Submited on: 17 Jul 2014 04:57:42 PM GMT
Published on: 18 Jul 2014 04:05:56 AM GMT

  • What are the main claims of the paper and how important are they?

    a. There are potential benefits of incorporating multigenerational animals into current production schemes in order to improve traits which have been inadvertently selected against.

    b. Modern genetics may prove to be more beneficial to incorporate into breeding herds as these phenotypes are more in line with current market demands in the beef industry.

  • Are these claims novel? If not, please specify papers that weaken the claims to the originality of this one.

    Yes, these are rather novel claims.

  • Are the claims properly placed in the context of the previous literature?


  • Do the results support the claims? If not, what other evidence is required?

    Yes, I believe they do.  Different carcass traits were significantly affected by both sire groups, indicating that both have merit in an animal breeding system designed to improve overall carcass trait acceptability to the consumer.

  • If a protocol is provided, for example for a randomized controlled trial, are there any important deviations from it? If so, have the authors explained adequately why the deviations occurred?

    The authors adhered to their stated protocol throughout the manuscript.

  • Is the methodology valid? Does the paper offer enough details of its methodology that its experiments or its analyses could be reproduced?

    The statistical methodology section needs some corrections (see comments section below). Otherwise, the methodology is valid and sufficient for replication of the experiment.

  • Would any other experiments or additional information improve the paper? How much better would the paper be if this extra work was done, and how difficult would such work be to do, or to provide?

    No, I believe the manuscript is complete.  It would have been nice if a “modern” Angus sire group had been added, but that is not possible at this juncture.

  • Is this paper outstanding in its discipline? (For example, would you like to see this work presented in a seminar at your hospital or university? Do you feel these results need to be incorporated in your next general lecture on the subject?) If yes, what makes it outstanding? If not, why not?

    From the perspective of adding to the scientific literature for beef cattle breeding and genetics, the manuscript is outstanding and worthy of presentation at a scientific meeting within the discipline.  The work with multigenerational sires within the Angus breed is unique as is the work with the “modern” sires of the Charolais breed. The manuscript should be referenced in subsequent scientific literature dealing with this subject matter.

  • Other Comments:

    Page 3


    The electronic citations should appear in the literature cited in the proper form for an electronic reference.

    Charolais and Angus sired (calves, animals, etc.) should read Charolais-sired and Angus-sired, respectively.

    Species names should be italicized and the T should be lower case.

    "Dams had ..." should be changed to "Dams were ..." or "Dams had been ...".

    Using Charolais bulls as cleanup bulls introduce bias in terms of weaning age, i.e., Charolais calves were younger.  If you used BIF adjustments or covariate adjustment on data it should be okay.

    What specifically was the suitable harvest weight?


    Page 4

    Were weaning and preweaning data subjected to a BIF adjustements?  If so, this should be stated.  If they weren’t adjusted to BIF standards, there should be a covariate of weaning age for weaning weight at the very least.

    “…calf to carcass program…” should read “…calf-to-carcass program…”.

    “…mixed model procedure of SAS…” should be accompanied by a citation specific to SAS and not as referenced in another article.

    “Random effects…” should read “Dependent variables…”.  Random effects in this model should include sire within breed type. 

    For some traits there was perhaps a covariate fit in the model, please indicate if this is so.

    Actually, it is the PDIFF function of the LSMEANS statement in PROC MIXED that was used for means separation.  This should be a “protected” test, i.e., there should be an overall significant effect of sire breed indicated by the F-test for PDIFF to be used.  With only two levels of sire breed, the F-test should be sufficient for separating the lsmeans.  No PDIFF is necessary and means were separated by the F-test, not the LSMEANS function.  The statistical analyses section should be reworked in this manuscript.

    The probability levels for significance should be stated as follows:  (P< 0.05) wherein “p” is both capitalized and italicized. 

    The sentence “When analyzing the trait birth weight …” should simply and more straightforwardly read “Charolais-sired calves were heavier (P< 0.05) at birth than Angus-sired calves (Table 1).”.  There is no need to state the probability level and whether it is significant or not.  The results section should be re-written with these concepts imposed.

    The authors are encouraged to re-think the use of figures in the manuscript.  A table with means and standard errors for each trait should be more efficient in presenting the data.

    Where are the means for the sex effect and the breed type X sex interaction?  Rather than use the term sex, calf gender would be preferred.
    Were the heavier weaning weights of the Angus-sired calves heavier because they were older?  Please indicate if these were BIF adjusted weights or if a covariate of age was used in the analyses.  Your rationale of stating that the Angus sires were more paternal is suspect.

    “…reported an correlation…” should read “…reported a correlation…”.

    Page 5

    The authors may want to rethink their conclusions in light of a reanalysis of the data incorporating some means of equalizing calf age.  Whether it will have an effect on carcass traits per se, may be a bit sketchy, but should be explored.

  • Competing interests:
  • Invited by the author to review this article? :
  • Have you previously published on this or a similar topic?:
  • References:

    Wyatt et al. 1997. Performance of Angus and Brangus cow-calf pairs grazing Alicia bermudagrass and common bermudagrass-dallisgrass pastures. J. Anim. Sci. 75: 1926-1933. Wyatt et al. 2013. Pre- and postweaning calf performances in crossbred cattle from Hereford, Braford, and Bonsmara sires and Angus and Brangus dams. Prof. Anim. Sci. 29: 621-631. Wyatt et al. 2013. Feedlot performance, carcass merit, and meat tenderness in crossbred cattle from Hereford, Braford, and Bonsmara sires and Angus and Brangus dams. Prof. Anim. Sci. 29: 632-644. Wyatt et al. 2014. Growth and reproductive performances in F1 crossbred heifers from Hereford, Braford, and Bonsmara sires and Angus and Brangus dams. Prof. Anim. Sci. 30: 342-353.

  • Experience and credentials in the specific area of science:

    I received my BS degree in Agricultural Science in 1975 from the University of Tennessee at Martin. I receivedan MS degree in 1978 and a PhDdegree in 1981 in Animal Sciences from Virginia Polytechnic Institute and State University. I am a full professor of Animal Science in a major land grant university (Louisiana State University Agricultural Center) with 32 years of research experience. I have conducted and published research in beef production management and in animal breeding and genetics.

  • How to cite:  Wyatt W .Review on A Quantitative Comparison of Growth and Carcass Traits from Crossbred Calves Sired by a Modern Phenotype Paternal Breed Versus Calves Sired by a Multi-Generational Maternal Breed [Review of the article 'A Quantitative Comparison of Growth and Carcass Traits from Crossbred Calves Sired by a Modern Phenotype Paternal Breed Versus Calves Sired by a Multi-Generational Maternal Breed ' by Garcia M].WebmedCentral 2014;5(8):WMCRW003094
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