157
The effects of feeding narasin or virginiamycin on growth and harvest performance of pigs during the grow-finish period
The purpose of this study was to determine the effects of narasin (NAR; Skycis®, Elanco Animal Health, Greenfield, IN) or virginiamycin (VIR; Stafac®, Phibro Animal Health, Teaneck, NJ) on the growth and harvest performance of pigs during the grow-finish period. On day -7, seventy-two pens each containing 8 pigs with a BW of 23.4 kg were blocked by weight within gender and then treatments: control (CON), NAR 15 ppm, or VIR 11 ppm were randomly assigned to pens within gender of each block. Diet treatments consisted of a sequence of five pelleted diets containing corn, soybean meal, and DDGS with the appropriate amount of antimicrobial premix added identical diets within of the five phases. Pigs were weighed on d 0, 28, 56, 76, 97, and 108 to determine initial weight, phase weights, and ADG. Feed issuance and weigh backs were recorded in order to determine ADFI and G:F. When pigs reached a BW of 127.4 kg, they were transported to a food company for harvest. HCW, fat depth, and loin depth were measured on each carcass. During d 0 to 28, ADG and ADFI of pigs fed diets containing NAR or VIR was greater (P<0.05) than CON. During d 28 to 56, pigs fed VIR had a greater ADG and ADFI than those fed CON (P<0.05, and tended to have a greater ADFI (P<0.1) than those fed NAR. Pigs fed NAR had a greater (P<0.05) G:F from d 0 to 28 than pigs fed CON or VIR . From d 0 to 108, pigs fed NAR had a greater (P<0.05) G:F than those fed CON, and tended to be greater (P<0.10) than those fed VIR. Pigs fed NAR and VIR (P=0.0051) had a greater (P<0.05) carcass yield than those fed CON. In conclusion, pigs fed NAR or VIR for the entire grow-finish period have greater carcass yield than those fed control, and pigs fed NAR have a greater G:F than those fed CON.
Item |
CON |
NAR |
VIR |
SE |
NAR vs CON, P< |
VIR vs CON, P< |
NAR vs VIR, P< |
ADG, d 0 to 108 |
0.955 |
0.968 |
0.965 |
0.007 |
NS |
NS |
NS |
ADFI, d 0 to 108 |
2.340 |
2.345 |
2.374 |
0.02 |
NS |
NS |
NS |
G:F, d 0 to 108 |
0.398 |
0.408 |
0.400 |
0.003 |
0.05 |
NS |
0.10 |
Keywords: Narasin, Virginiamycin, pig