NZAEL to deliver improved Breeding Values
By upgrading its genetic evaluation systems in a two-stage process, NZAEL is to deliver improved breeding values to New Zealand dairy farmers. The first stage takes place this year, the second in 2021.
There are currently eight traits that have been identified as having a measurable economic value to NZ farmers, and these breeding values are combined with the relevant economic values to produce Breeding Worth (BW).
Breeding Worth is the industry index which ranks cows and bulls on their ability to breed profitable and efficient replacement dairy heifers.
Breeding Values Explained
Breeding values are calculated using information which is collected by farmers, on-farm. For example:
- Herd Testing data
- Weighing data
- Body Condition Scores (when collected for each individual cow)
- ‘Traits other than production’ scores
Cows which are routinely measured will have more accurate breeding values.
When a heifer calf is born, her initial breeding values will be calculated as an average of her parents. This means that is it crucially important that the mother of a calf is identified correctly at birth.
The accuracy of a bull’s breeding values increase as more of his daughters are measured.
Production Efficiency
Protein


- Protein is a moderately heritable (31%) trait. You should aim to increase protein breeding value over time. Genetic gain has been around +1.1 kg/year, irrespective of breed.
Fat


- Milkfat is a moderately heritable (33%) trait. You should aim to increase milkfat breeding value over time. Genetic gain has been around +1.0 kg/year, irrespective of breed.
Milk volume


- Milk is a moderately heritable (36%) trait. Genetic gain has been pretty consistent at around +19 litres/year with greatest rates of genetic gain in Friesians.
Liveweight


- Liveweight is a moderately heritable (35%) trait. You should aim to maintain liveweight breeding value over time. Liveweight breeding values are slowly increasing over time.
Robustness
Somatic cell score


- Somatic cell score has a heritable of 15%. You should aim to lower somatic cell score breeding value over time. (Negative is best). Somatic cell score breeding values have been slowly decreasing since 2004, when the trait was introduced into BW.
Fertility


- Fertility is a low heritability (9%) trait. You should aim to increase fertility breeding value over time. Genetic losses were observed from 1990 to 2000, but genetic gains have been made since 2002 when the fertility breeding value was first included in BW.
Residual survival/Total Longevity


- Residual survival is a low heritability (6%) trait which is derived from the Total Longevity breeding value. You should aim to increase Residual Survival over time.
Body condition score


- Body Condition Score is a moderately heritable (~25%) trait; you should aim to increase body condition score over time.
The Animal Evaluation system is able to produce breeding values for a total to 27 different traits. In addition to the traits included in Breeding Worth, farmers are able to access Breeding Values for a full range of TOP traits (Conformation and Udder traits) as well as gestation length, calving difficulty and lactation persistency.
Farmer Opinion Traits
Farmers with progeny test herds assess heifers for ‘opinion’ traits. This data feeds into their breeding values, as well as those of their sire and dam.
Click the arrows on the slider below to learn what each score represents, and how you can use them to breed improved temperament in your herd.
Body and Dairy Conformation Traits
Cows can be assessed by certified TOP inspectors for a range of body conformation traits. This data feeds into their breeding values, as well as those of their sire and dam.
Click the arrows to learn what each score represents, and how you can use them to breed improved conformation in your herd.
Udder Conformation Traits
Cows can be assessed by certified TOP inspectors for a range of udder conformation traits. This data feeds into their breeding values, as well as those of their sire and dam.
Click the arrows to learn what each score represents, and how you can use them to breed improved udders in your herd.