Swine Morsels
Swine Morsels II
Effects of ractopamine HCl on growth performance and within-pen weight variation in finishing pigs-
Published: Nov. 11, 2005
Matt R. Barker, MS; Steve S. Dritz, DVM, PhD; Mike D. Tokach, PhD; Robert D. Goodband, PhD; Crystal N. Grosebeck, MS Summary Objective: To determine if ractopamine HCl added to finishing pig diets during the final 21 days to market affects within-pen variation and growth performance. Methods: A total of 336 pigs (12 pigs per pen, 14 pens per treatment) were weighed and assigned to treatment groups (diets with or without ractopamine) in a randomized complete block design so that, within gender, mean weight and degree of weight variation were the same in each pen. Diets were based on sorghum and soybean meal and formulated to contain 1.00% total lysine, with or without 10 mg per kg of ractopamine HCl. Pigs were weighed and feed intake was measured every 7 days during the 21-day experiment to determine average daily gain (ADG), average daily feed intake (ADFI), feed efficiency (G:F), and pen coefficient of weight variation (CV). Results: In pigs fed ractopamine HCl, compared to control pigs, ADG was greater, G:F was better, and final weight was greater at the end of the 21-day trial, but ADFI and CV did not differ between dietary treatments. Implications: These findings suggest that, under the conditions of this study, ractopamine supplementation results in better growth performance and feed efficiency. The greater gain associated with ractopamine supplementation affects all pigs proportionally, with no impact on final weight variation within a pen.