In defence of long troughs

Extremely wet conditions in the second half of 2012 raised question marks about the concept of long troughs. John Harvey, of John Harvey Engineering who addressed a BPEX meeting in April set up to discuss the issues, considers the problems and how they were addressed

Back in 2007 Suffolk farmer Barry Crick approached me and said he wanted a pig trough to feed by-product. It needed to be long so the sows couldn’t easily move it about and they had room to move to a new position if they were bullied; and it had to be wide so he could feed the by-product by machine. As the troughs would also need to be easy to move from site to site, we settled on a length that could be carried on a straw trailer.
Once the troughs were in place it was noticed that there were no birds on the site. I suggested to BQP that this could be a way to reduce bird numbers and reduce feed losses, especially where feed was quite dusty and the dust would be lost, and trials to test this theory began in 2009.
In early 2010 BQP secured funding from a wide range of organisations and individuals to set up its Eco Project. A combination of long troughs and farrow feeders were used in this trial, and in the first two years of the three-year project, an overall reduction in feed costs of 15% was recorded.
Eco Farm manager David Robinson, who was the principal designer of the farrow feeder, also noted: a reduction in the problem bird population; more even soil nutrient levels; easier animal management and pregnancy testing; faster feeding; and better condition of sows at weaning.
Meanwhile, I started production of long troughs and supplied them 4m, 6m and 7.5m long, with the option of drain hole sizes to suit specific soil types and ground hooks for existing paddocks where the uneven soil allowed the troughs to pivot and move about easily or on stony soil where troughs would easily slide. Farrow feeders were also offered either as stand-alone units on a chequer plate plinth for easy movement around the paddocks or attached to drinker troughs.
All went well until late last summer when the rain came and didn’t seem to stop. Total rainfall for 2012 was near double the average rainfall in some areas, and this presented serious problems on some farms. Typical of the problems experienced were:

  • excessive mud in the troughs that couldn’t drain out as the drain holes were under mud;
  • the 3mm feed mixed easily with the mud and caused excessive soil ingestion;
  • the 3mm feed stuck to the animals’ legs;
  • where there were problems getting the feed accurately in the trough, the sows dug around the trough and ingested more soil;
  • there was an increase in the variability of sow condition;
  • there was excessive soil compaction in the track ways;
  • vermin increased where there were problems getting feed in the troughs;
  • there was a perceived increase in sow mortality; and
  • sows were crowding at the start of feeding (which wasn’t necessarily because of the wet weather).

Sow deaths
While investigations of increased sow deaths showed the numbers were actually no greater than peaks in previous years, I was still interested in why this was happening. One suggestion is that it was a gut-fill issue related to the type of diet. Some farms reported low sow mortality but an increase in sows eating fresh barley straw bedding, so the problem could well be related to the low bushel weights last harvest as monogastric animals are not good at digesting low-bushel-weight feed.
The first step to address the problems being experienced was to drop the cheaper 3mm feed being used with the long troughs and go back to feeding rolls in the troughs throughout the wet weather. Apart from being more expensive, the problem with rolls is that putting them in the troughs can be noisy and this acts like a dinner bell for birds. More experimentation into feed is underway and this will hopefully result in a relatively dust-free form, probably 6mm in size. Although it may still be necessary to return to rolls during wetter weather.
The other main change has been to lift the troughs onto wood blocks so that the drain holes can work. This keeps the troughs free of mud and the sows don’t tend to walk in the trough, which allows the feed wagon to put the feed where it needs to go. This adaptation has been highly successful on sites where mud has been a serious issue. Our troughs come in a single-formed construction, so raising on two blocks is no problem, and where this has been done vermin have gone and some of the most ardent detractors of troughs have converted to supporters.
Another development I’ve looked at is aimed at reducing compaction in the track ways. Here, an adjustable spout on the feeder wagon can be used so that the operator isn’t restricted to one track. Various types are already available, and the whole subject of how the feed is distributed is worth an article in its own right.
Farmers who are now getting on well with long troughs are reporting feed savings of up to 0.5kg/sow. Together with a reduced cost feed for all but the worst months, this gives a significant saving. Problem birds are also reduced on fully troughed units, and feeding time has been reduced. Farrow feeders have also worked well with reports of greatly improved sow condition at weaning.

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