Pointing Out Some Issues Regarding Reproduction Management in Murciano-Granadina Goats

Round 1

Reviewer 1 Report

1. The number of goats used in the experiment does not coincide between summary and method section: 74 inseminated goats are cited in the 20 weeks of lactation, and in the method 37 inseminated goats, (15 and 25 goats, respectively) remained without treatment, as control) ??. There is no coincidence.
2. There is confusion in the number of samples analyzed in the experiment. Authors must put in parenthesis which sample refers, how many pregnant and non-pregnant goats.
3. The tables of the results are repetitive, for example, the results of table 3 do not need to be cited again. Authors must correct this section.
4. The discussion authors repeat the results Lines 324 to 330. There is no order of the discussion, I suggest dividing the discussion section into sections and doing a better physiological discussion of the progesterone differences with 4 born kids.

Author Response

Manuscript ID: animals-1227818

Title: Pointing out some Issues regarding Reproduction Management in

Murciano-Granadina Goats

Authors: Nemesio Fernández *, M. Carmen Beltrán, Gema Romero, M. Amparo Roca, Martín Rodríguez, Sebastián Balasch

Answer to reviewer one.-

Authors: we have observed that the lines you refer to, in your review, do not correspond exactly to those of the manuscript submitted by the authors or to those of the manuscript that Animals asks us to use. We hope that our answers meet your specifications.

On the other hand, some of the explanatory comments that are proposed in this response, at the request of this reviewer, have not been included in the manuscript, as other reviewers believe that the Discussion section is excessively long or because we consider them to be of a general nature.

1. The number of goats used in the experiment does not coincide between summary and method section: 74 inseminated goats are cited in the 20 weeks of lactation, and in the method 37 inseminated goats, (15 and 25 goats, respectively) remained without treatment, as control) ??. There is no coincidence.

Authors: The number of animals used in this experiment has been eliminated from the "single summary" (SS) section at the suggestion of one of the reviewers.

In the initial version of the manuscript, it was specified, in section SS, that a total of 114 goats had been used, of which 74 had been inseminated and the rest remained non-inseminated. On the other hand, in the "Materials and methods" section it was more specific, since 114 total goats were indicated, 37 goats from each university inseminated (74), and 15 and 25 without insemination (respectively), so the numbers do coincide.

In order to facilitate reading, the non-inseminated goats are more clearly specified for each university in the revised manuscript.

2. There is confusion in the number of samples analyzed in the experiment. Authors must put in parenthesis which sample refers, how many pregnant and non-pregnant goats.

Authors: On the one hand, it must be understood that the number of samples used in the different analyses may be different. It also occurs that, for example, between figure 3 and 1 and 2 the number of samples does not coincide exactly (793 vs 786), because some milk samples for progesterone analysis were spoiled. Or in Figure 4, the number of non-pregnant goats is 22 instead of 38, because some of them did not present a maximum progesterone value.

On the other hand, you are right and the number of samples in Figures 3, 4, 5, 6, 7 and 8 has been clarified.

On the other hand, a comment about the fertility obtained can be found in the second paragraph of the Discussion section.

3. The tables of the results are repetitive, for example, the results of table 3 do not need to be cited again. Authors must correct this section.

Authors: The "Results" section has been revised and the contents that are considered not to contribute information to that presented in tables and figures have been eliminated.

4. The discussion authors repeat the results Lines 324 to 330. There is no order of the discussion, I suggest dividing the discussion section into sections and doing a better physiological discussion of the progesterone differences with 4 born kids.

Authors: We believe that a certain reminder of the results, if it is not excessive, facilitates the reader's understanding, because it allows a direct comparison with other authors without the need to remember or consult the results section again.

On the other hand, the discussion section has been reorganised and new explanatory comments have been added for certain results, so we do not consider it necessary to establish subsections.

Author Response File: Author Response.pdf

Reviewer 2 Report

Author Response

Manuscript ID: animals-1227818

Title: Pointing out some Issues regarding Reproduction Management in

Murciano-Granadina Goats

Authors: Nemesio Fernández *, M. Carmen Beltrán, Gema Romero, M. Amparo Roca, Martín Rodríguez, Sebastián Balasch

Answer to reviewer two.-

Authors: Some of the explanatory comments that are proposed in this response, at the request of this reviewer, have not been included in the manuscript, because we consider them to be of a general nature.

The article describes an interesting but very well-known issue.

Please indicate what is an innovation in the authors' research.

Authors: On one hand, our group has the laboratory to which the milk samples from the dairy industries in Valencia area (Spain) are sent for analysis and, so, establishes the bases that affect the price to be paid to the farmer. We also receive milk samples from the dairy controls of the farms undergoing genetic improvement. We consider that, in addition to referring to the system and the physical-chemical and sanitary quality of the milk samples received, it would be very convenient to also send information on other parameters (reproductive, sanitary, ...) that help the farmers to better manage their herds.

