Dunbia Farmers 12/2010

Feed conversion efficiency (FCE) is one of the main yardsticks to measure the performance of finishing pigs.It is defined as the number of kilograms of feed required to produce one kilogram of liveweight gain.

Factors influencing FCE

• Feed wastage

• Stocking rate

• Slaughter weight

• Disease

• Environment

Feed wastage

The daily feed intake per pig takes account of both the feed consumed by the pig and also of feed wasted. It is essential to eliminate wastage as far as possible. Among the factors which contribute to feed wastage and therefore feed efficiency are worn feeders, faulty feeders or trough design, excessive feed allowances and accumulation of stale feed in hoppers.Stocking rateOvercrowding of pigs is likely to reduce daily feed intake, especially if large competition for feeders, which will decrease growth rates along with a deterioration in FCE. Table 1 shows recommended stocking densities for different weights of pigs.

Table 1: Recommended stocking densities in the Canadian Code of Practice (Patience, 1997)

Body Weight (kg/pig) Floor space (m2/pig)

25 0.33 50 0.53 75 0.70 100 0.85

Slaughter weight

As slaughter weight increases, FCE in finishing pigs deteriorates. Results

of experimental work carried out by B Lynch, Moorepark suggests that on average a 1 kg increase in slaughter weight (live) results in a deterioration of 0.01 in FCE.

Disease

The effect of disease on FCE will vary depending on the severity of the disease, herd size,

the influence of environmental factors, level of immunity in the herd and management practices.

The following table gives an estimate of the effect diseases has on FCE.

Feed Conversion Efficiency of Pigs

Dunbia Farmers 12/2010

Table 2. Effect of diseases on FCE

Disease Percentage reduction in feed efficiency

Haemophilus pneumonia 7 Mange 6 Atropic rhinitis 7 Swine dysentery 9 Enzootic pneumonia 8 (Source: NI Department of Agriculture 1987).

Environment

Temperature is the single most important environmental factor affecting pig performance. There is a critical temperature band within which pigs perform at optimum efficiency. If above or below this temperature range, feed efficiency deteriorates.Cold draughty houses which result in the effective environmental temperature being below the critical temperature of the pig, adversely affects feed conversion efficiency. Good quality housing with accurate and reliable environmental control need only produce relatively small improvements in FCE to justify the extra cost over lower quality housing.

Breeder herd

The productivity of the sows and the breeding policy of the unit affect the amount of breeder feed per pig marketed. If the number of pigs sold per sow per year is reduced by 10%, sows will consume 10% more feed per pig sold. This will increase the breeder feed by about 6kg per pig sold, increasing feed costs and reducing farm profit.

Grower herd

The biggest overhead on a pig farm is the daily maintenance requirement, which uses feed but generates no saleable product. As the maintenance portion is mainly a function of live weight, it becomes clear that a slow down in growth rate towards the end of the growing period will invariably reduce feed efficiency. High growth rates reduce days to an end slaughter weight minimising days on feed and associated costs.

Temperature

Fast growing pigs are very sensitive to high temperature especially during the last month of growth. A 1OC increase in temperature above the comfort temperature will reduce feed intake and hence growth by 30g. This is shown in Table 2.

Table 3: Effect of temperature on growth performance of pigs (Ohio, 1991)

Temperature (°C) Growth (g/day) FCR (g/g)

10 800 4.38 20 850 3.79 30 441 5.02

Fatness

The synthesis of fat requires approximately 3.5kg feed per kg of fat, in comparison to lean tissue which requires 1.25kg feed per kg of lean (Whittemore, 1993). Consequently animals finished to high levels of fat cover will invariably have a reduced feed efficiency.

Feed Wastage

Recent work has shown that the average Australian pig farm wastes approximately 10% of bought in feed. The local figure for feed wastage may be similar. The mechanical adjustment and repair of feeders should therefore be a daily management priority. A standard rule is that about 50% of self-feeder trough bottom should be visible. Trough bottoms that are completely covered with feed are probably wasteful.

Loss in Protein deposition

A pig's genetic merit is determined by its ability to deposit lean meat. Lean deposition follows a rainbow-like curve. For improved animals the lean deposition may peak higher and decline slower. Any decline in lean meat deposition during the finishing stage reduces feed efficiency

Conclusion

The breeding herd consumes about 20% of total farm feed and is therefore a relatively small contributor to feed efficiency. Poor feed efficiency is almost always caused by the finishing pigs. Due to the high cost of maintenance feed, fast growth rate is of utmost importance. It is important to ensure that there is no slow-down in growth towards the end of the growing cycle. To maximise farm profits, a high level of feed efficiency is essential in contrast to increasing animal numbers and "Cramming" pigs through an inefficient growing/finishing facilities which will only add cost and decrease profitability.

For more information please contact the following: Dr Elizabeth Ball (not the author of this article). E-mail; Elizabeth.ball@afbini.gov.uk; Tel. 028 9268 2484

Dunbia Farmers 12/2010

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