Korean flocks, derived from chronically infected stock (Ross 208), with both M. gallisepticum (approximately 50% seropositive by RSA test) and M. synoviae (approximately 70% seropositive by RSA test) were used in the trial. The birds were either treated with Tiamutin 0.0125% (125ppm) (2 flocks) in the drinking water for 3 days per month from week 23 to week 51 (8 treatments) or were vaccinated with a live MG vaccine at 10weeks of age by eye drop (2 flocks) or left untreated as a control (1 flock). The trial was finished at week 62. There were both MG and MS challenges during the trial from approximately week 43 according to further serological testing.
| TRIAL 3 |
Choi Hun-hi and others (2003) |
| MG and MS chronically infected flock |
| |
Ross 208
standard |
Untreated control |
MG (live)
vaccinated |
Tiamutin® (tiamulin)
0.0125% programme |
| No of birds |
- |
7220 |
13907 |
10547 |
| No of eggs/HH |
176.4 |
184.1 |
168.8 |
183.3 |
| Hatchability (%) |
85.0 |
83.2 |
83.1 |
83.3 |
| Chicks/HH |
142.5 |
147.2 |
133.6 |
146.3 |
| Hen mortality/cull (%) |
6.7 |
9.8 |
10.6 |
5.0 |
|
| No of extra chicks/HH |
- |
4.7 |
- 8.9 |
3.8 |
| No of extra chicks/HH |
- |
- |
- |
12.7 |
|
| Trial 3 |
| No. of chicks per month / HH |
 |
The untreated control flock performed very well in this study, giving improved performance results over the breed standard, except in hen mortality.
The Tiamutin-treated flocks gave positive results in chick production and hen mortality over the breed standard. In comparison with the MG live-vaccinated flocks, the Tiamutin programme of 0.0125% for 3 days/month gave 12.7 more chicks/hen housed and halved the hen mortality. As the cost of Tiamutin is approximately equal to 1.5 chicks, the return on investment is 8 times, which is highly significant in comparison with a live MG vaccine.
| 
