Table 1.
Inputs used to calculate the cost of 1 case of subclinical ketosis (SCK; defined as elevated serum BHBA ≥ 1400 μmol/L in either of the first 2 weeks following calving in a cow not showing clinical signs)
| Item | Value | Reference |
|---|---|---|
| Price/cost | ||
| Average milk price in Canada ($/L) | 0.81 | (22) |
| Cost ($) of 1 kg of TMR (dry matter basis) to produce 1 L of milk | 0.3 | (20) |
| Average value of a cow in a herd ($) | 2100 | (20) |
| Cost of pregnant replacement heifer ($)a | 2500 | (23) |
| Cull cow value ($)b | 1680 | (23) |
| Cost of 1 day open beyond 100 days ($) | 3 | (21) |
| Herd/cow data | ||
| Herd annual turnover rate (%) | 35 | |
| Median time to pregnancy (d) in cows without SCK | 108 | (7) |
| Median time to pregnancy (d) in cows with SCK in 1st or 2nd wk postpartum | 124 | (7) |
| Median time to pregnancy (d) in cows with SCK in 1st and 2nd wk postpartum | 130 | (7) |
| Dairy efficiencyc | 2.3 | |
| Milk reduction (kg) for 30 days due to SCK | 65 | (4,5) |
a
Pregnant replacement heifer price is based on average weight of 454 kg and $250/cwt.
b
Cull cow value is based on average weight of 635 kg and $120/cwt.
c
Milk yield (kg) produced as a result of a cow consuming 1 additional kg of dry matter above maintenance requirements (24); this calculation accounts only for the concentration energy required to produce marginal milk after considering that NEL of 0.75 Mcal/kg of 4% milk and 1.73 Mcal/kg of feed on a dry matter basis (25).