|Neill, Casey -|
|Goodband, Robert -|
|Tokach, Michael -|
|Nelssen, Jim -|
|Dritz, Steve -|
|Derouchey, Joel -|
|Groesbeck, Crystal -|
Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 5, 2010
Publication Date: March 16, 2010
Citation: Neill, C.R., Goodband, R.D., Tokach, M.D., Nelssen, J.L., Dritz, S.S., Derouchey, J.M., Groesbeck, C.N., Brown, K.R. 2010. Effects of intermittent ractopamine hydocloride use on pig growth performance in late finishing. Professional Animal Scientist. 26:239-242. Interpretive Summary: Ractopamine hydrochloride (RAC) is used as a feed additive to promote increased average daily gain and improve feed efficiency in pigs when fed 2-4 weeks before market. Pigs below market weight at the time of harvest may be moved to a different facility until ready for harvest or combined with a different group of lightweight pigs. Under many circumstances, these lightweight pigs may be fed a diet containing RAC for a short period of time and then be refed RAC once they are closer to the desired marketweight. Currently, there is limited data on dealing with RAC withdrawal and refeeding in swine.
Technical Abstract: Two experiments were conducted to evaluate the effects of feeding, withdrawal, and refeeding 10 ppm ractopamine hydrochloride (RAC) on pig performance. In Exp. 1, the 4 treatments consisted of 1) a control diet fed for 56 d before marketing; 2) RAC fed for the first 21 d, and then the control diet fed for the last 35 d; 3) RAC fed for the first 21 d, the control diet fed for 14 d, and then RAC fed for the last 21 d; and 4) the control diet fed for the first 35 d, and then RAC fed for the last 21 d. Pigs fed RAC for the last 21 d of the study or those fed RAC from d 0 to 21 and then from d 35 to 56 had greater (P < 0.01) ADG and G:F than control pigs. In Exp. 2, the 5 treatments consisted of 1) a control diet fed for 56 d; 2) RAC fed for 56 d; 3) RAC fed for the first 21 d, the control diet for fed for 14 d, and then RAC fed for the last 21 d; 4) the control diet fed for the first 7 d, RAC fed for 21 d, the control diet fed for 7 d, and then RAC fed for the last 21 d; and 5) the control diet for the first 35 d, and then RAC fed for the last 21 d. When RAC was fed for 21 d and then withdrawn for either 7 or 14 d and refed for 21 d, the pigs had the same overall ADG and G:F as those fed RAC for only the last 21 d of the study.