Beef Cattle Browsing – April 2015


Several research studies have shown the Mediterranean Diet can help with problems associated with the heart, diabetes, and hypertension. There is no one Mediterranean diet, but they are generally characterized by higher than typical amounts of fresh fruits and vegetables, whole grains, beans, nuts, olive oil, fish, and little if any red meat. However, a recent report by the 2015 Dietary Guidelines Advisory Committee found that red and processed meats are higher in most Mediterranean-style diets than in some other diets recommended to improve health, such as DASH (Dietary Approaches to Stop Hypertension) and the USDA Dietary Guidelines. More evidence is accumulating that no diet is a miracle and that red meat and animal fats are not as harmful as many once thought and, unfortunately, still do, including some “experts.”


Genetic selection for many traits has been greatly advanced by breed-wide genetic evaluation through Expected Progeny Difference. When EPD started, and for a good while after, valid comparisons were restricted to those within a breed. Then the U. S. Meat Animal Research Center at Clay Center, NB, developed adjustments to compare EPDs across breeds. (The latest across-breed adjustment factors can be accessed at, where you can also find current breed EPD averages and comparisons of breeds.)

Now, several breed registry associations have agreed to participate in a joint analysis of most traits, conducted by the American Simmental Association, resulting in one genetic evaluation; thus EPDs can be compared directly across these breeds without applying any adjustment factors. Comparisons are available not only for purebreds but also crossbreds and composites of known breed percentage. Breeds involved are Chianina/ChiAngus, Gelbvieh, Limousin, Maine-Anjou, Red Angus, Shorthorn, and Simmental. Other breeds could be included in this joint analysis or other joint efforts might develop.


Some general and industry news sources recently reported on research indicating that dust from beef feedyards contained antimicrobial products and DNA from bacteria with antimicrobial resistance. However, a subsequent response by three university veterinarians found three problems with the findings:

– bacterial DNA were isolated from dust but the data did not show if any living bacteria were present,

– the DNA posed no direct threat to human health because it would not reconstitute into harmful organisms,

– concentration of antimicrobials in the dust was extremely low, tightly bound to the dust particles, and will be degraded in the environment.

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A study was made using 336 certified natural black-hided steers from two sources. Cattle were shipped 648 miles or 429 miles to an experiment station feedyard. Upon arrival, steers averaged 834 lb, having shrunk 4-5% from preloaded weight, and were vaccinated for clostridial diseases, IBR, PI3, BRSV, BVD, and treated for internal and external parasites. Cattle were then divided into three groups for finishing on the same 93% concentrate ration:

– natural (NAT), received no anti-biotics, growth implants, or beta agnonist

(zilpaterol, Zilmax®), and if antibiotic treatment was deemed necessary, they were removed

from the trial;

– conventional (CON), implanted with 40 mg of estradiol and 200 mg of TBA, daily fed

33 and 9 mg/kg of monensin and tylosin, and treated with antibiotics if necessary;

– conventional plus (CON+), treated same as CON plus fed zilpaterol for the last 20

days on feed, withdrawn from feed for 3 to 5 days before slaughter.

Cattle were weighed every 28 days and on day 84 projected into slaughter groups based on predicted slaughter weight and a visual appraisal of fat cover.

Statistically significant differences existed as follows:

– CON+ gained 3.8% faster and 5.3% more efficiently than CON,

– CON gained 32.8% faster and 26.7% more efficiently than NAT,

– CON+ carcass weights were 18 lb heavier than CON and 101 lb heavier than NAT,

– CON+ had 10% units more Yield Grade 1 and 22% units fewer YG3 than CON,

– CON+ had 12% units more USDA Select, 5% units fewer Low Choice, and 8% units

fewer mid-Choice and higher than CON.

There was no significant difference in feed consumption among the three groups and no significant differences in carcass traits between CON and NAT.

Inclusion of the beta agonist improved finishing performance and carcass leanness over conventional management but decreased carcass marbling. So, use of beta agonist should consider the relative value of the magnitude of differences in performance, Yield Grade, and Quality Grade. If effectively marketed, natural beef may be valued higher than conventionally-produced product. But any price bonus must be weighed against notably lower weight gain, poorer feed efficiency, and less pounds of product. NOTE: As of late April, zilpaterol is not being marketed. Research and field observations currently being conducted may result in its being marketed again. Another beta agonist, (ractopamine, Optaflexx®) is available for finishing cattle.

(J. Animal Sci. 93:1340; Oklahoma St. Univ.)


