National Hog Farmer is part of the Informa Markets Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

2004 Swine Research Review


Effects of Intermittent Ractopamine Use on Late Finishing Performance

Kansas State University (KSU) research shows that if pigs are fed Paylean, taken off the product for 14 days, then feeding the product is resumed, growth performance response of those pigs is the same as if the pigs had never been fed Paylean.

Paylean, Elanco Animal Health's trade name for ractopamine hydrochloride, increases lean tissue growth and decreases fat tissue growth. Feeding the product leads to improved growth performance and leaner carcasses.

When fed Paylean, pigs respond with rapid growth rate and protein deposition within the first couple of days, then response plateaus and gradually declines over a 3- to 5-week feeding period.

Many producers feed Paylean for only 21 days before marketing because of the declining response to the product over time. However, according to recent KSU research results, when producers feed Paylean, then sell the market weight pigs, the lightest pigs left behind can benefit from Paylean, providing there is a two-week break from the product. When the product is again added to the diet toward the end of the finishing period, those lighter pigs will respond as if they had never received Paylean.

A total of 342 finishing pigs were used in a 56-day feeding trial to determine the effects of intermittent ractopamine use on pigs' growth performance in late finishing. Ninety-six gilts and 228 barrows, with initial weights in the 150-lb. range, made up the experimental groups. There were four experimental treatments with 11 or 12 pigs/pen, and seven pens/treatment.

Diets were sorghum-soybean meal-based and formulated to contain 1.0% lysine with or without 10 parts per million (ppm) of ractopamine. The four experimental treatments were:

  1. A control diet with no ractopamine fed for 56 days before marketing;

  2. Ractopamine fed for the first 21 days, then a control diet for the last 35 days;

  3. Ractopamine fed the first 21 days, then a control diet for 14 days, then ractopamine for the last 21 days; and

  4. A control diet fed for the first 35 days, then ractopamine fed for the last 21 days before market.

Pigs were weighed regularly to determine average daily gain (ADG), average daily feed intake (ADFI) and feed-to-gain ratios (F:G).

The results showed from days 0 to 21 that pigs fed ractopamine had increased ADG and improved F:G compared to pigs fed the control diet. However, from Days 21 to 35, when no ractopamine was fed, control pigs had greater ADG and tended to have improved F:G compared to pigs previously fed ractopamine (See Table 1).

During the last 21 days, and for the overall 56-day trial, pigs fed ractopamine the last 21 days of the study, or those fed ractopamine from Days 0 to 21 and then Days 35 to 56, had greater ADG and improved F:G than control pigs or those fed ractopamine from days 0 to 21.

These results indicate that feeding 10 ppm ractopamine increases ADG and F:G. The scientists say this research suggests producers may have additional options for successfully managing tail-ender pigs if they can gain benefits from feeding Paylean in a second successive group.

Researchers: Casey Neill, Robert Goodband, Mike Tokach, Jim Nelssen, Steve Dritz, DVM; Joel DeRouchey, Crystal Groesbeck and K. R. Lawrence, Kansas State University, Manhattan, KS. Contact Tokach at (785) 532-2032.

Click to view graphs.