The Milk Producer - May 2011 - (Page 32)

RESEARCH By Natalie Osborne Predicting production Examining your cow’s liver gene expression could help determine her future lactation performance hat can your heifer’s liver amine gene expression, the process by how feed withdrawal altered that exreveal about her lactation which information contained in gene pression. potential? University of DNA is turned into proteins. MicroMicroarray data, as well as firstGuelph researchers want to deterarray technology is a new molecular lactation performance data collected mine a cow’s future lactation perfortool that provides simultaneous analfrom 81 of the original heifers, was mance just by examining her liver’s ysis of thousands of genes in a tissue used for the second part of the study. gene expression. Their goal is to find from an organism. “We compared the heifers’ gene exout how a gene in a cow’s liver afCopied from a segment of the pression data to their DHI traits and fects her physiology and production original DNA sequence, messenger wrote a model that uses gene exefficiency. ribonucleic acid, or mRNA, is a tranpression to predict lactation perforCurrent genetic selection techscript the cell uses as instructions mance,” says Doelman. “Protein and niques can detect gene variants called for building the protein encoded by fat percentage were some of the traits single nucleotide polymorphisms that the gene. The researchers examined most accurately predicted by our correspond to different production mRNA strands to identify which model.” traits. Animal and poultry science genes were expressed normally and Cant and Doelman’s early work professor John Cant and PhD suggests liver gene exprescandidate John Doelman are sion is a viable and accurate the first to study the dynamprediction method for future ics of liver gene expression, production. They plan to imas well as its ability to predict prove its accuracy by evaluatlactation success in post-puing different analytical modbertal heifers. els that could identify the best “A molecular biology appredictive genes. proach to evaluate gene prodAnalysing the predictive ucts could improve predictive power of gene expression accuracy and be used in comin white blood cells is also a bination with current genetic possibility. Producers could tests,” says Doelman. “We one day send a cow’s blood chose the liver because of its sample to a lab for analysis role in nutrient absorption to determine her production and distribution, and because potential. lactation is really a continuation of that process. It’s an ideal candidate for this type Natalie Osborne is a student writer with the University of of work.” Guelph’s office of research. The Cant and Doelman wanted project’s overall lead investigator to determine the feeding and is Dr. Anne-Marie de Passillé, fasting effect on liver gene exAgriculture and Agri-Food Canpression. They assigned 102 ada. Other collaborators include yearling Holstein heifers to a professors David Kelton and 24-hour total feed withdrawStephen LeBlanc, population al or a feed treatment, and medicine, and Trevor DeVries, collected blood samples and animal and poultry science. liver biopsies. The researchers used mi- Researchers want to find out how a gene in a cow’s Funding is provided by Dairy croarray technology to ex- liver affects her physiology and production efficiency. Farmers of Canada. 32 | May 2011 | MilkPRODUCER W

Table of Contents for the Digital Edition of The Milk Producer - May 2011

The Milk Producer - May 2011
Contents
Editor's Notes
DFO Chair's Message
Provincial Perspectives
Dairy Update
Farm Finance
DFC Promotion
Research
Ruminations
Applied Science
Markets
New 'N' Noted
Back Forty

The Milk Producer - May 2011