Breeding Worth is the industry index which ranks cows and bulls on their ability to breed profitable and efficient replacement dairy heifers.
How economic values (EV's) are calculated and why they change.
EV’s represent the value of different traits to New Zealand dairy farmers.
The economic values are applied on a 'profit per unit' basis. For example, one additional kg of protein creates $4.26 of additional profit for a dairy farmer.
Calculations account for milk production, historical, current and forecast milk prices, income from culls, surplus cows and bobbies, the cost of generating replacements and general dairy farm expenses.
Economic values are updated every year to reflect changes in these values, ensuring Breeding Worth remains relevant in an ever-changing market environment.
Effective emphasis on the individual traits within Breeding Worth.
February 2020: Economic Value Update
The five-year average milk price ($/kg of milksolids) and the five-year average value component ratio (VCR; value of milk fat relative to milk protein) are key inputs to the economic value calculations.
In the 2020 update, both inputs increased. The average milk price increased from $5.92 to $6.32, while the average VCR increased from 1.01 to 1.16. This results in an increase in the value of milk fat, alongside a slight decrease in the value of milk protein.
The 2020 update to economic values led to an increase in BW for most animals. This BW lift reflects the increased profitability of dairy cows under a stronger milk price. The BW of cows and bulls that rank highly for milk fat production increased the most. Overall, re-ranking among animals and across breeds was minimal.
The table below shows the new economic values.
| Trait (units) | BW 2020 | BW 2019 | % change |
| Economic value ($/unit change) | |||
| Milkfat ($/kg) | 4.25 | 3.49 | +22% |
| Milk protein ($/kg) | 4.26 | 4.38 | -3% |
| Milk volume ($/L) | -0.094 | -0.092 | +2% |
| Live weight ($/kg) | -1.38 | -1.30 | +6% |
| Residual survival ($/day) | 0.105 | 0.112 | -6% |
| Somatic cell score ($/SCS) | -37.11 | -37.30 | -1% |
| Fertility ($/CR42) | 5.92 | 5.88 | +1% |
| Body Condition Score ($/unit) | 101.96 | 96.30 | +6% |
How this has impacted the BW of AE-enrolled bulls
On average Breeding Worth has increased. For bulls born after 2000 with a BW Reliability of 75% and a BW 2019 of >0, the average shift is around +$7.
Shift in Breeding Worth for AE enrolled sires.
Economic Values - factors and effects
Milk fat, milk protein and milk volume
These are calculated using a five-year rolling average of the milk solids, volume charge and value component ratio.
Liveweight
Liveweight differences in cows can affect their maintenance requirements, feed costs, value as a cull cow and the value of their calves.
Somatic Cell Count
Differences in somatic cell count (SCC) can have a significant economic effect.
Fertility
The economic value for fertility includes value gained through increased survival and value gained through earlier calving dates (i.e. longer lactations).
Residual survival
The economic value for residual survival recognises that animals with better longevity will reduce the requirement for replacement heifers.
Body Condition Score
The economic value for BCS represents the improved profitability of an animal that can maintain body condition over her lactation.
