Using Stafac® to improve performance in grow-finish pigs during the summer heat

The heat of the summer makes it extremely difficult to keep pigs performing at an optimal level. Keeping the animal comfortable during periods of high heat is very important to help minimize economic losses. The feed additive virginiamycin, more commonly known as Stafac®, may help grow-finish pigs perform closer to their optimal levels during the summer months. During the 2006 Allen D. Leman Swine Conference, B.R. Gramm and R.D. Nimmo of Phibro Animal Health and G.L. Allee of the University of Missouri presented a research report on the effects of virginiamycin on performance of heat stressed finishing pigs. The study was conducted in the Brody Climatology Chambers at the University of Missouri.

Materials and methods

Seventy-two finishing pigs (TR-4 x C22) weighing approximately 200 pounds were randomly assigned to treatment and environmental groups in a 2 x 2 factorial design. Gramm et al. said a total of six replicate pens of pigs (three pigs per pen) were fed diets containing Stafac at 10 g/ton or no Stafac and exposed to thermoneutral or cyclic heat stress conditions in environmental chambers. The thermoneutral chamber remained at 73.4 degrees F for the 28-day study duration. Temperatures in the heat stress chamber cycled between 98.6 degrees F (11 a.m. to 7 p.m.) and 80.6 degrees F to mimic fluctuations found between daytime and nighttime temperatures.

Results and discussion

The heat-stressed environment had a significant effect (P < .05) on feed intake, weight gain and feed conversion. All three metrics were negatively impacted by heat stress (see table above). Stafac tended to improve (P=.09) ADG in both the thermoneutral and heat-stressed environments. Stafac did not impact feed intake in either environment. As a result, the study showed significant improvement (P<.05) in Feed/Gain for Stafac-fed pigs in both the thermoneutral and heat-stressed environments. Gramm et al. concluded that virginiamycin can help maintain growth performance in heat-stressed finishing pigs. This benefit most likely results from the antimicrobial activity of virginiamycin positively affecting the gut microflora and reducing heat increment in pigs, especially during periods of heat stress. Contact your Vita Plus representative for more information about Stafac and other feed additives that may help maintain performance during the summer. Reference:  Gramm, B.R., R.D. Nimmo, G.L. Allee. 2006. Impact of Stafac (Virginiamycin) on performance of heat-stressed finishing pigs. Proceedings 2006 Allen D. Leman Swine Conference. pp. 25.

About the author:  Spencer Jones joined the Vita Plus team in 2011 and works as a swine technical sales consultant.  He received both his bachelor’s and master’s degrees in nutrition from Kansas State University.  Jones grew up showing hogs and steers for 4-H and working on a beef feedlot.  He is a member of ASAS, American Angus Association, Iowa Angus Association and Iowa Cattleman’s Association.  Jones lives in Iowa with his wife of four years, Cassie, and their son, Ty.