Animal Breeding Basics
Basics of Inheritance
Cattle, like people, inherit half of their genetic makeup from the sire and half from the dam. The genetics are inherited through chromosomes. Cattle have 30 pairs of chromosomes - meaning 60 total chromosomes. Each chromosome is made up of DNA in a long strand that is compacted tightly into the nucleus of each cell. Certain sections of the DNA called “genes” are transcribed into proteins that control nearly every function in life.
Every sperm and egg cell contains a unique set of chromosomes that are combined during fertilization to make a full set with two copies of each chromosome (except for the sex chromosomes) in the newly fertilized egg. Because each sperm and egg cell randomly end up with half of the available genetic material (chromosomes), every sperm and egg cell is unique and every resulting embryo contains a unique combination of genes inherited from its parents. This explains why full siblings can be so different from each other.
The history of breeding cattle in the United States is very dynamic. Breeders have gone through many stages and changes, each built from previous techniques and knowledge. Although past stages focused heavily on popular folklore, today’s focus is built on a foundation of sound science for producer profitability and sustainability.
Video on the History of Cattle Breeding by beefreproduction.org.