The major cost in producing cattle is feed.  The high demand and price for corn and other commodities is raising finishing costs and devaluing feeder cattle.  It’s also impacting land use decisions which puts inflationary pressure on pasture and forage costs.  The situation has brought about considerable interest in improving the efficiency of cattle consuming expensive feed inputs.

Feed storage, processing, additives and delivery that minimize waste and maximize utilization are critical.  Likewise, large economic impacts might be possible through genetic improvements associated with raising cattle more metabolically efficient in their use of feed.  Research has identified there are heritable differences in cattle for feed efficiency.  The amount of variation and potential savings is large, stimulating study and technology regarding how to measure and improve.

Feedyards have routinely tracked pen feed conversion (lbs of feed consumed per lb of gain) as a key economic benchmark.   It has never been widely pushed as a genetic trait for several reasons.  It is difficult to measure actual feed consumption for individual animals and good conversions are favored by high feed intake in which maintenance energy needs are diluted over high average daily gains.  Better feedlot conversion ratios are associated with higher growth rate, larger size cattle.

Some advancing technologies for measuring individual animal feed intake and for expressing feed efficiency are moving the industry toward being able to select cattle that eat less while gaining the same.   Feed bunks with load cell scales which continually weigh a feed tub that is accessed by one animal at a time with a reader to identify the animal by radio frequency ear tag and computerize the data accumulation, track what an individual animal eats while in the pen on the feeding trial.   Using the feed intake information to calculate a residual feed intake (RFI) (defined as the difference between what an animal actually consumed and what was expected based on its growth and maintenance) identifies metabolic efficiency differences between individual’s independent of average daily gain and body size.

Testing groups of yearling bulls identifies individuals with a negative RFI (consumed less than expected for performance achieved) as well as positive RFI bulls (more feed).  This information can be utilized in the selection of bulls expected to sire calves with lower finishing feed costs and daughters with lower feed maintenance requirements. For yearling bulls on feed test the variation seen is over 5 lbs less feed per day for similar performance.   Selection for low RFI is anticipated to reduce cow herd maintenance requirements by up to 10% over time. It is further estimated selection for low RFI would lower methane emissions and reduce nutrients in manure.

A number of bull testing and marketing centers have invested in the equipment to be able to measure RFI and evaluate bulls for feed efficiency, including a couple of the largest test centers in both the US and Canada.  Additionally, several large seedstock breeders are measuring RFI on some of their best breeding prospects, and more and more land grant universities are becoming set up to measure individual efficiency in larger groups which will contribute to more meaning research.

Accompanying the measurement of individual feed intakes and the identification of  animals of  superior feed efficiency, has been the discovery of several genetic markers related to an animal’s ability to convert feed.  Due to the cost and complexity in measuring actual feed intake and calculating RFI, DNA profiling would be a much simpler means to evaluate a larger number of animal’s for their genetic ability to use feed more efficiently.  Present markers identify a portion of the variation we see for RFI, with the most favorably rated genotypes saving about 2.5lbs of feed per day at similar gains than the least favorable genotypes.  For many breed populations the practical range of variation identified by present markers is more likely to be .5 to 1 lb.

The economic potential from widespread improvement in feed efficiency is huge for the cattle industry.   At today’s high grain and feed prices, the measurement, evaluation and application of improving feed efficiency is rightly receiving a lot of industry and academic attention.