Periodicity Intensity of the 24 h Circadian Rhythm in Newborn Calves Show Indicators of Herd Welfare

Round 1

Reviewer 1 Report

In this work, the authors recorded overall movements over an 8-week period by means of accelerometers worn around the necks of newborn calves, and calculated from the movement data the 24-hour periodicity corresponding to circadian rhythms. The results show that processing and visualizing movement data in this manner allows observation of external factors affecting herd welfare, while revealing insights that cannot be observed from movement data alone. However, there are some issues should be addressed before it can be considered for publication.

1. The authors mention in the conclusion section that this form of analysis is more sensitive than the current form of analysis, please describe the current form of analysis in the manuscript.

2. Manuscript language suggestions were revised.

3. The errors in the references and texts are listed below, please check and correct them:

(1) The format of the references title is not uniform, please check it carefully. Such as:

[1] Nelson, C.R.; Kang, H. Spurious periodicity in inappropriately detrended time series. Econometrica: Journal of the Econometric Society 1981, pp. 741–751.

[2] Buman, M.; Hu, F.; Newman, E.; Smeaton, A.; Epstein, D. Behavioral Periodicity Detection from 24 h Wrist Accelerometry and Associations with Cardiometabolic Risk and Health-Related Quality of Life. BioMed Research International 2016, 2016. https://doi.org/10.1155/2016/4856506.

(2) Some error in text should be checked:

In abstract, “Our method reveals insights not observable from movement data alone.” should be “our method …”

The authors are strongly suggested to check the similar issues over the references and text.

 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors,

 

while the overall topic of the manuscript is interesting, the reader would befit from some additional information and context – in particular who and how will benefit from the results gained? 

 

I imagine data acquisition here challenging and acknowledge the efforts made. However, in my opinion, the overall study should have been conducted with more scientific rigour.  For example, I assume that when observing the circadian rhythm and arriving to any conclusions, the authors should first consider whether the calves were in contact with humans? How can this contact be described? Were the calves fed at regular times of day? What other external patterns (huma or non-human related) did the calves experience? 

 

Equally important are my concerns regarding the signal processing.  Firstly, exact PSD calculation should be clearly stated – in particular – with how many points the PSD is approximated with (and what is the frequency resolution)? Additionally, why not present and conclude more from the PSD results obtained, since PSD is already calculated? If only 24hour periodicity is of interest, then some other methods should be used – there are many computationally much more efficient ways for estimating the intensity of a particular frequency component’s presence then using PSD. A more thorough literature overview on periodicity extraction would benefit since this is a much studied topic in the signal processing domain. 

 

 

Minor regards are as follows.

 

In Lines 58-59 you state that the device contains a micro-electromechanical system and a 3D accelerometer. From this statement an uneducated reader might assume that the 3D accelerometer itself is not a micro-electromechanical system.

 

In Line 63 you state that the device has 512 Mb of memory. If you meant megabytes then MB is the proper abbreviation since Mb refer to megabits. Memory is usually stated in MB. Moreover, 512 Mb would be too low for purpose reported.

 

Brackets in the SVM equation are obsolete. 

 

In Line 80 the authors should clearly state that the range between 0.5 and 20 Hz refers to the band-pass frequency region of the filter (and not to the filter itself).

 

Labels for graph axes in Figure 3 are much needed. 

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors show that the periodic intensity of circadian rythms in newborn calves is dependent on the herds. However, in my opinion there are few points that can be improved upon.

1. What is the real novelty of the work that is related to sensors or sensor development? The authors claim that a similar work is already performed for humans. Is the novelty only that this is now performed on calves?

2. There is too much explanation about Axivity AX3. One or two statements suffice. There is no need for two entire paragraphs.

3. In Figure 3, the periodictiy intensity in general is closer to 0, which is considered to be weak periodicity according to the authors. Why is it weak? Authors should comment on it.

4. What is the final conclusion after multiple graphs which picked random calf samples? What is the interpretation of the circadian periodicity of an individual calf?

5. Once again, what is the novelty of the sensors used in this manuscript, in general, that guarantees a publication in "Sensors journal"?

 

Best regards

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have addressed all the issues about the questions, and recommendation for publication as it is now.

Reviewer 2 Report

Since all of my concearns have been succesfully addressed, I suggest the manuscript is accepted for publication. 

Reviewer 3 Report

Dear authors,

Thank you for addressing my comments. I find them satisfactory. I wish you all the best with the manuscript.