# Letter to the Editor: Response to comment on Zened et al. (2024)

Asma Zened

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## To cite this version:

Asma Zened. Letter to the Editor: Response to comment on Zened et al. (2024). Journal of Dairy Science, 2024, 107 (12), pp.10049. 10.3168/jds.2024-25029. hal-04872659

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**Letter to the Editor: Response to comment on Zened et al. (2024)**

**Asma Zened* ◎**

UMR INRAE GenPhySE (Genetics, Physiology and Breeding Systems), Université de Toulouse, INRAE, ENVT, 31326 Castanet-Tolosan, France

We understand the concerns of the reviewers, but our goal was to evaluate the effects of milk replacer fed once or twice daily (a practice used by some farmers) on ruminal metabolites and microbiota in calves.

The animals were closely monitored, and special attention was given to ensure the smooth running of the trial. From a zootechnical point of view and with the number of animals we used (small but sufficient to evaluate the effects of this practice on the microbiota and metabolome), we did not observe any adverse effects (e.g., no weight loss, no diarrhea, and no mortality).

We fully agree with the reviewers that more work needs to be done to assess the health and well-being of calves under these conditions, by experts in these fields.

We have also followed the editor's recommendations. Between the journal preproof and final article, we added a sentence in the Materials and Methods section that specifies the experimental conditions, as follows (Zened et al., 2024):

This work is a companion study to that of Julien et al. (2015) analyzing samples collected from their Holstein calves. This study was conducted at the BORRET experimental farm (INP-ENSAT, Toulouse, France), in accordance with the Guidelines for animal research. At the time of conducting the

study, the experimental farm did not have an institutional animal care and use committee (IACUC) or equivalent but all research animal activity was performed in compliance with federal, state, and local laws of the French Ministry of Agriculture for all animal housing and handling procedures (Anonymous, 1988).

On the other hand, in the ARRIVE Guidelines 2.0 author checklist, we stated that “The study was conducted in 2012, there was no mandatory review by an ethics committee or equivalent approving the use of animals. As such, we were compliant with the guidelines for animal research of the French Ministry of Agriculture.”

**REFERENCES**

Zened, A., C. Julien, L. Cauquil, G. Pascal, C. Canlet, M. Tremblay-Franco, D. Ali-Haimoud-Lekhal, F. Enjalbert, C. Bayourthe, and S. Combes. 2024. Milk replacer feeding once or twice a day did not change the ruminal metabolomic profile and the microbial diversity of dairy calves from birth to weaning. J. Dairy Sci. 107:5574–5586. https://doi.org/10.3168/jds.2023-24327.

**ORCIDS**

Asma Zened ◎ https://orcid.org/0000-0002-0331-940X

Received April 10, 2024.

Accepted July 23, 2024.

*Corresponding author: asma.zened@purpan.fr

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes.