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RESEARCH ON THE RECORD – for Feb. 9, 2009

Barley Had As Much Net Energy Value As Corn

Barley is commonly fed in finishing diets in Canada and throughout the Pacific Northwest. However, corn accounts for 80 per cent of the energy grains fed to cattle in the U. S., and it is widely believed that corn has superior feeding value compared to barley. The objective of this Montana State Univ. study was to evaluate the performance, nutrient digestibility, and grain energy content of finishing diets based on corn or barley.

Corn-fed cattle had higher digestible intake of all nutrients which appeared to be partitioned toward external fat deposition, contributing to slightly higher avg. daily gain, gain/ feed, hot carcass wt., % KPH, 12th rib thickness, and numerical yield grade. Barley-fed cattle had higher total tract starch digestibility, and percentage of retail cuts. However, there was no difference in loin muscle area, marbling, USDA quality grade, or carcass value between finishing diets. The National Research Council reports lower energy values for barley than for corn. The authors concluded, however, that their data suggest there were no differences in net energy value between corn and barley grain. (Grove et al. 2008. Proc. Western Section ASAS. 59:326)

Effect of BCS on Reproductive Performance

In a presentation at the 2007 Applied Reproductive Strategies Conference, Rick Funston, Univ. of Nebraska scientist, reviewed the impact of nutrition on reproductive performance in beef cattle. He noted that body condition score (BCS) of females at calving is correlated with a number of economically important traits, as shown in the table.

As shown below, performance and income are markedly compromised in cows that calve in a body condition score lower than 5. Although not shown here, feeding cows to a BCS above 6 is a waste of feed resources and money, and can reduce reproductive performance, especially for cows at a BCS of 8 or 9. (Funston, R. 2007. Proc., Applied Reproductive Strategies in Beef Cattle, Sept. 11-12, 2007, Billings, Montana)

Efficiency did not cost growth in Angus bulls

Feed accounts for a significant proportion of commercial beef production costs, as much as 60-65 per cent of total costs. Consequently, improving feed efficiency could enhance profit margins. Feed conversion ratio (FCR; lb feed/lb. gain) is commonly used in evaluating feed efficiency, but FCR has been shown to be negatively correlated with mature size. Therefore, selection for improved FCR may result in an undesirable increase in cow herd mature size. The objectives of this California State Univ. Chico study were to: 1) determine the relationship between residual feed intake (RFI) and growth performance, and 2) characterize low, moderate, and high RFI cattle for growth performance, growth and ultrasound carcass EPDs, and value indices. RFI is the difference between an animal’s actual feed intake and its predicted intake. Therefore, a lower or negative RFI reflects a more efficient animal. In this study, 91 spring-born Angus bulls were consigned to a 112-day central bull test. Individual feed intake and body wt. gains were collected over a 62-day period. RFI was calculated for each bull. RFI values were used to classify bulls into efficient (RFI = -3.0 lb/day), marginal (RFI = 0.1 lb./day), and inefficient (RFI = 2.4 lb/day).

There were no significant differences among RFI groups for birth wt., weaning wt., yearling wt., or milk EPDs. Moreover, there were no significant differences among RFI groups for ultrasound carcass EPDs or value indices. Inefficient bulls exhibited significantly greater (P<0.05) FCR than marginal bulls (7.43 vs. 6.98) and efficient bulls had the lowest (P<0.05) FCR of the three (6.16). Correlation of RFI with avg. daily gain and final wt. were not significant. The correlation of RFI with FCR was statistically significant, supporting the results of the RFI groups’ analysis. The authors concluded that phonotypic selection for improved RFI may improve feed efficiency without adversely affecting growth performance. (Cardin et al. 2008. Proc. Western Section ASAS. 59:53)

Grain Processing Method Affected E. coli 0157 Prevalence in Feedlot Cattle

Kansas State Univ. researchers used 40 feedlot heifers to evaluate the effects of grain type (sorghum or wheat) and grain processing method (dry-rolled or steam-flaked) on the prevalence of the bacterial pathogen, E. coli 0157, in cattle. The 40 heifers in this experiment had previously tested positive for E. coli 0157. Fecal and rectal swab samples were collected for four weeks to monitor shedding of the pathogen. The average prevalence of E. coli 0157 was markedly lower in the two dry-rolled grains (approximately 25%) than in the two steam-flaked grains (60 to 75%). The author concluded that grain processing methods, such as dry rolling, that increase the amount of starch delivered to the hindgut may be a simple and useful strategy for reducing the prevalence of E. coli 0157 in cattle. (Fox, T. 2007. Kansas State Univ. Beef Research Highlights)

The authors are animal scientists at Michigan State University in East Lansing, Michigan, U. S. A.

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