Table 4.
Performance and economic outcome variables, with descriptions and formulas
| Variable | Description |
|---|---|
| In-weight, kg | Individual full body weight taken at feedlot entry |
| Exit weight, kg | Carcass weight per dressing %, per lot basis |
| Dressing, % body weight, per lot basis | Carcass weight as a percentage of body weight1, used to calculate exit weight from carcass weight |
| ADG, kg/d | Average daily gain |
| ADG to first BRD pull, kg/d | Average daily gain to time of first BRD pull |
| Carcass weight, kg/carcass | AUS-MEAT hot standard carcass weight once the live animal has been slaughtered, with hide, feet, tail, head, and innards removed (Polkinghorne et al., 2008) |
| MSA (Meat Standards Australia) marble score | MSA marbling score (range 100–1,190)(Polkinghorne et al., 2008) |
| MSA index | Prediction of eating quality potential of a carcass based on carcass measurements (range 30–80)(McGilchrist et al., 2019) |
| P8 fat depth | Fat depth at the P8 site at crest of third sacral vertebra measured on the hot carcass |
| Rib fat depth | Subcutaneous depth of fat over the quartered rib site between the 5th and 13th ribs measured on the chilled and quartered carcass |
| Purchase price, $/animal | Cost to purchase each animal for feedlot entry. Calculated based on market prices at the time of purchase (range: AU$2.75 to $3.50 $/kg) |
| Feed cost, $/animal | Estimated cost of feed consumed for each animal on a DM basis based on $270/tonne |
| BRD treatment cost, $/animal | Individual drug cost for animals treated for BRD. Includes BRD vaccination cost at feedlot entry of $5.67/animal plus the cost of drug treatments |
| Other treatment cost, $/animal | Individual drug cost for treatments of ailments other than BRD. Ailments include lameness, acidosis, and polioencephalomalacia |
| Price received, $/kg carcass weight (cwt) | Price received at slaughter per kg of carcass weight. Price paid by abattoir according to pricing grid |
| Slaughter value, $/animal | Price received × carcass weight |
| Net return, $/animal | Slaughter value—purchase price—induction processing cost3—feed cost—BRD treatment cost—other veterinary treatment cost—yardage cost4—transport cost5—buyers commission—levy |
| Body removal cost6 | Average cost of body removal per animal. Estimated at AU$60/mortality according to time and labor units required |
1Lot dressing percentage calculated based on lot exit body weights by the feedlot, however only dressing % data were obtained for this study to calculate exit weight.
2Weight days = average weight of animal x total DOF. Pen weight days = ∑DOF of all animals in pen × ∑average weight of all animals in pen.
3Induction processing cost: $7.30/animal includes labor, ear tags, hormonal growth promotant implant, 5-in-1 clostridial vaccination, and antiparasitic injection.
4Yardage cost: Total DOF × yardage cost (approximately AUD$1.05/d/animal).
5Transport cost: flat load rate of AU$635/load with a load weight limit of 35,500 kg/load.
6Body removal cost calculated using an average time of 30 min per dead using two labor units at a labor rate of AUD$35/h plus fuel and machinery costs of $42.50/h.