On the other hand, having an idea of what maximum level of milk production does not significantly affect fertility at mating can also help the farmer to better manage the herd.

Finally, it is increasingly difficult to dry the animals off two months before parturition, as they are increasingly productive and, therefore, the application of drying treatments is more common; so knowing the stage for the best application of such treatments is also desirable.

It is not known, at least in this breed, that this type of information is available at this time.

The publication is well written, the discussion is interesting, but too long.

Authors: You are right. The reason that the discussion is so extensive is because many aspects of goat reproduction are addressed and an attempt is made to give a coherent explanation to each of them.

The cited literature is numerous, but very old.

Authors: An extensive bibliographic review was carried out and, indeed, some references are from papers published many years ago, but no more current ones have been found to support or compare our results in some cases. On the other hand, you can also find references from 2019, 2020 or even 2021, which supports the extensive review carried out.

It would be worthwhile to describe an important factor in the discussion, which is fat

Authors: You are right, since progesterone levels in milk are, as referred to in the introduction section, linked to fat. However, more in-depth research into this line of explanation would require a more exhaustive level of fat components than that pursued in the objectives of this manuscript.

Author Response File: Author Response.pdf

Reviewer 3 Report

General Comments

It was an interesting study from the “on field” practitioner sight. But some results should be discussed more detailed with possible explanations.

To be specific:

Simple Summary

I found the simple summary a little extensive, so I propose the authors to cut, if possible, many details (i.e., numbers, etc.) and to focus on the highlights of their interesting study.

Abstract

Line 41: … beyond the days close to heat …. Could it be possible to rephrase the sentence?

Your conclusions should be presented in a clearer manner.

Introduction

Line 64: You mentioned that high progesterone levels from 22-26 days post breeding correspond to pregnant goats. At the same time, you mentioned that the progesterone levels increase from day 4-12 at a cyclic doe. So, from day 24-26 the progesterone level will increase in both cases. Please clarify.

Line 70: It will be better if you add a reference here. The connection with the next sentence is not suitable. Please, rephrase.

Line 74: Suddenly, you change the topic of the paragraph without a proper introduction.

Line 76: A highly milk producing breed is milked once per day???

Finally, you do not present clearly the aim of the study at the end of Introduction section.

Materials and Methods

Line 104: Insemination at 20 weeks of lactation (i.e. 5 months) plus 5 months of gestation equal 10 months lactation period. Is it correct? Why only ten months and not 12 months/1 year? Please explain.

Line 106: Why goats in middle lactation were milked only once per day? What about mastitis cases (they change milk components) since some animals derived 3,250 ml/day?

Line 124-126: To tell you the truth, I do not understand the definition of “the main components”, in combination with the following Figures. Could you describe better the main components? Why only three main components and not four or five? Please, add this explanation in the results section.

Results

The main components and their discrimination should be done.

Line 174: Suddenly, you insert a new definition “basal progesterone”. Please explain.

Figure 3: Could you, please, indicate somehow the statistical differences on the figure?

Line 204: Please, replace Table with Figure.

Please, indicate on all figures the statistical differences in order to help the better understanding of the figures.

Figure 7: You pointed only 4 time points while in the rest figures 6 time points. Please clarify.

Line 237: …there were significant differences between non-pregnant goats… These animals are not indicated on the Figure.

Discussion

Line 256: You recorded contrast of concentrations between lactose and SCC. Could you suggest an explanation? It this connected with the fact that many animals produced significant milk quantity and at the same time milked once?

You mentioned that when progesterone increases in milk samples, milk fat drops. At the same time, progesterone is a lipophilic substance. So I would expect, more fat more progesterone. Please clarify.

Line 259: I would expect that during oestrus (low progesterone) the milk components would be low (due to hyper motility) and not the opposite. You have a different result, so could you give us a possible explanation.

Line 268: Give some possible explanations.

Author Response

Manuscript ID: animals-1227818

Title: Pointing out some Issues regarding Reproduction Management in

Murciano-Granadina Goats

Authors: Nemesio Fernández *, M. Carmen Beltrán, Gema Romero, M. Amparo Roca, Martín Rodríguez, Sebastián Balasch

Answer to reviewer three.-

General Comments

It was an interesting study from the "on field" practitioner sight. But some results should be discussed more detailed with possible explanations.

Authors: OK

To be specific:

Authors: we have observed that the lines you refer to, in your review, do not correspond exactly to those of the manuscript submitted by the authors or to those of the manuscript that Animals asks us to use. We hope that our answers meet your specifications.

