Source: Alberta Beef Producers
Wide variation between individual animals.
Changes in diet, environment and other factors will trigger different genetic responses in individual cattle, which may result in some animals that are more feed efficient than others, says Dr. Gordon Murdoch, a research associate in animal physiology.
Changes in gene expression in relation to whole animal metabolism, were among measurements noted in the project that looked for the genetic signposts that identify animals with superior energetics and feed efficiency.
Energetic efficiency refers to an animal’s ability to use energy for both maintenance requirements and growth. An animal with better energetic efficiency will grow more under the same conditions and nutrient provision than an animal with poorer energetic efficiency.
“The research lays the foundation for developing a process to select animals with the genetic ability to be much more feed efficient,” says Murdoch. “If producers can select cattle with essentially equal optimized feed efficiency, it means instead of putting 100 head on pasture, they could perhaps graze 115 head that will all gain at the same rate, but with no additional input costs.”
There would be more cattle on the same amount of grass, all achieving the same gains. The research showed there are “greater individual variations among cattle in a herd than we previously thought,” says Murdoch. There may be some genetic differences between breeds, but the greater variation in this study was between individual animals. Again, using 100 head of cross-bred steers on pasture as an example, he found there may be 10 head in that herd may consume 125% as much grass as the other animals, yet gain the same amount of weight. Those 10 are inefficient, he says.
The practical application is to develop a process to select young cattle or breeding stock with the superior energy and feed efficiency without selecting against other beneficial livestock attributes.