me when I was 30 but no one put me in a new paddock to monitor my weight.

Our finisher pigs range from 50kg to 67kg. Berkshire pork has a fantastic marbling and to get this just right you need to have the perfect meat to fat ratio. We have found on our farm that this is 67kg. 70kg pigs start to get fattier and 75kg pigs are too fat for most peoples liking. To put this in perspective our pigs grow at half a kilo per day so over a week they put on 3.5kg. If we were to miss a week of weighing then the pigs that should have been 67kg are now over 70kg and starting to get too fat.

This may seem like a lot of work but we are producing the finest pork of the best breed and we want to make sure we have pork that is not too lean but also not too fatty.

We are also testing out a new device called a back fat tester. It is a small ultrasound device that quickly measures how fat a pig is so we can also base its diet based on this data. With the old shed being pulled down to make way for the new one we haven’t had much time to test this yet but we will let you know how this goes.

One of the other reasons to weigh pigs every week is to monitor their health. Once they enter the weigh crate we can get a close up view of them while they are still. If they have lost weight during the week or haven’t put on anything it can also be one of the first signs of being sick.

The other advantage of the weighing process is giving us another excuse to handle the pigs. Handling animals on a constant basis provides a relationship between you and them and creates trust so they are easier to handle and less likely to hurt you if they ever get stressed.

The string method for weighing pigs:

  1. You can purchase a tape measure designed to measure pigs from your local animal husbandry store or gather up the below items.
    • A piece of string roughly 150cm long. (If you are measuring a large pig such as a sow you will need a longer piece of string roughly 200cm long)
    • A calculator
    • A tape measure
    • Notepad and pencil
    • Feed for the pig
  1. Never try this on a pig you don’t know or trust as you need to wrap the string around the pig and it may startle them. Pigs can bite.
  2. Feed the pig and make sure she is relaxed. Take your time and start by patting and rubbing her. Once you have her trust place the string from the base of its ears to the base of its tail. Once you have this distance mark the string by tying a knot in it.Length Measurement
  3. Measure the string and record the length in metres. (i.e. 90cm = .9m)
  4. Now wrap the string around the pig just behind its front legs.

  1. Again record this measurement in metres. This is called the heart girth.
  2. To calculate the pigs weight, first square the heart girth to get the girth result.
  3. Now multiply the girth result by the length of the pig and multiply by 69.3
  4. You now have the weight of your pig in kg.


  • Betsy the Berkshire has a heart girth of 1.27 meters and a length of 1.02 meters.
  • Squaring the heart girth (1.27 x 1.27) = 1.6129 = girth result
  • Multiply the girth result (1.6129) by the length (1.02) and multiply by 69.3 = 114 Kg.


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