Beef Cattle Browsing – May 2007

Beef Cattle Browsing

Editor: Dr. Stephen Hammack, Professor & Extension Beef Cattle Specialist Emeritus

May 2007

This newsletter is published by Texas AgriLife Extension – Animal Science. Media, feel free to use this information as needed and cite Texas A&M University Beef Cattle Browsing Newsletter, Dr. Steve Hammack.

Data from Certified Angus Beef Licensed Feedlots sheds some interesting light on this subject.  Records were available on almost 81,000 calves and almost 70,000 yearlings.  There was essentially no difference between the two in either Quality Grade or Yield Grade. The yearlings graded 58.8% Choice or Prime, compared to 58.1% for calves. Yearlings had 35.1% Yield Grade 1 or 2, compared to 34.7% for calves. Percent qualifying for Certified Angus Beef was 13.5 for calves and 13.1 for yearlings. What caused carcasses to fail to qualify?  Over 90% of the failures were due to inadequate marbling, leaving less than 10% due to all other factors (ribeyes less than 10 or over 16 sq in, excessive maturity, blood splash in the ribeye, fat cover over 1 inch, carcass weight over 1000 lb, dark cutter, dairy-type conformation, excessive hump height, or coarse marbling). Yearlings did produce heavier carcasses, 833 lb versus 784 lb. It should be noted that some controlled research studies have found higher marbling from calf feds. (

Researchers at the University of Kentucky, Louisiana State University, and the University of Florida collaborated in a review of over 100 papers evaluating genetic effects from sires on calving difficulty. In general, they found:

1) On Bos taurus females, straight Bos indicus sires (in most studies represented by Brahman) increased dystocia compared to Bos taurus sires.

2) Dystocia from Brahman sires was no higher than from other straight Bos indicus sires, such as Indu-Brazil and Nellore.

3) Dystocia from Bos indicus-derivative sires (Brangus, Santa Gertrudis etc.) was generally no higher than from Bos taurus sires.

4) The Bos indicus sire effect was largely related to heavier birth weights, possibly due to longer gestation length along with highest heterosis from Bos indicus X Bos taurus matings.

5) Dystocia was higher from male than female calves. This effect was most pronounced in Bos indicus sires compared to Bos taurus sires. (Prof. Anim. Sci. 18:18)


Compared to the study of nutrition of confined animals on prepared rations, grazing animals present significant problems. It is not easy to determine what they’re consuming, how much, and what use is being made of the consumed material. An Israeli researcher examined over 60 publications from all over the world to determine the possible use of some physiological measures to determine energy expenditure and balance in grazing animals. He found that oxygen consumption is a good  measure of energy expenditure (also called heat production), and that heart rate can accurately predict oxygen consumption. (Heart rate can be measured relatively easily compared to oxygen consumption.) Also, heart rate and energy expenditure are closely related to energy consumption. Energy cost of animal activity can be estimated using motion sensors and GPS. It was concluded that improved techniques, particularly microelectronic devices to measure heart rate, can increase knowledge of energy factors in grazing animals. (J. Animal Sci. 85:1213)


Expanded ethanol production is yielding more byproducts that can be fed to cattle, such as distillers grains. So far in the beef industry the greatest use of such material is primarily in feedyards. Two recent research studies investigated applications for grazing yearlings and suckling calves.

Distillers Grains for Grazing Yearlings
Nebraska researchers wanted to know what use these products might have for growing cattle on pasture. They used yearling British-Continental crossbred steers initially weighing about 650 lb. A treatment group (TRT) had free-choice access to dried distillers grains (DDG) on Sandhill pasture from early June to early August. Controls (CON) were not fed.

Consumption of DDG averaged 11 lb/day. TRT gained 2.8 lb/day and CON gained 1.9 lb/day. Forage consumption was estimated to be about 30% less by TRT. So, for every CON animal, about 1.4 TRT animals could be run on the same pasture area. After grazing, all animals went to a feedyard. TRT were harvested 14 days before CON. There were no statistically significant differences between the two groups in final weight, ADG, or carcass characteristics. There was a tendency (P<.15) for TRT to have more Choice (67% vs 51%). The economic value of DDG was 17% over its cost for grazing and 11% over cost for finishing. The authors stressed that the use of DDG in this manner would depend on pasture cost, DDG cost, feeder cattle price, and fed cattle price. (Prof. Anim. Sci. 23:170)

Distillers Grains for Creep-fed Suckling Calves
Missouri researchers conducted a 2-year study on creep feeding. Calves and dams were divided into three groups: creeped on distillers dried grains with solubles (DDGS), creeped on soyhulls/cracked corn, and non-creeped control. The first year, calves were divided by age only. The second year grouping was by sire as well as age. In both years, creeped calves gained significantly more, 2.31 lb/day vs. 1.54 lb/day in Year 1 and 2.20 vs. 1.98 in Year 2.

There was no significant difference between the two creeps, except that total feed cost was lower in Year 2 for DDGS. However, there was no significant difference in weaning revenue between  creeped and non-creeped in either year. As has been found in numerous studies, change in body condition score of dams was not affected by creeping calves. In conclusion, distillers grains appear to be a useful material for creep fed calves, and may be less costly than some traditional feedstuffs.  However, creep feeding is often not economically beneficial because of relatively low conversion of feed to extra gain in creeped above non-creeped calves. (Prof. Anim. Sci. 23:83)

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