Online Monitoring of the Temperature and Relative Humidity of Recycled Bedding for Dairy Cows on Dairy Farms
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsТhe article fermentation-3041573 is devoted to the control of the processing of cow manure into bedding for cows. The article is devoted to current topics, and the novelty lies in a simple system for online monitoring of temperature and relative humidity. The work can be used on dairy farms, this is the positive side of the work. The work confirms the essentially known methods of manure fermentation described in the literature. Materials and methods are well described.
A few notes.
1) Lines 37-40 criticize the use of manure in agriculture. But it is also necessary to bring up the positive aspects, because the use of manure refers to organic farming. By the way, after the high-temperature fermentation described in the article, the resulting litter can be used to house animals, and then the waste litter can be used as fertilizer. In general, the proposed method makes it possible to obtain fermented manure for a variety of uses.
2) Reference 27 does not reflect Van Soest's method.
3) How do the authors see the development of the work? How long can bedding produced using Method A be used and when should it be replaced? What are the markers for the need to replace litter?
4) Figure 6. Provide transcript T.B.C.
5) Figure S3. Error in figure captions.
Author Response
Please see the Marked-up Revised Manuscript and Supporting Informations in the attachment.
Response to Reviewer #1 
Original comment
Тhe article fermentation-3041573 is devoted to the control of the processing of cow manure into bedding for cows. The article is devoted to current topics, and the novelty lies in a simple system for online monitoring of temperature and relative humidity. The work can be used on dairy farms, this is the positive side of the work. The work confirms the essentially known methods of manure fermentation described in the literature. Materials and methods are well described.
A few notes.
Response: We are very appreciate to the reviewer for his/her very positive comments on this manuscript.
Comment 1.1: Lines 37-40 criticize the use of manure in agriculture. But it is also necessary to bring up the positive aspects, because the use of manure refers to organic farming. By the way, after the high-temperature fermentation described in the article, the resulting litter can be used to house animals, and then the waste litter can be used as fertilizer. In general, the proposed method makes it possible to obtain fermented manure for a variety of uses.
Response: Thanks to the reviewer's suggestion. We have redescribed the resource utilization value of cow manure in making fertilizer: One of the most commonly used methods of manure treatment is fertilizing the land. There are abundant N, P and S elements in dairy manure, which can also play a role in increasing soil fertility. However, cow dung is produced in large quantities, and the ability of land to dissolve is limited. Excessive or inappropriate return of manure to the field can cause a number of problems, such as environmental degradation, climate change, resource depletion, acidification and eutrophication potential.
Comment 1.2: Reference 27 does not reflect Van Soest's method.
Response: Thanks to the reviewer, and we have replaced it [Waste Management, 30 (2010) 2448-2460]. The new literature describes Van Soest's method in detail, which is consistent with the method in this manuscript.
Comment 1.3: How do the authors see the development of the work? How long can bedding produced using Method A be used and when should it be replaced? What are the markers for the need to replace litter?
Response: Thanks for the comments. This online monitoring system can better realize the automation of farm production and control. This monitoring method can be used for the potential application of large dairy farms, to optimize the process by designing the fermentation process, and to monitor the daily bedding production process. The above discussion has been added to the Conclusion Section.
As can be seen from the experimental data presented (Figure 6), the Method A can keep the E. coli content low for no less than 5 days, so the recommended replacement time is 3-5 days. We also add to the above discussion in the manuscript: In general, the dairy manure bedding material obtained by the group A method is used for no less than 5 days with dairy cow, so it is recommended to replenish with fresh litter every 3-5 days.
Comment 1.4: Figure 6. Provide transcript T.B.C.
Response: Thanks. The “T. B. C” is an acronym for Total Bacteria Counts, and we have added a description to the diagram.
Comment 1.5: Figure S3. Error in figure captions.
Response: We are very sorry for our careless, and we have corrected it.
