Relationship between Temperate Grass Sward Characteristics and the Grazing Behavior of Dairy Heifers
Round 1
Reviewer 1 Report
Dear Authors
Many thanks to the authors for their responses and improvements to the manuscript. The manuscript is better now. However, based on the results presented in the supplemental table (S2), the study has no solid base to compare the grass species and to take appropriate and solid conclusions.
- Grasses were at maturity stage V3 to V4 (leaf stage). I understand the V3 and V4 stages, however, you don't present a value to prove that all species were in a similar stage, which in my view is complicated to have this value, mainly for all grass species at the same time to carry out field measurements.
- Throughout the manuscript, including in the hypothesis, the authors use the sward structure as the main factor that affects animal behaviour (e.g. lines 62-63; “sward structure features such as bulk density, surface height, leaf length, and herbage mass had greater influence on fine-scale grazing behavior”), but the base to compare the grasses was the stage of maturity, which can be considered a structural characteristic of sward, but complicated to measure. So, in my opinion, this management used to compare the grasses makes no sense, and I believe that the conclusions of the article cannot be based on data that are difficult to measure (V3/V4) and that are not presented in the article. Also, the authors could use the structural characteristics as the height, but as the height of the grasses was different (table S2), this also could not be used to compare the grasses. The sward structure of the species was quite different, it is logical that the behavior of the animals will be affected by this. So, my question is, are the animals' responses related to grass species or sward structure? Unfortunately, this is not possible to know with this study. To have reliable comparisons, grasses should have similar structures, as sward structure affects animal behavior.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This study was determine how the sward characteristics of four diverse, erect-growing temperate types of grass influenced the grazing behavior of dairy heifers at the pasture scale.
The writing of the article has been improved. The authors improve the international terminology for grasslands and animals. Comments on style and suggested wording were made.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 3 Report
The manuscript is well written, had some novel components, and presented interesting findings. I recommend acceptance after addressing some minor edits and points of clarification.
Line 88-89. Measurement units should be reported for each variable in Figure 1.
Line 98. Specify the measurement depth.
Line 143. Specify whether the leaf fraction consisted of blade and sheath or whether the stem fraction contained the sheath considering dry material was separated.
Line 231. Insert space in "was frequently".
Line 234. Insert space before "but".
Line 244. Place comma after the second parentheses.
Line 357-361. If number of bites was negatively correlated with sward height and herbage mass, why cite the studies indicating "adjusting bite depths to selectively graze only the upper strata of taller swards"? Wouldn't the heifers need more bites if grazing only leaf tips to maintain herbage dry matter intake, which contrasts with the finding of less bites with taller swards (i.e., the negative number of bites and sward height correlation)?
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Reviewer 4 Report
The manuscript is a well-designed research paper with clear objectives, well developed and well written.
Some minor comments on the text:
In the manuscript the term "cool-season grasses" and "temperate grass species" are used interchangeably. I believe that the second alternative, which is better known internationally, should be used.
Line 231: wasfrequently. Correct.
Line 145: The formula used and the R2 for the transformation of height to herbage mass should be mentioned. Line 312- and 148. "pregraze herbage allowance was set at approximately twice the expected herbage DMI". Please indicate whether the herbage allowance offered corresponds to a measurement at ground level.
Author Response
Please see the attachment.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
Dear authors,
I really appreciate your work, grazing experiments are complex and it is difficult to control everything, for this reason, there are few researchers working on this topic. However, even though you tried to control the variables as much as possible, in my view the main one was not controlled, which is the structure of the sward. If you had made the evaluations in different grasses with the same height, for example, you would not have this problem, because in that case, you would have a base variable (height). I work with this type of experiment and I can confirm that it is possible to program the evaluations when the height of a certain grass is at the correct height. Sorry, but unfortunately in my humble opinion, the conclusion of the article cannot be supported by the results. This is my final opinion.
Author Response
Dear Reviewer,
We acknowledge your valid concern. Grazing research is extremely challenging given all intrinsic and extrinsic variables, many of which cannot be controlled. Sward height can be confounded with grass species in this study. The grass species in this study were chosen intentionally due to differences in sward structure. For this reason, not all confounding variables could be controlled.
Based on those concerns, we amended the concluding statement in the abstract and also amended the conclusions section to recognize this shortcoming of the research and how it might be addressed in future research to continue gaining knowledge in these dynamic grazing systems.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
Dear authors,
Congratulations for your work, please see my comments and suggestions in the attached document.
Kind regards.
Comments for author File: 
Comments.pdf
Reviewer 2 Report
This study was determine how the sward characteristics of four diverse, erect-growing temperate types of grass influenced the grazing behavior of dairy heifers at the pasture scale. They should improve the style and format of the tables for example Table 1: Aline to center QGR AND RCG.Table 2 and Table 5. Line 182-184: delete Line 243: cite according to the rules of the journal Line 327: cite according to the rules of the journal Line 352: Is it necessary to cite a previous work? Line 355-356: Reconsider deletion of this paragraphReviewer 3 Report
In the introduction must include the effect of species and season on ingestive behavior ;
Great most of the bibliographic references are old;
Short sampling periods for adequate evaluation of the effects of treatments;;
Small number of variables for a scientific article.
Reviewer 4 Report
The effects of pasture structure on the ingestive behavior of ruminants are known in the literature. In addition, a lot of information in the material and methods is confusing, such as the formation of groups of animals (lines 99 and 121) and the subdivision of paddocks (lines 110 to 113). The authors should also explain why they used a significance level of 10% (line 179) to compare the means when it is common to use 5% probability. When presenting the results, the authors often mention differences that do not exist, considering the LSD presented in the tables. An example can be seen in lines 186 and 187. The authors report that the rumination time was lowest in reed canarygrass, however by the reported LSD (47) in table 1, did not differ from the orchardgrass. This is repeated in the description of the other results so that the discussion and conclusions of the article are impaired.
