Results of a second Pork CRC-supported study at Department of Agriculture and Food Western Australia (DAFWA) Medina, WA research station, established the responses of pigs between 50 and 100 kg to dietary lysine.

The study, managed by DAFWA's Karen Moore, showed both sexes exhibited excellent performance and the results further demonstrated the high performance capabilities of modern Australian genetics. Males grew 10 per cent faster and were 14 per cent more feed-efficient than females. The latter differences are evident from Figures 1 and 2, which show the responses of the two sexes to dietary lysine between 50 and 100 kg.

Figures 1 and 2 show the effects of dietary available lysine on the growth rate and feed: gain of male and females female pigs between 49 and 103 kg live weight

Results for the period 50 to 100 kg suggest the two sexes respond similarly to dietary lysine in terms of growth rate, but males have a higher requirement to minimise feed:gain.

However, when changes in feed efficiency and growth rate are viewed over a wide range of live weights, it appears that for the genetics involved, 0.50 to 0.55 g available Lysine:MJ DE would maximise growth rate and feed efficiency of females between 50 and 100 kg. For males, 0.60 to 0.65 g available Lysine:MJ DE would be required to ensure maximum performance over the same live weight periods, but the level of available lysine could be reduced to 0.50 g available Lysine:MJ DE at 80 kg live weight.

Ms Moore's report provides much more detailed information and response curves and the estimated requirements for pigs from 20 through to 100 kg and producers should ensure their nutritionists are aware of the results and let them decide on the implications and most cost-effective strategies for individual situations.

Obvious outcomes from the studies are that the sexes differ in growth performance and requirements as early as 20 kg, with males eight to 14 per cent more efficient than females, with the difference increasing with weight. Between 20 and 50 kg, however, males eat less and grow slower than females. This difference is reversed after 50 kg.

There are, however, subtle changes with weight/time and females are more sensitive to an oversupply of amino acids than males at heavier weights, so all the data needs to be considered in establishing the most cost-effective strategies for different businesses.

Further Reading

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You can view the full report by clicking here.