Now that I have finished the sausages and bacon, I have been able to put together some measurements and weights specially for you, Kitchen Cottage, as it was you who introduced me to the Berkshire chart earlier this year and I have been using it since, as last year's pigs were far too fat in my opinion.
I have Tamworths and Saddlebacks, they live in woodland although they have little undergrowth left to eat, and are fed ordinary 16% nuts all the way through from weaning to slaughter, and as per the chart, are now getting 1.93 kgs each per day as oppose to approx 2.2 kgs each last year. They are wormed and have ample space to move around, although in the torrential rains of this year they spend far too much time inside doing nothing. Occasionally they are fed fruit and veg instead of nuts, at a replacement rate of 4 veg: 1 nuts.
Last Monday we sent the largest SB and Tamworth gilts to slaughter aged 28 weeks, they both came back with 19 mm fat, a good improvement on last year, and their deadweight was 69.8 kgs and 62.7 kgs respectively.
We do our own butchery and about half our pork joints are boned and rolled, the rest not, and all the surplus bones, spare fat and skin, trotters and head almost always go into the waste pile. For the Saddleback we ended up with 42.6 kgs of meat, 9.5 kgs of sausage meat, 15.6 kgs of waste and 2.1 kgs unaccounted for. The Tamworth produced 42.6 kgs of meat, 3.6 kgs sausage meat, 5.1 kgs head meat and fat for brawn, 8.8 kgs of waste and 2.6 kgs unaccounted for.
I also have some tape measurements for these two (G for girth and L for length, in metres), although the length measurement is questionable, mostly too long, as I can only do them when they have their heads down eating, which makes the length anything from 6 to 10 cm longer than if they have their heads up. I have used the formula G x G x L x 69.3 to estimate their live weight:
26 weeks: SB G 1.02 L 1.22 Wt 87.96 kg Tam G 0.99 L 1.17 Wt 79.47 kgs
27 weeks: SB G 1.03 L 1.24 Wt 91.16 kg Tam G 0.99 L 1.19 Wt 80.83 kgs
28 weeks: SB G 1.04 L 1.28 Wt 95.94 kg Tam G 1.02 L 1.22 Wt 87.96 kgs
As I said, all these measurements have to be taken with a pinch of salt, particularly due to the inaccurate lengths, but if you multiply these by 0.72, you end up with dead weights close to what they actually were. Nevertheless you will see that they hardly changed shape at all over this fortnight, and there doesn't seem to be anything to suggest a growth spurt in terms of their tape measurements.
For comparison, our two Tamworths last year were slaughtered at 30.5 weeks and dead weights were 75.1 kgs (gilt) and 84.3 kgs (boy), but their fat levels were 24 and 29 mm respectively. The Saddlebacks were slaughtered at 31.5 weeks and their dead weights were 77.8 kgs (gilt), 82.7 and 87.4 kgs (2 boys), with fat levels of 28, 25 and 24 mm respectively. So both heavier but also far fatter. The reason these pigs were slaughtered 3 weeks later than this year's is that they just didn't look big enough at the time, but with hindsight this was probably a mistake, especially if all all they did in those last 3 weeks was put on extra fat rather than extra flesh.
Two things I should like to point out, just to make matters even more confusing. None of our pigs, this year or last year, seemed to be remotely over-fat to us while they were alive, despite the fact I have never been able to "feel" the backbone on any of my pigs, even when they are as young as 4 week old pre-weaners. They all look to me, this year and last, long, lean and quite normal sized. It is all very well saying "feed by eye", but I don't think there is really that much scope for changing their weights/fat significantly in the last 3 or 4 weeks - one needs to have a programme to work to for a whole season, and if that doesn't produce the results, try a wholescale lower or higher feeding regime for the next batch of pigs.
The other thing that is significant is that within any one litter of pigs, the same breed, fed exactly the same amount from birth to slaughter, there can be as much as 10 to 15 kgs difference in their final dead weights, so there are other factors at play as well as how much they are given to eat. Like chickens, there is definitely a pecking order amongst pigs, and some of them never compete as well as their siblings for the available grub and end up much lighter at the end.
This data has been taken from my copious spreadsheets I have here, so if you want any further detailed info, do get in touch. Do hope this has been of some help; I too like to know how much goes in and also what you get out of it in the end, rather than relying on intuition alone as mine is just not that good. Tamsaddle
Topic: Pigs and weight gain (Read 12772 times)
