Researchers with Scotland's Rural College (SRUC) has determined that the telomeres — which protect the end of chromosomes — of cows deteriorate most in the weeks and months after birth, indicating how long an animal may live and how healthy it may be.
The research also looked at how factors such as illness and stress can affect a telomere, and the results can help inform human geneticists looking at human life expectancy.
SRUC professor Mike Coffey and his team studied the lives of 700 cows from the Langhill herd of cows housed at Crichton Royal Farm in Dumfries, Scotland, taking more than 2,000 blood samples.
“The data we have collected is the biggest in the world on repeat measure of telomere length on the same animal over time, so it is very valuable. We can inform the human geneticists,” Coffey said.
According to SRUC, the study of telomere deterioration is helping scientists prolong life. Telomeres reduce every time a cell divides because the repair mechanism that puts the DNA strands back together is not 100% effective, meaning a little bit is lost each time.
Professor Melissa Bateson from the Institute of Neuroscience at Newcastle University added, “I think the animal work is really important for helping us make sense of what is going on.”
She said the animal research is important because it can also include experiments, unlike human research into telomeres.
“If you show that stress is causal in shortening telomeres in animals, it gives more credence to the idea that something similar may be going on in humans," Bateson said.
“There is a certain amount of evidence to show that humans and animals that have shorter telomeres have shorter healthy life expectancy. It is telling you something over and above your chronological age," she added. “If we think that telomeres are a measure of biological age, ... it can contribute to our understanding of what kind of lifestyle factors are going to make you live a long, healthy life and which ones might be going to make you die young.”
Coffey said he will use the research to find ways of producing better dairy and beef cattle.
“We found that most of the loss of telomere length takes place early in the animal’s life. Cells divide rapidly early in life, so the argument is that animals who are born with longer telomeres have a greater chance of survival before the shorter telomeres limit their lives,” Coffey said.
The easy-to-obtain biological marker can be used for selection in animals — i.e., longer telomeres mean the animals live longer and, thus, would be better for dairy or breeding, while those with shorter telomeres would be better used for fattening up for beef. Tests can also look at the lengths of telomeres in the offspring of specific bulls to decide which ones are best for breeding.
“That would provide information for a farmer to make an appropriate decision early on in the animal’s life,” Coffey said.
"The Genetic Architecture of Bovine Telomere Length in Early Life & Association with Animal Fitness” appeared in Frontiers in Genetics.