Table 2 Baseline dairy cattle performance parameters

Annual milk yield (kg FPCM)^a,b

4500

Age at first calving (mo)^c

26.0

Calving interval (mo)^c

14.0

Live calves born per cow per year^d

0.81

Calves destined as heifer replacements^e

0.29

Calves destined as beef cattle^f

0.50

Proportion of lactating cows in the population^c

0.45

Proportion of dry cows in the population^c

0.06

Proportion of replacement heifers in the population^c

0.48

Proportion of bulls in the population^c

0.01

Proportion of replacement heifers born that enter herd^c

0.85

Replacement rate (%)^c

25.0

Calf and growing cattle mortality (%)^c

5.0

Milk lost per cow death (kg FPCM)^b,g

8357

Milk lost per non-yielding day of lactation (kg FPCM)^b,h

14.4

GHGe per kg FPCM (kg CO₂eq)ⁱ

1.50

Annual GHGe per dairy cow in the herd (kg CO₂eq)^,j,k

6750

Proportion of GHGe attributed to herd maintenance^c

0.58

Proportion of GHGe attributed to lactation^c

0.42