The Feeding Herd - "Hidden Costs"

Author: Mark White BVSc LLB DPM MRCVS
Reviewed: Mark White BVSc LLB DPM MRCVS 2016
Published: 2005

Lack of recording in the breeding herd has been previously highlighted as a fault of many pig farms currently in that problems - particularly of fertility and production -cannot be properly investigated without them.

As a general finding, record keeping in the feeding herd is even more sparse on most herds.  Accurate growth data is costly - in terms of time - to generate; feed efficiency data - one of the most significant measure of production cost in growing pigs - is usually only accurate on a herd basis if measured over a prolonged period of time (e.g. 6 months) and, therefore, gives little indication of variations or efficiency of feed usage in any particular age group.  For most farms, the measure of feeding herd efficiency is the mortality rate and abattoir returns giving weight and grade data. The increasing application of batch systems whether they be in continuously occupied sites or on an all in all out basis make feeding herd performance measuring more straightforward but many farms still lack key performance indicators.

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Mortality is easily measured but where disease occurs that increases mortality, the cost of lost growth/poor feed efficiency is often much higher.  As an example, an outbreak of Swine Dysentery may increase mortality by 5% in growing/finishing pigs costing £3000/1000 pigs affected.  However, feed efficiency will decline by 0.5 or more, more than doubling this cost.  Slowed growth may lead to reduced finishing weight (if space is fully utilised) with further cost penalty.

However, there is another cost associated with disease that producers do have data for but frequently fail to make full use of.  That is the issue of condemnation at slaughter.  A full carcass condemnation equates to an on farm death with a premium as a result of transport costs and inflated disposal costs at the abattoir.

Condemnation rates from farms vary considerably.  Many will average below 0.02% i.e. less than 1.5kg on a consignment of 100 bacon pigs.  In others, it has been reported to be as high as 1% - equivalent to one whole carcass per batch of 100 pigs.  (These figures ignore condemnation of offal, which do not contribute directly to the payment).  The common areas of condemnation are part legs (anything from 2-20kg), skin (6kg), head (6kg), chest wall (10kg+) and whole carcass (c80kg). Such condemnation may also lead to downgrading with further penalty not only on that carcass but potentially on the whole batch if it pushes the group below the premium threshold (typically 85% in the top grade)

The main ailments that occur on farm which are associated with carcass condemnation are:-

1) Erysipelas causing skin and leg rejection.

2) Tail biting causing multiple abscessation throughout the body and leading to whole carcass rejection (usually listed by meat inspectors as Pyaemia).

3) Septic pleurisy and pneumonia causing chest or whole carcass condemnation - usually resulting from complex bacterial infection including Glassers Disease, Pasteurella etc.

4) TB lesions in head lymph nodes (leading to head condemnation).

5) Injuries and wounds to lower limbs leading to trimming.

An interesting observation from one large unit which sold pigs to 2 separate outlets was the difference in condemnation rates.  With pigs allocated to the 2 outlets on a random basis, measured over a year, the condemnation rates from 1 outlet was 3 times that of the other. In both plants the monthly condemnation rates varied considerably. Where condemnation rates exceed 0.2% of the total batch weight full investigation is necessary, particularly if it is regularly repeated

Since 2005 detailed reports have been available to all producers, generated by experienced veterinary surgeons undertaking abattoir inspections in the form of the British/BPEX Pig Health Scheme (BPHS). These reports quantitatively identify damage within the pig to the red offal (heart, lungs and liver) which may not be evident in the live animal but which contribute to lost performance. Unfortunately, the data for only 50% of the pigs slaughtered is requested back on farm and utilised meaning many farms are ignoring useful information. Examples of these hidden costs are

  • An SEP lung score of 5.5 equates to a loss of growth of 40gm/day between 30 and 100 kg giving and extra 4 days to reach slaughter weight requiring an additional 6.5kg of food in maintenance - a cost of £1.30/pig
  • Pleurisy (inflammation and scaring outside the lungs) rates of 15% are commonly seen. These can have the effect of reducing carcass yield by up to 1.5kg at a cost of £2/carcass
  • It has been claimed that milk spot in 25% of livers if severe can be associated with a loss of growth of up to 10% of the whole group equating to a cost of £3 per pig in additional feed cost

Unfortunately, at the time of writing (2016) health reports generated at the time of meat inspection under the CCIR system have not been shown to reliably represent the true picture and are of little value. It is expected by the pig industry that in time that data collection generating these reports will be improved and ultimately become a substitute for BPHS

A final element of loss that producers rarely take note of is killing out percentage, which, again, can be highly variable.  The above unit mentioned also measured a difference of 0.7% killing out percentage over a year between the 2 abattoirs - rather bafflingly the higher yield being produced from pigs travelling the greater distance.  In this case, the higher yield came from the abattoir with the higher condemnation rate acting as something of a counter-balance.

The point of these notes it to highlight that there is a rich source of usable data available for the feeding herd, which is frequently ignored.  Killing out percentage can have a dramatic influence on returns (yields ranging from 73% - 76% for a 80kg carcass are reported) and, only if such information is collated, can it be used to improve output from the farm.


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