The Effect of Supplemental Lighting during the Late Gestation Period on Post-Partum Mechanical Properties of Mare and Foal Guard Hair

Round 1

Reviewer 1 Report

Thank you for sending this manuscript. It is an interesting study on the effect of light supplementation in mares on the hair of their foals. The study is quite interesting, and its results could be used in the horse breeding history. 

A few remarks:

I think the introduction is quite long, a summary of the findings could be more interesting for the reader, and some of the information could be moved to the discussion section.

Line 69: please delete (p. 117)

Line 72: please delete (pp. 415-419)

Line 110: please change "proven" with "proved"

Author Response

Response to Reviewer 1:

The authors gratefully thank the reviewer for his/her comments and suggestions. The answers are pasted after the comments. They request that the responses be accepted.

Thank you for sending this manuscript. It is an interesting study on the effect of light supplementation in mares on the hair of their foals. The study is quite interesting, and its results could be used in the horse breeding history.

A few remarks:

I think the introduction is quite long, a summary of the findings could be more interesting for the reader, and some of the information could be moved to the discussion section.

The introduction has been shortened by four long paragraphs and sentences.

Line 69: please delete (p. 117)

It has done

Line 72: please delete (pp. 415-419)

It has done

Line 110: please change "proven" with "proved"

It has done

Reviewer 2 Report

See attachement

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2:

The authors gratefully thank the reviewer for his/her comments and suggestions. The answers are pasted after the comments. They request that the responses be accepted.

The effect of supplemental lighting during the late gestation 1 period on post-partum mechanical properties of mare and foal 2 guard hair. The paper reports about a study on the effect of a specific light exposure to pregnant mares on physical properties of hair ob marex and foals.

The study is conducted with a sufficient number of animals and the methods for measuring the hair and data processing are adequate.

In gerneral, the data and presentation of data are convincing. I like to give some remarks.

1. One hair sample per animals was obtained at a defined timing related to parturition. The authors state that the condition at the beginning has been more or less identical for control and treated individual. This is not precisely recorded but likely worthwhile to be discussed. I recommend to to give some more space on the base for the mentioned statement or to take this aspect into the discussion.

Thanks for this comment. The circumstances of the start of the trial were additionally included in the Material and method chapter.

“Before the start of the experiment and the separation of the test groups, the pregnant mares were kept together in the same place under the same conditions as the later control group was.”

2. If data on temperature (season before and during the experimental period are available, it would be a benefit to have those. If not, please consider a possible impact of temperature on hair growth in the discussion.

Thank you very much for the valuable addition. We also agree with the importance of temperature. We refer to DeBoer et al. (2023), in which the hair of blanketed and non-blanketed horses was examined. In our processing, the taps were in the same location and temperature conditions. Based on your suggestion, we added the fact of this to the Material and method chapter. Therefore, we did not consider the separate effect of temperature.

“The individuals of the groups were housed in the same conditions, so they were equally affected by the seasonal changes in temperature.”

3. The need of Tab. 3 is not clear to me. I recommend to consider to leave out this table.

The structure of Table 3 is the same as the table showing the results of the other tested properties. In our opinion, hair length (in mm) is an important property measured by many, so its presentation provides an opportunity for comparison with the results of these authors. Thank you for your comment, because based on this, we have replaced the word fibre with the word hair.

4. I recommend to give more details (e.g. a figure) related to the relationship between body weight and hair characteristics. This is an interstiming but underestimated aspect. It is usual to use average hair data for horses with 100 - 1000 kg body mass. The authors comments may indicate that it is worthwhile to consider an allometric effect.

The fairly uniform and inbred Thoroughbred breed was used in our investigation. The age and live weight of the investigated mares were within narrow limits. In processing, we used a linear model to look at the relationship between weight and hair properties (isometric change). The relative homogeneity of our dataset does not make it possible to evaluate non-linear relationships (allometric effects) in the weight range suggested by the reviewer.

5. The discussion ends by a few words on pelage related aspects like insulation(row 494-497). I think this few lines refer to a major aspect. A change in hair coat against the natural physiological reglement creates an impact on several conditions, e.g. metabolic rate. I recommend to bring mor discussion on this point. The effects of modified day length by artificial light on breeding strategies and - considering this paper - on hair properties is clear. But the idea to use artificial light has mainly an economical background. I would be happy to have some comment what does it mean for the animal.

We agree with this critics of the reviewer. In many cases, physiological processes are directly related to the temperature. Therefore, in the manuscript, we cited a paper of O'Brian et al. (2020), which connects the use of light supplementation in cold winter under indoor keeping and with additional heating.