BLACKSBURG, Va. – Paylean is the trade name of a swine feed additive produced and marketed by Elanco Animal Health. The active ingredient in Paylean is ractopamine hydrochloride, which is a member of a group of compounds classified as beta-adrenergic agonists.
These compounds have metabolic effects in growing pigs and other food producing animals including mobilization of body fat tissue and increased deposition of lean tissue.
A feed additive like Paylean is sometimes referred to as a “repartitioning agent” because it has the effect of directing energy and nutrients away from fat deposition and towards lean tissue deposition.
Original label. Paylean was approved by the U.S. Food and Drug Administration in 2000. Leading up to that approval, university and company research demonstrated that including Paylean to provide 4.5-18 grams of active ingredient per ton of feed during the late grower and finisher phases (150-240 pounds) improved growth rate and feed efficiency, reduced back-fat depth and increased loin muscle size.
In essence, the product increased lean growth rate in late phase growing-finishing pigs and the U.S. Food and Drug Administration approved label claims indicated as such. The label also included the safe use information including the fact that feeding Paylean required no pre-slaughter withdrawal period.
One caution given with use of Paylean was that pigs may be slightly more susceptible to stress during loading and transport, much like high lean genotypes of pigs are more prone to transport stress.
Because Paylean increases propensity for lean tissue deposition, it was also required that finisher pigs be fed diets with a minimum of 16 percent crude protein.
Key changes. A unique characteristic of the original Paylean approval was that, although there was no pre-slaughter withdrawal required, the product was only approved for feeding within the body weight range of 150-240 pounds.
Presumably this was due to the fact that in most of the safety and efficacy studies submitted to the U.S. Food and Drug Administration, the pigs were slaughtered at or near 240 pounds.
However, government market reports indicate the average weight of market hogs delivered to packing plants is in excess of 260 pounds.
Based on new safety and efficacy data, the U.S. Food and Drug Administration has removed the market weight restriction for feeding diets supplemented with Paylean. The new label now allows for Paylean feeding for pigs weighing at least 150 pounds body weight for their final 45-90 pounds of weight gain, regardless of final weight at slaughter.
For example if the desired marketing weight is 260 pounds, Paylean supplemented feed could be fed from a starting point of 170-215 pounds, all the way to market at 260 pounds.
Adjustment. The new label also limits the allowed inclusion rate of Paylean to be 4.5-9 grams of active ingredient per ton of complete feed with a minimum crude protein level of 16 percent. This label adjustment makes use of Paylean more compatible with typical marketing strategies for commercial hogs.
Ultimately, the decision to use Paylean will vary depending on individual production situations. Specifically, for each pig genotype and production situation, the cost of using Paylean would need to be completely covered by returns associated with improved growth and feed utilization and packer premiums for improved carcass leanness.
(The author is an extension animal specialist for swine at the Virginia Tech Tidewater Agriculture Research and Extension Center).
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