As might be expected, cattle native to hot climates are better adapted to such conditions, and are not as well adapted to cold climates. In general, these types tend to have shorter hair coats than types native to cold climates. There are plenty of types and breeds available for production in hot climates. However, they are not the highest in milk production.

Previously, a slick-hair gene was discovered in Senepol, native to the U. S. Virgin islands, and some criollo-types breeds in Central and South America. Subsequently, the location of the gene was established and characterized as the SLICK locus, acting as a simple single dominant. Beginning in 1990, Holstein were crossed with Senepol. By two subsequent backcrosses to Holstein, 7/8-1/8 Holstein-Senepol were produced, which contained  the SLICK gene.

In comparison with Holstein (15/16 or higher) without the SLICK gene, when placed outside in drylot with cloth shade SLICK cows had lower respiration rate and less increase in rectal temperature. Sweating rate was higher for SLICK. Also, during summer, when milk production declined compared winter, reduction was less in SLICK cows. As more genes are identified perhaps such procedures as used in this study, along with genomic techniques, could lead to higher heat tolerance without sacrificing some other performance attributes including, but not limited to, carcass marbling.

(J. Dairy Sci. 97:5508; Univ. of Florida, USDA-ARS Animal Genomics and Improvement Laboratory)


Some advocate elimination of animal products, especially meat and particularly beef, from human diets. A typical reason given is that animals are less efficient than plants in using resources to produce food.  And, among animals, cattle are characterized as less efficient than hogs, poultry, or fish. But this is usually based on differences in efficiency of conversion of grain.

Simple comparisons of grain conversion ignore the fact that beef cattle fed for slaughter are managed on high-grain diets for roughly only about one-fourth of their life. In beef cow herds and the growing process before finishing there is little use of grain. So, it is estimated that, across the entire production cycle, beef cattle spend only around 11-12% of animal-days per year in feedyards. Adjusting for differences in diet composition between production phases results in grain amounting to 16-17% of animal-feed days. Contrast this to modern pork, poultry, and farmed-fish businesses, where grain and other concentrates are the nutritional base for the entire production cycle.

If only 16-17% of animal-feed days is from grain, what is the source of the other 83-84%? It is from forage, byproducts, and slight amounts of mineral-vitamin supplements. What byproducts are used in animal feeds? Only a partial list would include: corn gluten feed, gluten meal, distillers grains, and hominy feed; wheat red dog, mill run, middlings, and wheat bran; sorghum distillers grains; barley distillers grains; rice bran; soybean meal and hulls; canola meal; whole cottonseed and meal; fruit and vegetable peels, seeds, pomace, etc.; citrus juice; sugar beet pulp; and almond hulls.

What would be done with these byproducts if not used in animal feed? Put them in landfills? There are not enough landfills to handle the mass of material.  Some could be burned, composted, or fermented to produce electricity or put back in soil. But all these procedures would generate some carbon dioxide. Better to use this material to produce milk and meat. Feeding byproducts to animals is the most economically and environmentally sustainable way of disposal.

(Feedstuffs Magazine, 3/31/15; summarized by permission)


Charolais X Gelbvieh Balancer heifers averaging 255 days of age and 394 lb were divided into four groups:

– non-implanted controls (CON);

– 200 mg implant of trenbolone acetate (TBA);

– 40 mg TBA + 8mg estradiol (TBA+E);

– 36 mg zeranol (ZER).

Heifers were weighed when implanted (day 0) and on days 106, 195, and 220. Reproductive tract scores (RTS) were determined by ultrasonography on days 106 and 195. Estrus was synchronized on day 195, when heifers averaged 450 days of age. Estrous behavior was monitored by radiotelemetry and heifers were AIed 10-19 hours after onset of estrus followed by exposure to clean-up bulls for 28 days. Pregnancy was diagnosed by ultrasonography on days 278 and 299. Results were as follows, with any differences being statistically significant:

– TBA+E ADG and weight at breeding were higher than the other groups, among which there was no significant difference;

– lower % of ZER were classified as RTS cyclic on day 106 than CON and TBA, with TBA+E intermediate;

– there were no differences in RTS on day 195;

– TBA had more mounts during estrus;

– duration of estrus did not differ;

– pregnancy rate did not differ.

The authors concluded that “implant strategy did not decrease pregnancy rates”. NOTE: some earlier research indicates some negative effects on reproduction.

(2014 Am. Soc. of Anim. Sci. Southern Section Meeting, abst. no. 69; Univ. of Arkansas)


The annual Grassfed Beef Conference will be held on the campus of Texas A&M University on May 28 and 29. Details can be accessed at

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