Beef Cattle Browsing – October 2012

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.


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



We’re often told we should turn back the clock and produce cattle for beef the way we used to. What would be the impact if we did away with steroid growth implants, ionophores in feed, hormones in feed, and beta agonists ? This question was investigated in a recent study. The effects?  In the U. S., to produce the same amount of beef we’d need:

  • 11.8% more cattle in the U.S. beef herd,
  • 10.4% more fed cattle slaughtered,
  • 10.6% more tons of feed,
  • 10.0% more acres of land for grazing and growing feed,
  • 4.2% more gallons of water for producing more feed and maintaining more cattle.

And, in the process, 9.8% more metric tons of carbon dioxide equivalent would be produced. (J. Animal Sci. 90:3527; Washington St. Univ., Iowa St. Univ.)

Hereford steers initially averaging 416 lb (in 2007) or 458 lb (in 2008) were grazed on Texas high plains wheat pasture, stocked at slightly over 1 acre per head, with the following treatments:

  • distillers dried grains (SDDG) @ 0.5% body weight (about 2.7 lb/day).
  • dry-rolled corn (SDRC) @ 0.5% body weight (about 2.7 lb/day), or
  • non-supplemented controls (SCON).

Supplements were fed 6 days/week. Depending on the year, grazing began in December or January and concluded in April or May; grazing period averaged 128 days. All groups gained exceptionally well on wheat. The SDDG group gained 3.08 lb/day, significantly more than either SDRC (2.88 lb/day) or SCON (2.84 lb/day). However, even the SDDG group used supplement inefficiently, requiring 11.5 lb supplement/lb added gain.  There appeared to be some substitution of both supplements for forage consumption, especially SDRC. However, both supplements resulted in greater grazing days/acre and more total gain/acre. Even though protein content of wheat pasture is high, performance was greater with a medium-protein, medium-energy, low-starch supplement than a low protein, high-energy, high-starch supplement which did not improve performance over non-supplemented controls.

After grazing, cattle were placed in a feedyard and stepped up to a steam-flaked corn ration with one-half of each of the three stocker treatment groups receiving either 35% DDG (FDDG) or no DDG (FSFC). Cattle were fed an average of 95 days when estimated fat cover was ½ inch. There were no significant differences among stocker treatment groups in ADG during finishing, although the SDRC-supplemented group tended to be higher, but the SDRC group was significantly more efficient. There were no significant differences for final weight or any carcass traits.

Considering just the finishing phase, on a carcass-adjusted basis FSFC, compared to FDDG, had significantly higher ADG, feed efficiency, and final weight. [FSFC also were higher in total (stocker + finishing) weight gain.] FSFC had higher hot carcass weight, dressing %, fat thickness, and numerically higher (lower % lean) Yield Grade than FDDG; ribeye area and marbling score did not significantly differ.

As controlled studies and industry observations have shown over the years, nutritional management resulting in higher performance during earlier production phases may be offset, at least somewhat, or even reversed in later phases. So, supplementation decisions for stockers should consider whether ownership is retained for finishing. (J. Animal Sci. 90:2381; Texas A&M Univ., West Texas A&M Univ.)

A study analyzed 290,866 cattle hauled over 880 miles in 6152 loads. About 0.01% became lame, 0.02% unable to walk, and 0.01% died onboard. Factors which increased incidence of those conditions were:

  • calves and market cows/bulls, compared to feeder and finished cattle
  • hauled more than 30 hours
  • temperatures <5 deg. F or >85 deg. F
  • animals losing >10% of body weight
  • space per head was low, especially in belly and upper deck of trucks
  • space per head was high in upper deck
  • decreased driving experience of trucker.

Factors increasing body weight loss were:

  • loaded in afternoon and evening vs. night and morning
  • drivers having < 6 years of experience
  • higher temperature
  • more time on truck
  • market cows/bulls>calves>feeders>finished.

(J. Animal Sci. 90:3630 and 3640; Agriculture and Agri-Food Canada at Lethbridge, Univ. of  Manitoba)

Sometimes we tend to think calves are the income from a beef cow herd, but calves are only part of the story. In a typical herd where replacement heifers are saved for breeding about 50% of income is from steer calves, 30% from heifers not retained for breeding, and 20% from marketed breeding stock. Producers need to pay attention to factors affecting value of marketed breeding stock. That may mean such things as increasing sale weight and body condition, if done economically, and marketing when prices are higher. Fall (especially October) has historically been the worst time to sell packer cows and bulls because marketings are typically highest at that time.

