Table 2 Summary of selected studies with comparators that report productivity impact (weight and egg production losses)
Cause | Pathogen (s)/cause | Number of chickens | Productivity gain | Yield reduction (%) | Reference | |
|---|---|---|---|---|---|---|
Uninfected or treated chickens | Infected chickens | |||||
Parasite | Ascaridia galli, Heterakis gallinarum, cestodes | 68 treated, 65 untreated | 65.1 g per week | 58.4 g per week | 10.3b | [33] |
Parasite | A.galli, H.gallinarum, Raillietina tetragona, R. cesticillus, R. echonobothrida, Amoebotaenia cuneata, Capillaria spp, Cheilospirura hamulosa | 50 treated, 50 untreated | 125.3 g per week | 95.8 g per week | 23.8a | [34] |
Parasite | A.galli, H. gallinarum, Cheilospirura hamulosa, R. tetragona, R. cesticillus, R. echonobothrida, Hymenolepis spp, Echinostomatidae | 40 treated, 74 untreated | 2090 g total liveweight at the end cycle (~ 18 weeks) | 1990 g total liveweight at the end cycle (~ 18 weeks) | 4.8c | [35] |
Parasite | Eimeria spp | 10 treated, 10 untreated | 99.8% weight gain | 58% weight gain | 41.8 c | [36] |
Parasite | Ascaridia galli | before (n = 800)/ after (n = 600) | 36.5% hens lay eggs | 0% hens lay eggs | 100c | [37] |
Nutritional | Vitamin A deficiency | 300 treated, 300 untreated | 91 ± 8 g per week | 53 ± 17 g per week | 41.8a | [38] |
Virus | Infectious bursal disease virus | 1618 vaccinated, 1337 untreated | 38.0 g per week | 22.0 g per week | 42.1a | [39] |