Methods and Compositions for Genetically Detecting Improved Milk Production Traits in Cattle

A method for selectively breeding dairy cattle for improved milk production trait, the method comprising detecting single nucleotide polymorphism (SNP) in bovine proteinase inhibitor (PI) gene, wherein the PI gene has have a nucleic acid sequence of SEQ ID NO:

• 1, wherein the identity of at least a nucleotide at position 164, 269, 284, 407 or 989, and comparing the identity of a cell from a dairy cattle or an embryo of a dairy cattle is determined and compared to the nucleotide identity at a corresponding position of SEQ ID NO:
• 1, and wherein the dairy cattle or the embryo is selected if its PI gene has at least one of the following single nucleotide polymorphisms:
• nucleotide A at position 164, nucleotide T at position 269, nucleotide T at position 284, nucleotide C at position 407, and nucleotide T at position 989.

A method for selectively breeding dairy cattles, comprising selecting a bull that is homozygously haplotype 1 and using its semen for fertilizing a female animal.