A group of 433 Angus X Hereford females, which had calved at least twice, were evaluated for chute behavior score and chute exit velocity.  Cows were scored from 1 (calmest or slowest) to 5 (most nervous or fastest). Temperament scores were calculated by averaging the two evaluations. Cows with temperament scores > 3 were classed as aggressive. Aggressive cows had reduced rates of pregnancy (89% vs. 95%, P<.03) and calving (85% vs. 92%, P<.04). Calf weaning weight varied by only 2 lb but, because of reproductive differences, calf weight per cow exposed tended to be lower (by 35 lb, P<.08) for aggressive cows. The authors concluded that temperament was important in cow reproduction and recommended that aggressive individuals should be considered for culling on that basis.

In another study, 88 Angus X Hereford heifers averaging 206 days of age were weighed and evaluated for temperament score. Heifers in one-half of each temperament group were acclimated to handling three times weekly as follows:

  • beginning 11 days after weighing, heifers were gathered from pasture and walked through a handling facility but not restrained and then turned back to pasture;
  • beginning a week later, heifers were restrained in a chute for 5 seconds and turned back;
  • beginning after another week, heifers were restrained for 30 seconds and turned back;
  • beginning after another week, heifers were restrained for 30 seconds and then turned out into the facility lot for one hour and then back to pasture.

The other one-half of the heifers was left undisturbed on pasture during each of the acclimation procedures.

All heifers were weighed and assessed for temperament score 40 days and 200 days after initial weighing and scoring.  ADG did not significantly differ (p<0.37) between groups. Acclimated heifers had lower (P<0.02) velocity scores after 200 days. By day 200, acclimated heifers had 60% vs. 38% (P<0.01) puberty. Subsequent pregnancy rates (87% vs. 78%) did not differ significantly (P<0.26). The authors concluded that acclimation to handling could improve temperament and increase attainment of puberty. EDITOR’S NOTE: No data were provided as to the time and expense required to run heifers after weaning through a handling facility for a total of 12 times over 28 days. (J. Animal Sci. 90:3547, Oregon St. Univ.)

A study was conducted to assess possible genetic-environmental interaction on weaning weight. Interaction occurs if traits are expressed at different levels in different environments. American Angus Association records were used to compare the adjusted weaning weights of calves in the Northwest, NW (Washington, Oregon, Idaho, Montana, and Wyoming) to calves in the Southeast, SE (Arkansas Louisiana, Mississippi, Alabama, Tennessee, North Carolina, South Carolina, Georgia, and Florida). A total of 588 sires had calves in both regions. Analysis was confined to at least 20 calves in a contemporary group and no single-sire groups, which resulted in 884,465 records. Distribution of calving was grouped as follows: fall (Sep-Nov), winter (Dec-Feb), spring (Mar-May), and summer (Jun-Aug).

Weights tended to average higher in NW than SE. Heritabilities were similar across environments, ranging from 0.29 to 0.35 for direct genetic effect on weaning weight and 0.12 to 0.16 for maternal genetic effect on weaning weight. (These values are similar to what have been found in numerous studies.) Possible genetic-environmental interaction was measured by the magnitude of genetic correlation (high correlation = low interaction, low correlation = high interaction). Correlations were high (averaging 0.80 for SE and 0.93 for NW) between calving seasons in the same region. Depending on calving season, correlations between regions were lower, ranging from 0.65 to 0.86, with the lowest correlation being between SE winter and NW spring for maternal genetic effect. The authors concluded that rankings of sires could be influenced by region/calving season and that some attention to genetic-environmental interaction is warranted. (J. Animal Sci. 90:3368; Univ. of Georgia, Polish Institute of Genetics and Animal Breeding)

The Texas Animal Health Commission has ruled that, starting January 1, 2013, all sexually intact adult cattle must have an approved individual identification device in place upon any change of ownership. Also, TAHC has announced plans to revise trichomoniasis regulation procedures to allow testing pooled samples of up to five bulls. Details on both subjects can be accessed on the commission website,

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