Development through DNA

Isaac Haagen

While effective management plays a role in increasing production, so do genetics. In a recent webinar, Iowa State University Extension examined dairy goat genetics and their role in milk production.

“The goal of a breeding program, generally speaking, is to improve herd profitability,” said Isaac Haagen, an assistant professor and extension specialist of dairy production at the University of Minnesota.”

Improving milk yield can go a long way in improving profitability.

“There are a lot of management and environmental factors that go into what shapes how much milk a doe produces,” Haagen said. “In general, if we’re talking about yield traits, 20% of the variation in the amount of milk that a doe produces is attributed to genetics and 80% is attributed to management and environment.”

Haagen’s presentation was supported by the 2026 Sustainable Dairy Goat Agrisystems project, which was awarded to Iowa State University in 2024. SDGA is a program that supports regenerative and profitable U.S. dairy goat production systems through research, extension and farm-level assessments.

To improve production through genetics, Haagen said producers should ask four questions: What are the goals of the breeding program; what are the traits evaluated; what is the selection index; and what are the key tips for creating a breeding program.

“Most of the time the primary goal for improving genetics is to improve herd profitability in the production sphere,” Haagen said. “That’s where our primary revenue source is, selling milk off the farm. First, you need to think about the phenotype, which is more broadly just our trait of interest.”

Haagen went on to discuss the importance of selecting traits for a specific goat herd, educating on Predicted Transmitting Ability, and Estimated Transmitting Ability.

“These represent the genetic performance that a parent is expected to pass on to their offspring,” Haagen said. “The key difference between these two values is that a PTA includes an animal’s own performance or the performance of the offspring.  If a doe has participated in milk recording, she has performance records from herself that are contributing to the PTA value.”

The goal for using these values is to help combine economically relevant traits into a single value that producers can use for selection. Rarely is it recommended to breed based on a single trait.

“There are a lot of traits that can contribute to the economic value of an animal or the profitability of an animal,” Haagen said. “It’s not simply does the animal make more milk than another, and we really want to combine all economically relevant traits into a single value.”

Haagen discussed in detail the milk fat protein index, published by the Council on Dairy Cattle Breeding. This index combines milk fat and protein values to put an economic weight on each PTA unit. The American Dairy Goat Association publishes its own separate index that also includes type traits, called the Production Type Index.

One index weights production two times the value of type, and the PTI values type at two times the weight of production.

Genetic evaluations begin with milk samples collected on the farm through Dairy Herd Improvement, which weighs daily milk production and sends a milk sample to a lab to test components like butterfat and protein. The dairy records processing center standardizes that information to be sent to the CDCB. The ADGA provides the CDCB with linear type evaluations and pedigree information and the CDCB calculates the PTAs, which flow back into the goat industry to use for genetic selection.

“Selection primarily happens on the male side,” Haagen said. “Especially if utilizing artificial insemination. If using A.I., it allows you to gain superior genetics from another herd and bring them into your own. A male is able to produce more offspring than a female, therefore, our selection primarily occurs on the male side. Secondly, it’s important to select bucks on an index.”

Those indexes include the milk fat protein index or PTI. The “best” index depends on the goals of each dairy.

“There are a lot of advantages to using artificial insemination in your goat herds,” Haagen said. “First and foremost is the genetic improvement piece of it. By utilizing A.I., we can access reliable superior genetics from other herds. Because we select superior genetics of animals of higher merit, we have an increased rate of genetic gain, so we can make faster genetic progress, and it allows us to reduce the relatedness of our herd.”