Reviewer 2 Report
Comments and Suggestions for AuthorsOn-Line Monitoring of Temperature and Relative Humidity of Recycled Dairy Cow Bedding Applied in Dairy Farms
The authors of this study examined how the distribution of temperature and relative humidity during strip stacking fermentation affects the nutrient content curve, water and ash content, and the retention rate of cellulose, hemicellulose, and lignin. They conducted a systematic investigation using a multi-probe integrated temperature and relative humidity online monitoring system. Further authors have demonstrated that optimal bedding material can be achieved by employing a methodical approach to fermentation and stacking. Authors need to revise the manuscript considering the comments.
Comments
· The temperature curves of -0.05 m and -0.25 m depths were synchronously 201 changed with 0.05 m of ambient temperature, indicating the superficial temperature of 202 manure stacked was significantly affected by the ambient temperature--- any chances that change in temperature alter the microbial population.
· Too much moisture will affect the air permeability, and too little moisture will affect the reproduction of beneficial 268 bacteria ---- Are the moisture values provided for both cases in this instance?
· During fermentation, the nutrients were decreasing for both A and B groups, due to the gradual increase in the number of beneficial strains during the fermentation process which coincides with the number of T. B. C------- Generally which particular strains increased thar are found to be beneficial,
· Because the oxygen and moisture can be diffused by mass transfer, aerobic fermentation dominated in the middle and upper layers. But the oxygen cannot transfer into the deep layer, 315 so anaerobic fermentation dominated----- any chances of formation of short chain or dicarboxylic acids during this phase of fermentation.
· Comparing the difference between the A and B groups of dairy manure fermentation, the rate of nutrient consumption in group A was faster than that in group B, indicating that flipping stack increased mass transfer of water and oxygen, promoting aerobic fermentation---- what was the switch between the A and B group that regulated the aerobic and anaerobic fermentation.
Comments on the Quality of English Languagena
Author Response
Response to Reviewer #3 
Original comment
The authors of this study examined how the distribution of temperature and relative humidity during strip stacking fermentation affects the nutrient content curve, water and ash content, and the retention rate of cellulose, hemicellulose, and lignin. They conducted a systematic investigation using a multi-probe integrated temperature and relative humidity online monitoring system. Further authors have demonstrated that optimal bedding material can be achieved by employing a methodical approach to fermentation and stacking. Authors need to revise the manuscript considering the comments.
Response: We are very appreciate to the reviewer for his/her comments on this manuscript. We have revised the manuscript according to the comments and marked as RED.
Comment 3.1: The temperature curves of -0.05 m and -0.25 m depths were synchronously changed with 0.05 m of ambient temperature, indicating the superficial temperature of manure stacked was significantly affected by the ambient temperature--- any chances that change in temperature alter the microbial population.
Response: Thanks for the question. The temperature at -0.05 m and -0.25 m depths both fluctuate with the environment. However, the lowest temperature at -0.25 m depth could reach to 60 °C during 2nd~7th day. The temperature change during the fermentation experiment is a fluctuation in the high temperature range from 50°C to 75°C. Therefore, Temperature fluctuations in this range do not easily alter microbial populations, and the surviving microbial population is bacteria that are resistant to high temperatures. We have also added the above discussion to the manuscript.
Comment 3.2: Too much moisture will affect the air permeability, and too little moisture will affect the reproduction of beneficial bacteria ---- Are the moisture values provided for both cases in this instance?
Response: Thanks for the question, we have added two references and corresponding references: Too much moisture (>70 %) will limit the air permeability [J. Environ. Eng. 123.3 (1997): 275-281], and too low moisture (<30 %) will affect the reproduction of beneficial bacteria [Animals, 11 (2021) 2890].
Comment 3.3: During fermentation, the nutrients were decreasing for both A and B groups, due to the gradual increase in the number of beneficial strains during the fermentation process which coincides with the number of T. B. C-------Generally which particular strains increased thar are found to be beneficial.
Response: Thanks for the question. There are several beneficial bacteria in cow manure reported, such as Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria [J. Dairy Sci. 106.1 (2023): 257-273.]. These bacteria could degrade the nutrient in cow manure and produce a high-temperature so to kill the eggs of pathogenic bacteria. We have also added the above discussion to the manuscript.
