Table 1.
List of the model parameters.
| Parameter | Definition | Value and Unit | Reference |
|---|---|---|---|
| Feeding duration | Total duration of the fattening period | 36 days (Ross 308) 47 days (Rowan x Ranger) |
[21,43] |
| Feed intake | Daily feed intake for all days of the defined fattening period according to the information provided by the breeder | According to manual [g] | Aviagen manual Ross 308 [44], Table “As-Hatched Performance”, days 2–37; Aviagen manual Rowan Ranger [45], Table “As-Hatched”, days 2–48 |
| Water intake | Daily intake of water for all days of the defined fattening period according to the information provided by the breeder | According to manual [g] | [46]; 70% of the quantities, see manual Aviagen Brief [47] |
| king | Litter uptake and intake of ESBLs with contaminated litter | Factor 0.014 (= 1.38% of the amount of feed intake [g]) | Estimated [42] |
| Litter amount | Litter quantity per square meter at the beginning of the fattening period | 1000 g/m2 | Commercial standard in Europe |
| Stocking density | Maximum number of chickens per square meter (refers to the target weight) | 39 kg/m2 | (Tierschutz-Nutztierhaltungs-verordnung—TierSchNutztV), 2001, § 19, Absatz 7, (3) |
| kvia | Random factor for bacteria which do remain capable of reproduction when ingested | 0–0.5 | Assumed |
| kgro | Random growth rate for ESBL-producing E. coli in the chicken’s intestine | 100–105 | Maximum estimated [48] |
| Carrying capacity | Maximum number of CFU ESBL-producing E. coli in colon | 8 log10/g | [49,50] |
| Transition factor | The factor by which the total amount in the chick within 24 h, 1 day, has to be divided to obtain the content of the intestine (in grams) | 4.85 | Transition time estimated [51,52,53] |
| kexc | Factor of excreted bacteria | 0.3 | Assumed |
| ksur | Daily survival rate of ESBL in litter | 0.5 | Estimated [31,54] |
| Target weight | Weight of the chickens at the end of the fattening period (see “feeding duration” above) | 2.332 kg (Ross 308) 1.911 kg (Rowan x Ranger) |
Aviagen manual Ross308-308FF-Broiler [44], Table “As-Hatched Performance”. Aviagen manual Rowan Ranger [45] (Appendix 3, Table 1), “As-hatched broiler performance”. |