Beef Cattle Browsing – May 2005

Beef Cattle Browsing

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

May 2005

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.

Arkansas and Kansas researchers collaborated on a review of 39 research papers dealing with weight shrink during transportation. Shrink comes from two sources, loss of fill (feces and urine) and tissue shrink. Shrink increases as ambient temperature increases, and so does the fraction of total loss due to tissue shrink. Shrink during the first three to four hours averages about 1 % of body weight per hour, but after10 hours is as little as 0.1 % per hour. Handling procedures influence shrink; higher shrink occurs when there are more problems in gathering, sorting, loading, etc. Nervous, excitable cattle shrink more. There is no consistent pattern in transportation shrink associated with differences in diet before shipping, nor between preconditioned and fresh-weaned calves. (However, preconditioning has been shown to reduce the adverse effects on health/performance due to transportation shrink and other stresses.) Allowing cattle to graze before shipping reduces shrink during the early shrink period. There is a tendency for less shrink in cattle fed ionophore feed additives before shipping. Cattle shipped long distances and shrinking 7% to 9% recover about one-half of lost weight when allowed to eat and drink after shipping. But the remaining one-half of weight requires around 10 days for recovery. Finally, as the amount of transit shrink increases, so does the level of bovine respiratory disease. (Prof. Anim. Sci. 17:247)

Missouri researchers developed Angus and Angus-cross heifers to determine costs in developing from weaning to first calving. Heifers born in the fall of 2000 were weaned the next April, bred in November, and calved in the fall of 2002. Heifers averaged 448 lb at weaning and 815 lb at the beginning of breeding when average age was 13.5 months, at which time all heifers were cycling. Heifers were synchronized, artificially inseminated, and then turned out with cleanup bulls. Pregnancy rate was 71% to AI and 94% overall. Cost of development (including pasture, feed, labor, vaccination, synchronization, AI, clean-up bulls, pregnancy testing, and cost of open heifers) was $400.23 per heifer. At current prices for 450 lb heifers, you would have about $1000 tied up in a heifer ready to calve as a two-year-old. (J. Animal Sci. 82, Suppl. 1:288)

For some time, the ratio of calf weaning weight to dam’s weight has been employed as a measure of production efficiency. USDA researchers in eastern Montana used a composite population formed from 50% Red Angus, 25% Charolais, 25% Tarentaise to study the effects of genetic selection based on this ratio. A closed genetic selection line based on the ratio was compared to a randomly selected control line. Selection on this ratio attempts to simultaneously increase weaning weight while decreasing cow weight. However, the genetic correlation in this study between calf weight and cow weight was 0.91. Perhaps largely because of this relationship, selection response after about 2.5 generations led to the conclusion that “results contraindicate use of the ratio as a selection criterion”. Interestingly, at this location (13.4 inches average precipitation, stocking rate of 35 acres/cow) average cow weight in the control line declined as selection progressed over time. The authors speculated that natural selection in this environment may have favored smaller body size. (J. Animal Sci. 83:794)


Illinois researchers evaluated factors affecting carcass value and profit in 192 early-weaned Simmental-cross steers over a period of four years. Steers were harvested at approximately 14 months of age. Production costs were factored in, including annual cow cost, veterinary, medicine, labor, feed, yardage, and interest. To even out yearly variation, feed and carcass grid prices were averaged over five years. The following carcass premiums/discounts were applied ($/cwt carcass): Prime (+$5.62); premium Choice (+$1.50); low Choice ($0.00); Select (-$8.90); Standard (-$17.72); YG 1 (+$2.46); YG 2A (+$1.31); YG 2B (+1.11); YG 3A (-$0.12); YG 3B (-$0.19); YG 4 (-$14.16); YG 5 (-$19.56); 950 lb to 1000 lb carcass (-$11.39); > 1000 lb carcass (-$19.71). Differences in total carcass value were explained as follows: 57% due to carcass weight, 12% to marbling, and 10% to Yield Grade. However, carcass weight explained only 9% of variation in profit while differences in marbling accounted for 30%, feed consumption 14%, average daily gain 12%, and Yield Grade 12%. (J. Animal Sci. 82, Suppl. 1:273)

At one time “Durham” was another name commonly used for Shorthorn cattle. That name has been revived. The American Shorthorn Association has announced a new composite, Durham Red, to consist of a combination of Shorthorn and Red Angus, ranging from 1/4 to 3/4 of each breed. The association will begin recording Durham Reds this fall. (Am. Shorthorn Assoc.)

Dr. Ted McCollum, Texas A&M Research & Extension Center – Amarillo, points out that mandatory COOL is still in place. Implementation was delayed until September 2006, when retailers must have covered items labeled. Packers and wholesalers will have to begin documenting beef in the summer of 2006, so calves born this spring and later will most likely fall under COOL regulations. Beginning with marketings this fall, producers may be asked to document country-of-origin. Records should be available to verify the number of calves born this year and the number of cows in herds during the calving season in order to validate that the producer actually had enough cows to birth and raise the number of calves being sold. Various forms of documentation will probably suffice, including calving records, branding/processing records, etc. However, a bill has been introduced in Congress the first week of May calling for voluntary country-of-origin labeling to supplant the mandatory program set to go into effect in September, 2006. The fate of this bill may not be known for several months, so producers should go ahead and prepare as if the legislation was never proposed. And, even if COOL is not mandatory, there may be opportunities for cattleman to document their calves and be paid for it under a voluntary system. (Ted McCollum, )

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