Comment 3.4: Because the oxygen and moisture can be diffused by mass transfer, aerobic fermentation dominated in the middle and upper layers. But the oxygen cannot transfer into the deep layer, so anaerobic fermentation dominated----- any chances of formation of short chain or dicarboxylic acids during this phase of fermentation.
Response: Thanks for the question. During the anaerobic fermentation, short-chain fatty acids and dicarboxylic acids (such as fumaric acid) could be produced [Bioprocess and Biosystems Engineering, 43.4 (2020): 569-591]. These short-chain fatty acids and dicarboxylic acids can provide nutrients to the bacteria and are not conducive to the long-term use of the litter. Therefore, anaerobic fermentation needs to be avoided as much as possible. We have also added the above discussion to the manuscript.
Comment 3.5: Comparing the difference between the A and B groups of dairy manure fermentation, the rate of nutrient consumption in group A was faster than that in group B, indicating that flipping stack increased mass transfer of water and oxygen, promoting aerobic fermentation---- what was the switch between the A and B group that regulated the aerobic and anaerobic fermentation.
Response: Thanks for the question. Flipping the stack is the switch between the A and B group that regulated the aerobic and anaerobic fermentation. In this work, the stack of A group was flipped twice, while B group was not flipped. We have also added the above description to the manuscript.
Reviewer 3 Report
Comments and Suggestions for AuthorsDear Editor and Authors,
thank you for the opportunity to review the interesting manuscript: On-Line Monitoring of Temperature and Relative Humidity of Recycled Dairy Cow Bedding Applied in Dairy Farms. The authors point to the effects of the temporal and spatial distribution of temperature and relative humidity of strip stacking fermentation on the content curve of nutrients, water and ash content, the retention rate of effective bedridden materials of strip stacking fermentation through the online monitoring system. The manuscript has potential for application and meets the requirements for publication in the Fermentation. There are several errors in the text, which I mentioned in the comments:
AIM OF STUDY
The aim of the study is clearly defined sufficiently.
ABSTRACT
Lines 18 - 23: The sentence is too long, I recommend shortening and dividing it.
INTRODUCTION
Lines 47 – 48: After sentence is missing citation. I recommend adding more recent citation:
https://doi.org/10.3390/agriculture11100980
Lines 52 – 53: All bacteria must be correct in italics.
Lines 53 – 54: The number of bacteria in the bedding material was positively correlated with the type and the end of the teat [7]. The cited study (7) aims not to mention the number of bacteria in the bedding material. I recommend replacing it with a more up-to-date one that is focused on the mentioned issue: https://doi.org/10.3390/agriculture10060245
Lines 53 – 59: I recommend adding a more recent citation: https://doi.org/10.3390/vetsci10060386
METHODOLOGY
There is no methodology for taking samples from fermented dairy manure to measure bacteria content. A major shortcoming of the study's methodology is that fecal coliform bacteria and coliform bacteria were not measured.
Lines 149 – 169: All bacteria must be correct in italics.
RESULTS AND DISCUSSION
Correct E. Coli, S. Agalactiae and S. Aureus to italic with correct interpretation in whole text: E. coli, S. aureus, S. agalactiae
Figures 2-6 are very small and hard to read. I recommend moving some of them to the Supplementary materials.
CONCLUSION
The conclusion sums up the results of the study and clearly shows how this type of study can be applied to fermentation management and fermentation process optimization in large-scale dairy farms.
Author Response
Please see the Marked-up Revised Manuscript and Supporting Informations in the attachment.
