Beef Cattle Browsing is an electronic newsletter published by Texas A&M AgriLife Extension, Department of Animal Science at Texas A&M University. This newsletter is a free service and is available to anyone interested in beef cattle. Media, feel free to use this information as needed and cite Texas A&M University Beef Cattle Browsing Newsletter, Dr. Steve Hammack.
ETHANOL FOR FUEL MAY BE REDUCED
The Energy Independence and Security Act (2007) required certain levels of renewable sources be incorporated into fuels, with levels increasing each year. The level of ethanol mandated for 2014 is 14.4 billion gallons. Based on several factors, the Environmental Protection Agency has proposed reducing that by approximately 9 percent. Less corn for ethanol production would mean more corn available for livestock feeding. http://www.epa.gov/otaq/fuels/renewablefuels/documents/420f13048.pdf
GROWING HEIFER RFI EFFICIENCY VS. BREEDING PERFORMANCE
Residual Feed Intake (RFI) is being increasingly used as a measure of feed efficiency. Over two years, 115 Bonsmara heifers (a tropically-adapted Bos taurus breed of 5/8 Africander, 3/16 each Hereford and Shorthorn) were weaned at average of 202 days of age, backgrounded, and placed in drylot at average 280 days of age and 642 lb on a 70%-roughage ration for a 70-day growing period. During that time, individual feed consumption and performance traits were measured. Based on that 70-day period, 24 heifers with the lowest RFI (more efficient) and 24 heifers with the highest RFI (less efficient) were retained for breeding. Heifers diagnosed pregnant (20 low RFI and 22 high RFI) were then adapted to an all-roughage ration starting at 155 days of gestation and then feed consumption, weight gain, and condition scores were measured during a 77-day post-breeding period.
High efficiency heifers (low RFI) were heavier at weaning by 44 lb. During the post-weaning growing trial, high efficiency heifers (low RFI) were significantly different from low efficiency (high RFI) heifers as follows:
- ate 19% less (4.4 lb/day);
- had similar weight gain;
- had higher gain:feed (23%);
- had smaller (0.4 sq in) ribeye area at end of trial.
During the post-breeding trial, pregnant females that had low RFI (more efficient) during the post-weaning trial were significantly different from those with high post-weaning RFI (less efficient) as follows:
- ate less 17% less (5.1 lb/day);
- spent less time (26%) at the feeder;
- had lower RFI (more efficient);
- had lower heart rates (7%);
- had similar initial and final body weight and body condition.
No other traits differed significantly except there were tendencies for high efficiency heifers to have more fat cover at the start of growing, but increase less in fat cover during growing, and have higher intramuscular fat after growing. There was no significant difference in calving date between the two efficiency groups.
Based on phenotypic correlations, the lower feed-consuming, high efficiency (low RFI) heifers during growing continued to exhibit those characteristics during gestation. The authors concluded that heifers of high efficiency during growing are also more efficient as bred heifers, with little effect on growth, body composition, calving date, or calf birth date.
(J. Animal Sci. 91:5353; Texas A&M University)
EFFECT OF GRASS/FORAGE FEEDING ON BEEF NUTRIENTS AND EATING QUALITY
A review of 18 U. S. scientific papers was conducted to evaluate finishing cattle on grass/forage (referred to below as GFF) versus traditional high-grain rations. Important findings were:
- cuts from GFF beef are lower in total fat;
- both types of beef contain omega-3 fatty acids;
- one of three papers reported GFF beef to be significantly lower in cholesterol;
- GFF beef is higher in omega-3 fatty acid but the level is very low in both types;
- both types of beef contain a variety of key nutrients;
- some studies, but not all, reported GFF beef to be less tender;
- most studies found no difference in juiciness;
- external fat is more yellow in GFF beef;
- most U. S. consumers prefer the flavor of grain-finished beef;
- some U. S. consumers, and more consumers in other countries, prefer GFF beef flavor.
While the U. S. market for beef finished on grass or forage is relatively small it is growing.
(Meat Science 96:535; VanElswyk Consulting, NCBA)
EFFECT OF WEANING AGE AND FEED SOURCE ON PERFORMANCE, CARCASS, AND ECONOMICS
200 Angus and Angus X Simmental calves were either early weaned (average = 133 days of age) or normal weaned (average = 233 days of age). Calves were randomly assigned to five treatment groups:
- early weaned, drylotted on high-starch (67% corn) ration;
- early weaned, drylotted on high-fiber (50% corn bran-25% soyhulls) ration;
- normal weaned, creepfed high-starch (82% corn);
- normal weaned, creepfed high-fiber (60% corn bran-30% soyhulls);
- controls, normal weaned, no creep.
All calves were then finished on 28% corn, 25% corn gluten feed, 45% corn husklage to approximately 1/2 inch fat cover. Carcasses were priced on a value-based grid.
