I’m often asked what we feed our pigs and in what quantities, especially by people who are tempted to fatten a couple of weaners for their freezer.
There’s no “right” answer, but in general the slow growing traditional breeds require less protein at finishing than modern commercial breeds.
As we breed and finish Berkshires (early finishers) while also finishing Tamworths, Gloucester Old Spots, Saddlebacks and various cross breeds, we’ve found it’s generally better to use a sow roll with around around 16-16.5% protein or devise an on-farm mixed diet with similar levels.
But to complicate things further, it’s not really the protein level that matters – it’s the lysine to dietary energy ratio that’s important. However, while I do understand the science and how to apply it practically, most people glaze over when I start detailing how we arrive at our feed mix!
The key things to remember are that while cereals like wheat, barley and oats have lower energy levels compared to soya and fishmeal, they also have vastly lower levels of lysine (an amino acid that’s vital to building muscle).
That means their energy to lysine ratio is such that a pig fed on cereals alone will have too much energy to convert to muscle or use for bodily processes and store that as fat.
If you’re going to use own barley or oats for their diet, then you need to include higher quality proteins (such as soy beans, field beans, fishmeal or fish oil) in your mix to bump up the proportion of lysine.
If you have modern commercial pigs, then a diet that’s similar in protein and lysine levels to commercial finishing feeds will be fine.
But if you have slow growing traditional breeds, then you may need less protein so a diet that’s similar in proportions to commercial sow feeds will be needed.
Our finishers are fed half barley and vegetables to half sow rolls up to 16 weeks, one-quarter barley and vegetables to three-quarters sow rolls up to 20-22 weeks and sow rolls alone for the last two to six weeks. They also eat a lot of grass.
We’ve found it difficult to achieve consistent results over the final month unless we feed sow rolls alone—there are too many variables in feeding different types and varieties of vegetables.
We’ve also found barley fed in the last month or so makes them go to extremes of fat very quickly as the lysine:energy ratio is so poor.
In general, the finishers pigs are fed ad lib to 12 weeks, then are restricted to 1.4kg of feed a day (two feeds) up to 18 weeks.
Then they move up to 1.6-1.8kg of feed a day (two feeds) through to slaughter between 22 and 24 weeks as porkers or 26 and 28 weeks as cutters. (Slaughter ages for Berkshires.)
GOS and Saddlebacks are slaughtered from 24 to 26 weeks, Tamworths around 30 weeks but can be older as they can be more slow growing. (If the pigs weren’t on grass, their feed intake would need to be higher from 18 weeks.)
Our adult breeding pigs have various mixes of barley, vegetables and sow rolls, depending on how they’re being used, the weather, the amount of grass available to them, and their condition.
A working boar has 2.5kg a day, dry sows 2-3kg, lactating sows 5kg or more, and in-pig sows graduated amounts over their term, taking them from 3kg to 5kg or more.
Oh, and we’re aiming for around 15mm backfat, which is a a bit more than most commercial operations. It makes for very tasty pork.