By Walter Scharlach, SPESFEED (Pty) Ltd

1. Cost-effective buying of raw ingredients

The physical inspection of a product is very important and reveals a lot about the biological quality. Bearing the cost of a truckload of a protein source in mind, it is always amazing to see that the material is hardly ever inspected and virtually no attention is given to quality.

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The application of our nutritional knowledge in practice is by means of a simple mathematical technique called linear programming (LP). Apart from providing a simple formulation, LP gives the formulator much valuable economic information about the proposed formulation by giving a reduced cost or shadow price for each limiting nutrient. This figure represents the amount by which the cost of the feed would be increased or decreased if the minimum constraint were to be increased or reduced by one unit, or until the next change in value. In a similar way reduced costs and ranging values are also generated for the ingredients that are used in the formulation. These costs represent the amount by which you are over or under paying for an ingredient, or the price at which an ingredient will be accepted or rejected.

In essence feed formulation consists of two components, namely the animal itself and the ingredients which make up its diet. The complex set of interacting factors which need to be considered when formulating diets mean that considerable experience needs to be built up if the formulations that are produced are to be optimal. These are best illustrated by means of Figure 1.

Alternative ingredients : Pigs do not require specific ingredients in their diet, but instead require energy and nutrients such as, amino acids, fats, vitamins and minerals. Under commercial conditions the choice of feed ingredients should be based on economic considerations.

Genotype and Productivity : The animal’s ability to deposit lean tissue is the area in which the most genetic improvement has been made. This means that the dietary levels of protein and energy have increased over time, with a faster rate of increase in amino acids relative to energy. No matter how high the genetic potential for growth is, the environmental and management conditions under which the animals are kept may prevent them from exhibiting their true potential. If feed intake is the limiting factor one will often see an improvement in performance if the nutrient density of the diet is increased. On the other hand if the health status and general management of the animals is very poor, little is achieved by feeding diets high in protein and energy. The recommended daily nutrient allowance should be designed on the specific genetic potential for lean tissue deposition within the limitation of the commercial farm environment.

Health : An animal’s health status may impact upon its nutrient requirements in one of two ways. Firstly, sick animals often go off their feed or are simply not strong enough to eat. Secondly, when animals are exposed to antigens (substances foreign to the body), the body mounts an immune response. This entails the formation of proteins (immunoglobulins) which not only contain high levels of amino acids but also require energy in their formation, so directing these nutrients from production. It would appear that if disease reduces the lean deposition potential a lower density diet will become more cost effective (Dalgety Yearbook, 1998).

Economics : When formulating the diet the nutritionist uses nutrient requirements that satisfy the objectives of the entrepreneur, whose aim is to find the level of inputs which will maximise the difference between the value of the output and the cost of the input.

Feed Intake : The task of translating a recommended daily allowance into a feed specification is further complicated by the fact that animals do not have an unlimited capacity to consume feed. This capacity is influenced by many factors, including the nature of the feed itself, the animals size, level of production and physiological state at any given time. Many factors affect feed intake and include issues such as access to feeders, feeder design, overcrowding, high temperatures and health aspects.

Producing the optimum diet : The major limitation of LP is that it does not take the curvilinear response of a population of animals to nutrients into consideration. Thus in order to derive diets which will maximise profitability of the feeding operation it may be necessary to carry out series of formulations each at different levels of nutrient input. The optimum diet will maximise the margin over feed cost. In order to determine what the nutrient density of a diet should be it is important to know how pigs would respond to different levels of feed energy. In table 1 the response of growing pigs to dietary energy is shown:

Pork currently costs 5 times more than feed. Any dietary change that reduces the cost of feed by 5% can only be cost-effective if the output of pork is reduced by less than 1%. In table 7 the dressing percentage was reduced by approximately 2.5% between the low and high energy diet, resulting in a vastly reduced margin on the lower density diets.

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Multi mixing : When single mix formulations are carried out it is assumed that all ingredients are freely available. In most commercial situations this is not the case and we are able to use a multi-mix to solve the problem. A multi-mix considers all of the products that are to be manufactured, together with the expected tonnage to be manufactured, and all of the available ingredients. A multi-mix program allocates restricted raw materials to those feeds in which they are most cost effective. For example, if the quantities of fishmeal are limited, it is usually allocated for use in a weaner diet rather than in a finisher diet. It must be remembered that should your stock holding of maize be at R 750.00 and the market price goes up to R 900.00, the maize that you hold in stock is a "limiting" raw material.

Nutritionists working in the broiler industry have studied phase feeding to get the optimal number of diet transitions for improved production efficiency. With growing pigs there is beginning to be similar emphasis evaluating increased number of diets during the grower-finisher phase. Traditionally a grower diet is used from 30 to 55kg and a finisher is used from 56 kg to market. Figure 2 shows why step feeding is wasteful.

Research at the University of Kentucky (1992) has evaluated the effect of two and three phase-feeding programs on performance and carcass composition. This is shown in table 2 below:

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Table 2: Comparison of traditional Two-phase versus Three-phase feeding program on market pig performance and carcass composition (Central Soya Feed Research, 1992).

Separate sex feeding : Sexes differ in lean growth and feed intake. Boars have the highest lean growth, barrows have the lowest lean growth with gilts being intermediate. Compared to gilts, barrows consume approximately 8% more feed. The higher intake and lower lean growth potential reduces the dietary amino acid specifications for barrows by approximately 10%. Penning barrows separately from gilts and feeding them different diets is thus a method of saving feed costs.

Separate sex feeding and multiple phase feeding during the grower-finisher period more closely match the pig's nutrient needs and improves efficiency of lean gain. Excessive amino acid intake, especially during the finishing phase can impair performance. This depression is due to the physiological burden of processing and eliminating extra protein consumed above the pig’s biological needs. It can be concluded that multiphase diets, if properly fortified and sequenced, will increase growth rate, lower feed cost, improve feed efficiency and may improve carcass quality.

Proper grinding is an effective way to ensure optimum performance of pigs (Giesemann et al.1990, Wondra, 1995). The finer particles result in an increased exposure to digestive enzymes. Hancock (1999) reviewed several experiments and reports a 1.3% improvement in feed efficiency for each 100–micron reduction in mean particle size when growing pigs fed maize particles from 1200 to 400 micron. Table 5 shows some work that was done on lactating sows at the Kansas State University. This work suggests that the optimum particle size for cereal grains is 600 micron or less.

 

5.    Ensure consumption by the pig

Investigators in Australia estimate that 10 –15% of all the feed used on grower/finisher farms is never consumed by the pig (Hutson, 1997). Feed is primarily wasted as follows:

Direct wastage : When feeders are too full, pigs paw or root the feed out. The mechanical adjustment and repair of feeders should therefore be a daily management priority. A standard rule is that 50% of the self-feeder trough bottom should be visible.

Indirect wastage : During the cause of normal eating most pigs do not finish chewing the feed until standing or walking away from the trough. This results in feed spillage from the mouth unto the floor. Video recording in Australia has shown that some pigs visit the feeder far more frequently than the calculated minimum of 17 meals per day. The average visits to the feeders where 62 times a day with some pigs coming to the feeder 170 times. This problem can be addressed by better feeding design that promote fewer but longer mealtimes by increasing the "work" of obtaining feed.

Dust loss : Dust may be of much greater significance than often realised. The dust contributes to the atmospheric dust load which, increases the prevalence of respiratory disease and further reduces productivity.

Each of these elements can reduce the cost of pork by either improving feed efficiency and/or pig performance. Most farms should be able to improve on one or more of these factors and achieve a significant improvement in production cost.