DNA strands intertwining with a cow silhouette, symbolizing dairy genetics.

Decoding Dairy: How Genetics Can Improve Your Milk

Rhea Morgan in Science & Nature August 2025 • 4 min read.

"Unlocking the secrets of Turkish cattle breeds through genetic analysis to enhance milk production and quality."

For centuries, dairy farming has been a cornerstone of agriculture, with milk serving as a vital source of nutrition. But what if we could enhance milk production and quality through a deeper understanding of cattle genetics? Recent research is doing just that, exploring how specific genes influence milk yield and composition, paving the way for more efficient and sustainable dairy practices.

At the heart of this genetic exploration are genes like growth hormone (GH), prolactin (PRL), and diacylglycerol acyltransferase (DGAT1). These genes play crucial roles in various biological processes, and variations within them (known as polymorphisms) can significantly impact milk production traits. By identifying and understanding these genetic variations, breeders can make informed decisions to improve their herds.

This article delves into a study focusing on the genetic diversity of four native Turkish cattle breeds, examining the polymorphisms in the GH, PRL, and DGAT1 genes. We'll explore how this research contributes to our understanding of cattle genetics, potentially leading to advancements in dairy farming practices not only in Turkey but around the world.

The Genetic Blueprint: Understanding GH, PRL, and DGAT1

DNA strands intertwining with a cow silhouette, symbolizing dairy genetics.

The study employed a technique called PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) to analyze specific DNA fragments of the GH, PRL, and DGAT1 genes. This method allows researchers to identify different versions (alleles) of these genes within the cattle population. Specific enzymes are used to cut the DNA at specific points, revealing different band patterns that correspond to different genetic variations.

Here's a breakdown of the key genes analyzed and their significance:

Growth Hormone (GH): Located on chromosome 19, GH influences growth and metabolism. Specific variations in the GH gene have been linked to milk and meat yield. The study looked at two variations (GH-MspI and GH-AluI).
Prolactin (PRL): Found on chromosome 23, PRL is vital for milk production. Variations in the PRL gene are known to affect milk yield, fat content, and protein content. The study investigated the PRL-RsaI variation.
Diacylglycerol Acyltransferase (DGAT1): Situated on chromosome 14, DGAT1 is related to milk fat content. A specific variation (K232A) in the DGAT1 gene has a major effect on milk composition, where one variant (K) is associated with high fat content, and another (A) with higher milk yield.

By analyzing the presence and frequency of these different alleles within the four Turkish cattle breeds, the researchers aimed to assess the genetic diversity and potential for improving milk production traits.

Implications for the Future of Dairy Farming

This research provides valuable insights into the genetic makeup of Turkish cattle breeds, adding to the global understanding of cattle genetics. By identifying the allele frequencies of key genes related to milk production, breeders can make more informed decisions when selecting animals for breeding programs.

For example, if the goal is to increase milk fat content, breeders might select for animals with a higher frequency of the GH-MspI (-) and GH-AluI (V) alleles, which have been linked to higher fat content in previous studies. Conversely, to increase milk yield, selecting for the GH-MspI (+) and PRL (A) alleles could be beneficial.

While this study focused on Turkish cattle breeds, the principles and methods used can be applied to other breeds around the world. Understanding the genetic factors that influence milk production is crucial for developing sustainable and efficient dairy farming practices that meet the growing global demand for milk and dairy products.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.3906/zoo-1409-9, Alternate LINK

Title: Growth Hormone (Gh), Prolactin (Prl), And Diacylglycerol Acyltransferase (Dgat1) Gene Polymorphisms In Turkish Native Cattle Breeds

Subject: Animal Science and Zoology

Journal: TURKISH JOURNAL OF ZOOLOGY

Publisher: The Scientific and Technological Research Council of Turkey (TUBITAK-ULAKBIM) - DIGITAL COMMONS JOURNALS

Authors: Emel Özkan Ünal, Eda Şeyma Kepenek, Havva Di̇nç, Füsun Özer, Gizem Sönmez, İnci Zehra Toğan, Mehmet İhsan Soysal

Published: 2015-01-01

Everything You Need To Know

How do variations in the growth hormone (GH) gene affect milk production in cattle?

Variations in the growth hormone (GH) gene, located on chromosome 19, are associated with both milk and meat yield. The study specifically examined GH-MspI and GH-AluI variations. These variations impact growth and metabolism, ultimately affecting how much milk a cow produces and its meat quality. Understanding these specific genetic markers allows for targeted breeding programs to enhance these desirable traits.

What role does the prolactin (PRL) gene play in milk production, and what specific traits are influenced by its variations?

Prolactin (PRL) is essential for milk production, and variations in the PRL gene, found on chromosome 23, are known to influence milk yield, fat content, and protein content. The study focused on the PRL-RsaI variation. While the study highlights the importance of PRL-RsaI, other PRL variations could also play a role in milk production characteristics, and further research may uncover additional insights. Understanding PRL gene variations provides a powerful tool for dairy farmers to improve milk quality and quantity.

How does the diacylglycerol acyltransferase 1 (DGAT1) gene impact milk composition, and what are the implications of the K232A variation?

The diacylglycerol acyltransferase 1 (DGAT1) gene, located on chromosome 14, significantly affects milk fat content. The K232A variation in the DGAT1 gene is particularly important; the K variant is linked to higher fat content, while the A variant is associated with increased milk yield. This means breeders can strategically select for specific DGAT1 variants to achieve desired milk compositions. However, DGAT1 is not the only gene affecting milk fat, other genes and environmental factors also play a role. Understanding and manipulating the DGAT1 gene is a key strategy to improving milk quality and production.

What is PCR-RFLP, and how was it used to analyze the GH, PRL, and DGAT1 genes in Turkish cattle breeds?

PCR-RFLP, or Polymerase Chain Reaction-Restriction Fragment Length Polymorphism, is a technique used to analyze specific DNA fragments of genes such as GH, PRL, and DGAT1. This method allows researchers to identify different versions (alleles) of these genes within a cattle population by using specific enzymes to cut the DNA at specific points, revealing different band patterns that correspond to different genetic variations. This technique allows for precise identification of genetic differences without sequencing the entire genome, making it a cost-effective tool for genetic analysis.

How can understanding the genetic diversity of Turkish cattle breeds lead to improvements in dairy farming practices?

By understanding the genetic diversity within Turkish cattle breeds, breeders can make informed decisions about which animals to breed. For instance, if the goal is to increase milk fat content, they might select animals with the K variant of the DGAT1 gene. If the goal is to increase milk yield, they might select animals with the A variant. This targeted approach can lead to more efficient and sustainable dairy farming practices, improving both the quality and quantity of milk produced. Furthermore, understanding the genetic diversity in these breeds also allows for conservation efforts and preservation of genetic heritage.