Assessment of Noninferiority of Delayed Oral Calcium Supplementation on Blood Calcium and Magnesium Concentrations and Rumination Behavior in Dairy Cows

Round 1

Reviewer 1 Report

The article is relevant and is very well written. There are minor considerations, listed below:

1) line 128 - replace the cited reference by its number;

2) lines 136 to 138 - insert in the text that the noninferiority criterion is for calcium concentration.

Author Response

Line 128 - replace the cited reference by its number.

The suggestion of replacing the reference by its number was modified in the text.

Lines 136 to 138 - insert in the text that the non-inferiority criterion is for calcium concentration.

It has been added to the text that the non-inferiority criterion was based on calcium blood concentration.

Reviewer 2 Report

Regarding MS entitled ‘’ Assessment of noninferiority of delayed oral calcium supplementation on blood calcium and magnesium concentrations and rumination behavior in dairy cows’’ the manuscript is interesting, but I still have some comments:

Abstract

Please add p-value for significant findings

A conclusion sentence should be added at the end of the abstract with recommendations to the readers.

Materials and Methods

Please write the DCAD of pre- and postpartum diet.

L73. fed non-limiting amounts of total mixed ration, please explain why? Is this NRC recommendation?

Results

Feed intake and production performance (e.g. milk yield) should be added to be clear for the readers.

Conclusion

The authors repeated the findings. Please be precise and add a conclusion sentence with a recommendation to the readers.

Author Response

• Please add p-value for significant findings

A p-value was added for Mg plasma concentration finding.

• A conclusion sentence should be added at the end of the abstract with recommendations to the readers.

A final sentence was added stating that our results suggest no negative impacts of treatment and that delayed calcium administration could be use as alternative protocol on dairy farms.

• Please write DCAD of pre and postpartum diet.

DCAD value (prepartum) was corrected in the text. A postpartum DCAD can be found on Table 1.

• fed non-limiting amounts of total mixed ration, please explain why? Is this NRC recommendation?

To the authors knowledge, there is no NRC recommendations for non-limiting amount of TMR for dairy cows. Authors provided with, previous literature, the reasons to feed ad libitum dairy cows around parturition.

• Feed intake and production performance (e.g., milk yield) should be added to be clear for the readers.

Milk-yield and dry matter intake were incorporated in the materials and methods, statistical analysis, and results. For milk-yield, the week after calving was analyzed. For DMI, week prior to calve and week after calving was compared between groups.

• The authors repeated the findings. Please be precise and add a conclusion sentence with a recommendation to the readers.

A conclusion sentence was added to the paper stating the authors recommendations.

Reviewer 3 Report

The authors carried out a very interesting study to assess the non-inferiority of calcium treatment within the first 24 hours postpartum compared to the traditional treatment within the first 24 hours after parturition.

I believe that the study could have had more robust results if it had been carried out with a larger number of animals.

Furthermore, for me the most suitable design would be a clinical trial comparing the effectiveness of treatments only in cows diagnosed with clinical hypocalcemia or subclinical hypocalcemia.

Therefore, I would recommend the authors to carry out a new submission with new data in order to have more robust results.

In addition, I would recommend to evaluate milk production and the incidence of other diseases during the postpartum period, including: metritis, endometritis, lameness, mastitis, etc.

Also, if it is possible to measure other variables such as BHB, NEFA, haptoglobin, etc., I believe it would enrich the quality of the study.

Round 2

Reviewer 2 Report

Thank you for the revisions. The manuscript was improved.