During the calf phase, early-weaned on the starch ration ate less and were more efficient than those on the fiber ration. Early-weaned gained slightly more than creepfed and both gained considerably more than controls. In the finishing phase, early-weaned consumed the most feed and creepfed the least. Early-weaned gained less and were less efficient. Early-weaned had highest degrees of marbling, highest USDA Quality Grade, and highest percent qualifying for Certified Angus Beef; controls were lowest in those traits. Yield Grade differed little between the five treatments.
If marketed at normal weaning time, nutritional cost and total cost was highest for early weaned and lowest for controls. The corn-based creep and finishing ration cost more than fiber-based. If fed and marketed on a carcass value-based grid, cost of gain and total cost was highest for early-weaned and lowest for controls. Profit per head was:
|GROUP||MARKET @ WEANING||MARKET @ CARCASS|
|Early wean, corn||$86||$148|
|Early wean, fiber||$101||$187|
As this study shows, ethanol co-products can yield performance and carcass results similar to high-grain feeding but with lower cost and higher profit, depending on availability and price of co-products.
As has been found in some other studies, early weaning can increase calf gain and final carcass quality grade. Also, early weaning may improve reproductive performance during periods of restricted feed supply and could possibly allow more cows to be maintained on the same forage resource. However, in this study the advantages of early weaning were more than offset by increased cost, resulting in lower profit at both weaning and with retained ownership.
(Prof. Anim Sci. 29:469; Univ. of Illinois)
Resistance of disease-causing organisms to antibiotics continues to increase. A recent report in the British medical journal Lancet addressed this topic. The report was the result of a review conducted by a panel of 26 international experts in the field; 386 literature references were included. The conclusion was that antibiotic resistance at this point is largely due to: 1) unnecessary ineffective prescriptions by physicians for self-limiting bacterial and viral infections, 2) patients expecting to receive antibiotics for such things as simple colds, 3) lack of prescriptions required for human use in some parts of the world, and 4) use in livestock for growth promotion.
The report indicates that, even though on a volume basis the largest amount of antibiotics is used in livestock production, the exact contribution to resistance from that use is not known. However, recent research has found transfer can occur of resistant genes from animals to humans. As more research is done more will be understood about coping with antibiotic resistance, from all sources. Some in the livestock industry foresee at least the limitation, if not elimination, of antibiotics for promoting growth.
(The Lancet online, published 11/17/13)
SURVEY OF TRANSPORTED SLAUGHTER COWS AND BULLS
A survey was conducted of 113 loads of beef and dairy cows and bulls delivered to 23 packing plants in 12 states. All loads arrived with per-head space allotment consistent with American Meat Institute Foundation guidelines. Some notable findings:
- in 27% of beef and 29% of dairy loads ≥ 3% of cattle slipped during unloading;
- electric prods were used in unloading 32% of beef and 15% of dairy loads;
- fewer cattle had horns, brands, or mud/manure contamination than in a 1999 survey;
- 44% of beef were black, 32% red, and 93% of dairy were Holstein pattern;
- only 2.9% had cancer eye compared to 8.5% in a 1994 survey and 4.3% in 1999;
- dairy lameness went up from 39% in 1999 to 49%, beef declined by 27% to 16%;
- Body Condition Score averaged 4.5 (1-9 beef scale) in beef cows and 2.5 (1-5 dairy scale) in dairy cows;
- there were no udder defects in 90% of beef cows and 76% of dairy cows;
- 72% of beef and 63% of dairy had no defects.
(J. Animal Sci. 91:5026; Texas A&M Univ., North Dakota St. Univ., California Poly Tech Univ., West Texas A&M Univ., Pennsylvania St. Univ., Univ. of Georgia, Univ. of Florida)
DNA TESTING FOR GAIN AND MARBLING
American Angus Association-Certified Angus Beef® has available the GeneMax™ test to predict post-weaning weight gain and marbling, applicable in ≥ 75% commercial Angus cattle only. Results have been reported of a field study on 173 steers fed for 143 days. Steers were DNA-sampled at the start of feeding. In the GeneMax test, calculations are made for GMX gain, GMX marbling, and overall GMX score, combining weight and marbling. The report divided the results into four groups based on GMX score: HI, Mid-HI, Mid-LO, and LO.
GMX gain score predicted wide range between groups, but actual ADG did not differ significantly. GMX marbling score also predicted wide range between groups, and the HI GMX group proved to be significantly higher in actual marbling score than Mid-LO and LO groups. Carcass value per head was: HI = $1924, Mid-HI = $1926, Mid-LO = $1893, LO = $1894. Cost of the test is $17/hd, a little over half of the difference in carcass value in this study for the top two GMX groups over the bottom two GMX groups.(www.cabpartners.com/genemax/results.php)
THERE’S MORE TO A STEER THAN MEAT
Based on current average carcass weight and price, a steer carcass is valued at roughly $1750. We sometimes forget there is some value in what is removed to produce a dressed carcass. Current value of hide and offal from that average steer is close to $200. That is an important part of the value of a slaughter steer to a packer, and is often the difference between profit and loss.