Beef: Heat measurement - a key to feed efficiency in cattle

Wednesday, November 4, 2009

Infrared technology may be able to help detect which animals are giving off more heat in the rumen, an indicator of poor feed efficiency

by DON STONEMAN

A link has been established between feed efficiency and the heat emitted by cattle after they eat, says University of Guelph animal scientist and geneticist Steve Miller.

Cattle that produce more heat – and methane – require more feed to get to market finish.

Now a study by University of Guelph animal science graduate student Yuri Montanholi shows a correlation between feed efficiency and the heat that is dissipated from cattle's cheeks and feet after they eat.

Montanholi measured the heat with infrared thermography, a technology used by firefighters to detect hot spots in a building. The temperature measuring gun costs about $50,000.

He also measured the difference in heat emanating from the right side of an animal, which represents core body temperature, and the left side, which represents rumen temperature. More heat produced in the rumen indicates poorer feed efficiency and more methane, an undesirable greenhouse gas.

Miller is working with Agriculture and Agri-Food scientist Al Schaefer at the Lacombe Research Centre in Alberta. Schaefer placed an infrared camera at the water bowl to record temperatures of possibly sick animals. Miller thinks this could be used to predict which bulls are more feed-efficient. This would be a pre-test before they undergo genetic testing for desirable traits.

The ultimate tool here is genomics, Miller's specialty. He notes that the DNA code of the cell of a beef animal is known to contain two million different combinations, called Single Nucleotide polymorphisms (SNPs). There may be 100 SNPs responsible for a single desirable trait such as marbling, he says. Tenderization tests are available now, he adds.

The research station at Elora has measured 700 animals for feed efficiency. Geneticists are putting together the relationship between different SNPs and feed efficiency. Miller says Guelph has been working with Beef Co-operative Research Centres in Australia and the U.S. Department of Agriculture to combine datasets to create the best test possible for predicting feed efficiency. Miller adds that 20-40 per cent of the differences seen in cattle are due to genetics rather than environment.

Genomic studies likely represent the way to go, according to Beef Improvement Ontario (BIO) general manager Mike McMorris.

Feed intake on the animals is already captured at the Elora research station using units costing $100,000, McMorris says. BIO recently applied for a grant from Agriculture and Agri-Food Canada's Agriflex program to do that at all of its bull test centres.

BIO is also looking for money to offset the producer's cost of $60 a head to evaluate bulls, using a system developed by Merial. Breeders are analyzing bulls now for a number of traits. "We want to shorten the adoption curve" for the new technology, McMorris says.

Farmers could take advantage of this technology in as little as two years, McMorris says. The Merial genomics test involves removing a small piece of skin while placing an ID tag in the animal's ear. The skin is then tested and the DNA examined for different traits. Pfizer offers a competing product, McMorris says. BF