As spring nears, a young student’s thoughts turn to classic rites of passage: spring break; convocation; projects on retained heterozygosity. Though that last one may not be for everybody, it was front and centre for 30 third-year veterinary medicine students at the University of Calgary.
“Every year, our third-year class does an original research project,”said Dr. Alastair Cribb, Professor, Clinical Pharmacology, Department of Comparative Biology and Experimental Medicine at the University of Calgary. “This class was interested in Dr. John Basarab’s work with Genome Alberta on genomics to improve carcass quality and feed efficiency in beef cattle.”
The value of vigour
Specifically, they looked at his findings regarding hybrid vigour or retained heterozygosity— the improved function of any biological quality in a hybrid offspring— and reproductive efficiency that led to the development of EnVigour HX™. This genomic tool combines parentage verification, genomic breed composition and a genomic-retained heterozygosity score (Vigour Score) to provide tools for producers to improve cattle production efficiency.
“We know the relationship between genomic-retained heterozygosity—a marker of hybrid vigour—and reproductive efficiency of the dam, but we don’t know the association with calf health,” said Cribb.
After finding a producer willing to work with them, and securing additional funding from the Faculty of Veterinary Medicine, the Class of 2020 partnered with Basarab to genotype all 552 calves born in one year, tracking them through weaning to 60 days post-weaning; bulls were also genotyped. The question was whether an association could be found between the hybrid vigour of the calf and its health, and the initial answers are encouraging.
“Preliminary analysis of the data suggests there is a connection between the hybrid vigour score and health. Resistance to specific diseases was not investigated, but higher-retained heterozygosity was associated with a decrease in deaths and sick calves up to weaning.”
Knowing the genomic breed composition of the dams and the bulls gives the producer more guidance on which bulls to select for breeding.
“You want calves that have strong hybrid vigour. If you pick the wrong bull to breed with, you’ll produce calves with low vigour scores. The work that we’re doing and the research by Dr. Basarab is about using genomic information to be smarter in your breeding program. In the process, you can reduce the rate of disease and mortality.”
Knowing the score
Though they aren’t yet able to release exact numbers, Cribb’s students found that above a particular hybrid vigour score, the health impact on calves was significant.
“John’s project has been focusing on reproductive efficiency and fertility. John is continuing his work on effects on productivity, and we have added a health component to the mix. The results with these 550 calves are a good start and suggest we should continue to pursue this with more animals to confirm the preliminary findings. Healthier animals are important for productivity, and can help ensure a healthy bottom line for producers.”
That progress was only possible thanks to the collaboration between the University of Calgary and Genome Alberta.
“John and his team brought their expertise in genomics, the data they had collected thus far and substantial funding. We contributed time, effort, data and some additional funding, and together we made it happen.”
The results also suggest there may be more economic value in genotyping your dams and bulls than previously thought, which is more good news for producers.
As it turns out, the benefits from this project aren’t restricted to the animals.
“This is a good example of training the next generation of veterinarians to better understand genomics and how it can be applied in the cattle industry to maximize productivity and health.”