Methods and consequences of including reduction in greenhouse gas emission in beef cattle multiple-trait selection

Table 1 Key characteristics for the example self-replacing beef cattle production system producing 100-d feedlot finished steers

Characteristic	Value
Calendar
Month of joining	Oct
Start month of limited feed period^a	Jan
End month of limited feed period	Sept
Carbon price
Price of carbon, $/ton CO₂-e	20
Young animals
Age at weaning, m	7
Growth rate at pasture in limited feed period (relative to surplus feed period), − 1.0 to 1.0	0.7
Cost of extra feed at pasture, $/ton	130
Quality of extra feed at pasture, MJ/kgDM	8
Period of feedlot finishing, d	100
Steer live weight at feedlot entry, kg	450
Cost of extra feedlot feed, $/ton	270
Quality of extra feedlot feed, MJ/kgDM	10
Age at finished sale, m	22
Steer live weight at finished sale, kg	640
Finished steer sale price, cents/kg carcass	456
Cows (averages)
Weaning %	85
Weight loss from calving to joining, kg	50
Live weight at joining, kg	650
Mean condition score at joining^b	3−
Min. acceptable condition score at joining^b	2+
Max. acceptable condition score at joining^b	4+
Cost of extra cow feed, $/ton	130
Quality of extra cow feed, MJ/kgDM	8
Live weight of surplus cows, kg	550
Sale price for surplus cows, $	990

From the example used by Barwick et al. [9], with carbon priced at $20/ton CO₂ equivalent
^aAll of the year except when surplus feed is available
^bScored on a 15-point scale from 1 − (emaciated) to 5 + (obese)

ISSN: 1297-9686