Feed costs are currently a major burden to pig producers all around the world. Maize, wheat, rice, soy beans, and other protein crops all command very high prices and this situation seems set to continue. 

The problem is then that total feed cost per pig becomes higher than the realized farm-gate hog price. In the past, with pig price cycles there was always the expectation that in the next period, pork prices would rise again and we would be back in profit. Not so at the present time!

High costs require improved feed efficiency

With high commodity prices, there is also a shift in importance from growth rate to feed efficiency. Feed efficiency usually measured as the kilograms of feed required to produce 1 kg of liveweight growth (feed conversion ratio). Between 30 kg liveweight and 110 kg around slaughter weight modern pigs can show feed conversion ratios of around 2.5; but this varies in practice from the best performers doing 2.2 to the worst at over 3.0. Feed conversion ratio therefore is determined largely by the overall health status of the herd. 

A low (good) feed conversion ratio implies that the gut health status is also working at a high level. A high gut health status is directly related to healthy gut enterocyte cells and proper villi structure, both associated with a stable gut microflora. 

In a healthy gut system, there will be a dominance of lactobacilli and bifidus type bacterial strains, and suppression of the gram negative type bacteria such as the Escherichia coli serotypes. This allows high digestibility of in feed nutrients via the stable gut condition, and then in the small intestine there will be a high level of nutrient absorption.

Alternatives are required to secure gut health

The management of gut health therefore starts with on-farm hygiene protocols including the effective washing and disinfection of buildings and equipment. It also should include a serious look at management routines such as early weaning, all-in all-out and batch management systems. Building maintenance routines are also important.

We then consider the basic nutrition programs and especially for young growing pigs, if the formulation is wrong it leads to inadequate digestion and the transport of undigested feed material down to the hind gut. As a result it easily ferments and at the least, feed conversion ratio rises (gets worse) and at worst a serious outbreak of diarrhea and enteric disease.

Somewhere along this chain of management scrutiny we must also consider the feed additives in use. These are, in general, the array of low-inclusion feed materials that we can use that play a major role in controlling gut health status. These include the licensed medicines, but there is currently a ban in the use of growth-promoting antibiotics in many parts of the world.

The major question we have to face then is “what are the alternatives?” In theory this should be an easy question to address because there has been a tremendous volume of applied research in this area over the last 15 years. In practice, however, much of this research was carried out by the supplying companies themselves and to a large extent it has not been published in peer-reviewed scientific journals.


Additives depend on overall health status

Nevertheless, there are some basic principles of additive application that we can use ensure a cost-effective solution. The first principle is to know the farm or farm type where the application is being made. In other words – what is the health status we are dealing with? With a high health status we may need only a simple additive blend – perhaps only an organic acid blend to control the gut microflora. 

Where health status is lower there may be a need not only for an organic acid blend but also an extra help from either a prebiotic such as an oligosaccharide product or perhaps an essential oil blend. Each of these applications works in a different way and in some cases they will show synergies and positive interactions to achieve further advances in gut health control.

In Figure 1, a schematic is given to illustrate this concept. Both health status and management competence can change enormously from farm to farm and the commercial nutritionist has to make a judgment where a particular farm sits in this scheme of things. This judgment is aided by the on-farm physical performance (growth rate from 30 kg to 110 kg), the level of mortality prevailing on the farm, and the level of general drug use (clinical application of antibiotics). The use of lung scoring from abattoir data is also very valuable to define a farm’s health status.

It would also be very helpful in using such a concept on farms to provide an overall accurate health score index based on all of these parameters and this is being explored in Germany at the moment and also to an extent in the UK. Such a scoring system would be of enormous benefit to both the commercial nutritionist making on-farm decisions and the consultant veterinary practitioner giving health management guidelines.

When the status of the farm is determined, the additive or combination of additives can be assessed and applied. At the top left of the grid, as shown in Figure 1, it can be seen that a ‘simple’ diet has been allocated. This means that because the farm is so good in all respects there may be no benefit from the use of any additives. Even antibiotics have little efficacy on such farms. This highlights how a high health status brings such low cost production with it. 

At the bottom right of this grid in Figure 1, we can see that a ‘prescription’ category is allocated. This infers that these farms will only operate with the application of in-feed antibiotics. In the middle range, there is scope for applying combinations of additives (synbiotic blends). Such are various combinations of essential oils, oligosaccharides, probiotics, organic acids, and immuostimulants. Each of these additives works in a different way and can have merit on the right farms but it is also evident that some are more powerful than others. 

Cost to benefit ratio 

In the past, feed additives gave that little bit of extra performance to boost profitability. At today’s feed and raw material prices, we cannot afford any processes that may or may not yield increased profit. We must carefully judge the cost and benefit ratio for each level and type of additive. The more independent and published data we can access the easier the decision, and of course, there is nothing as good as a well-run on-farm trial. Increasingly we see a combinational symbiotic approach with certain additives.