Response to Reviewer #2 
Original comment
Dear Editor and Authors,
thank you for the opportunity to review the interesting manuscript: On-Line Monitoring of Temperature and Relative Humidity of Recycled Dairy Cow Bedding Applied in Dairy Farms. The authors point to the effects of the temporal and spatial distribution of temperature and relative humidity of strip stacking fermentation on the content curve of nutrients, water and ash content, the retention rate of effective bedridden materials of strip stacking fermentation through the online monitoring system. The manuscript has potential for application and meets the requirements for publication in the Fermentation. There are several errors in the text, which I mentioned in the comments:
Response: We are very appreciate to the reviewer for his/her very positive comments on this manuscript. We thank to the reviewer for pointing out formatting and grammatical errors. We have corrected the issues and errors pointed out one by one.
Comment 2.1: (AIM OF STUDY) The aim of the study is clearly defined sufficiently.
Response: We thank for the positive comment.
Comment 2.2: (ABSTRACT) Lines 18 - 23: The sentence is too long, I recommend shortening and dividing it.
Response: Thanks for the suggestion. We've rewritten it and changed it into three sentences: In this work, a multi-probe integrated temperature and relative humidity online monitoring system was used for fermentation process optimization. The effects of the temporal and spatial distribution of fermentation temperature and relative humidity on the nutrient content curve, moisture and ash content of manure bedding materials were systematically studied. The effect of fermentation process on the retention rate of effective bedridden materials (cellulose, hemicellulose and lignin) was analyzed.
Comment 2.3: (INTRODUCTION) Lines 47 – 48: After sentence is missing citation. I recommend adding more recent citation: https://doi.org/10.3390/agriculture11100980
Response: Thanks for the suggestion. We've added the above reference [Agriculture, 2021. 11(10), 980].
Comment 2.4: Lines 52-53: All bacteria must be correct in italics.
Response: Thanks for pointing it out, and we corrected it.
Comment 2.5: Lines 53-54: The number of bacteria in the bedding material was positively correlated with the type and the end of the teat [7]. The cited study (7) aims not to mention the number of bacteria in the bedding material. I recommend replacing it with a more up-to-date one that is focused on the mentioned issue: https://doi.org/10.3390/agriculture10060245
Response: Thanks for the suggestion, we have made a replacement [Agriculture, 2020. 10(6), 245].
Comment 2.6: Lines 53-59: I recommend adding a more recent citation: https://doi.org/10.3390/vetsci10060386
Response: Thanks for the suggestion. We have added the above reference [Veterinary Sciences, 2023. 10(6), 386].
Comment 2.7: (METHODOLOGY) There is no methodology for taking samples from fermented dairy manure to measure bacteria content. A major shortcoming of the study's methodology is that fecal coliform bacteria and coliform bacteria were not measured.
Response: Thanks for the question. The main pathogens causing mastitis in dairy cows is Escherichia coli. And fecal Escherichia coli is one of the Escherichia coli, so we only explored the number of Escherichia coli in this experiment. We mainly explored the correlation of multiple litter indicators, including the number of pathogenic bacteria, nutrients, moisture, and bed rest rate, and the detailed discussion of bacterial types is not the focus of this paper.
Comment 2.8: Lines 149-169: All bacteria must be correct in italics.
Response: Thanks, and we have corrected it.
Comment 2.9: (RESULTS AND DISCUSSION) Correct E. Coli, S. Agalactiae and S. Aureus to italic with correct interpretation in whole text: E. coli, S. aureus, S. agalactiae
Response: Thanks. We have corrected them.
Comment 2.10: Figures 2-6 are very small and hard to read. I recommend moving some of them to the Supplementary materials.
Response: Thanks for the suggestion, and we've enlarged the font size of the image and some of the figures into Supplementary materials (New Figure S5).
Comment 2.11: (CONCLUSION) The conclusion sums up the results of the study and clearly shows how this type of study can be applied to fermentation management and fermentation process optimization in large-scale dairy farms.
Response: Thanks to the reviewers for his/her meticulous review.
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsManuscript ID- fermentation-3041573
The authors have modified the manuscript according to the comments provided by the reviewer. The study results are interesting in the domain of usage of online monitors to analyze temperature and relative humidity distributions in recycled dairy manure bedding materials.
The article may be considered for publication.
