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 (EVs) 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 $6 of additional profit for a dairy farmer.
Calculations account for milk production, historical, current and forecast milk prices, income from culls, surplus cows and bobbies, the cost of generating replacements and general dairy farm expenses.
Economic values are updated every year to reflect changes in these values, ensuring Breeding Worth remains relevant in an ever changing market environment.
February 2019: Economic Value Update
In February 2019, the Economic Values used to calculate Breeding Worth will be updated. This update reflects changes on the world market where there has been a significant increase in the value of fat and a decrease in the value of protein. The good news is that the high value of milk fat is delivering a strong milk price for the 2018/19 season.
Effective emphasis on the individual traits within Breeding Worth.
The table below shows the new economic values.
| Trait | 2018 | 2019 | Change |
| Milkfat ($/kg) | 2.85 | 3.45 | 0.60 |
| Milk protein ($/kg) | 6.06 | 4.34 | -1.72 |
| Milk volume ($/L) | -0.088 | -0.092 | 0.004 |
| Live weight ($/kg) | -1.30 | -1.30 | 0.00 |
| Residual survival ($/day) | 0.124 | 0.111 | -0.013 |
| Somatic cell score ($/SCS) | -38.33 | -37.2 | 1.1 |
| Fertility ($/CR42) | 6.55 | 5.84 | -0.71 |
| Body Condition Score (Units) | 100.6 | 95.7 | -4.9 |
Key assumptions
Economic values are calculated assuming industry averages for animal production, feed requirements and farm systems. The following table is a list of the key averages which are incorporated into the Economic value calculations.
How this will impact the BW of AE-enrolled bulls
The BW of high fat sires will increase, and conversely the BW of high protein sires will decrease. For bulls born after 1999 with a BW Reliability of 75% and a BW 2018 of >0, Friesian bulls are the most affected, with an average shift of -$27.7. Jersey, Cross-Bred and Ayrshire bulls have shifts of $23.3, -$4.8 and -$3.4 (see graph).
Shift in Breeding Worth for AE enrolled sires.
Economic Values explained
Protein, Milk Fat, Milk Volume
The EVs for milk components are calculated using a 5 year rolling average, which accounts for the past four years of pricing, as well as price forecasts for one future season.
Liveweight
The EV for liveweight comprises four components: cow maintenance requirements, heifer replacement feed costs, cull cow value and bobby calf value.
Somatic Cell Score
A decrease in somatic cell score can have a significant economic effect. The following effects are accounted for in the calculation of the SCS economic value.
Fertility
The EV for fertility includes value gained through increased survival and value gained through earlier calving dates: longer lactations.
Residual Survival
The EV for residual survival is based on the rationale that animals with better longevity will reduce the requirement for replacement heifers entering the herd.
Body Condition Score
The EV for Body Condition Score (BCS) represents the improved profitability of an animal who is able to maintain body condition over her lactation.