On the other hand, some of the explanatory comments that are proposed in this response, at the request of this reviewer, have not been included in the manuscript because other reviewers believe that the Discussion section is excessively long or because we consider them to be of a general nature.

Simple Summary

I found the simple summary a little extensive, so I propose the authors to cut, if possible, many details (i.e., numbers, etc.) and to focus on the highlights of their interesting study.

Authors: OK, the SS has been shortened.

Abstract

Line 41: … beyond the days close to heat …. Could it be possible to rephrase the sentence?

Authors: OK, the sentence has been reworded.

Your conclusions should be presented in a clearer manner.

Authors: OK, the conclusions have also been rephrased.

Introduction

Line 64: You mentioned that high progesterone levels from 22-26 days post breeding correspond to pregnant goats. At the same time, you mentioned that the progesterone levels increase from day 4-12 at a cyclic doe. So, from day 24-26 the progesterone level will increase in both cases. Please clarify.

Authors: In our opinion there is no contradiction between the two sentences. The sexual cycle of goats lasts an average of 21 days. During days 22-26 after the mating of the goats, those that are pregnant continue with an elevated level of progesterone due to the existing corpus luteum, while the cyclic goats will be

increasing their progesterone levels without having yet reached their maximum level.

Line 70: It will be better if you add a reference here. The connection with the next sentence is not suitable. Please, rephrase.

Authors: OK, a new reference has been entered. The following sentence refers to one of the objectives of this experiment and is based on all the previous content of the introduction, not just on the previous sentence.

Line 74: Suddenly, you change the topic of the paragraph without a proper introduction.

Authors: OK, a new sentence has been added at the beginning of the introduction that gives the sense of the two objectives of the experiment.

Line 76: A highly milk producing breed is milked once per day???

The average milk production of the goats used in this experiment is between 400-600 l per lactation and they are milked once a day. In most cases, it is not desirable to increase the output much more, as it would lead to two milkings per day, as occurs in the Saanen or Alpine breeds, for example.

Finally, you do not present clearly the aim of the study at the end of Introduction section.

Authors: You are right. A new sentence has been added at the end of the Introduction paragraph.

Materials and Methods

Line 104: Insemination at 20 weeks of lactation (i.e. 5 months) plus 5 months of gestation equal 10 months lactation period. Is it correct? Why only ten months and not 12 months/1 year? Please explain.

Authors: It is correct. Both herds of goats (UPV and UMH) usually have a 12-month interval between successive kiddings, consisting of 10 months of lactation and two months of dry period. As you know, it is necessary to leave a period without milk production of about two months before parturition to allow the physical and physiological recovery of the animal.

Line 106: Why goats in middle lactation were milked only once per day? What about mastitis cases (they change milk components) since some animals derived 3,250 ml/day?

Authors: During the entire lactation period the goats were milked only once a day, as is usual in this breed, except in herds where milk production is greater than 600 litres. This does not usually lead to major mastitis problems (at least in our herd), although it does cause udder sagging in the case of some animals. In any case, the goats that were taken into account for the results of this experiment were all goats without clinical mastitis.

Line 124-126: To tell you the truth, I do not understand the definition of "the main components", in combination with the following Figures. Could you

describe better the main components? Why only three main components and not four or five? Please, add this explanation in the results section.

Authors: The purpose of main components analysis is to determine a reduced number of new variables that can be used to account for the variation in all the original variables. These new variables are given by a linear combination of the all original variables.

The interpretation in each component is marked by the value of the coefficient associated with each original variable. In Figures 1 and 2, these coefficients are determined by the coordinate in each of the three axes shown in said figures. The new variables are ordered according to the total variability that each one explains, reaching a point where the contribution of one of them and the successive ones is very scarce and they are not taken into account (for this reason, in the manuscript only the 3 first main components appear, and not four or five).

We sincerely consider that these explanations should not be included in the manuscript.

Results

The main components and their discrimination should be done.

Authors: It is not a discrimination, but an explanation of the total variability by each of the 3 main components. Between them, they contribute 74% of the total variability of the variables studied.

Line 174: Suddenly, you insert a new definition "basal progesterone". Please explain.

Authors: You are right. Sometimes the writer considers some equivalent terms but, indeed, they can cause confusion in the reader. We have changed "basal" to "minimum" and "luteal" to "maximum".

Figure 3: Could you, please, indicate somehow the statistical differences on the figure?

Authors: An explanation has been introduced in M and M (at the end of sub-section 2.4) that we think makes inclusion of the statistical differences in the figures unnecessary.

Line 204: Please, replace Table with Figure.

Authors: OK.

Please, indicate on all figures the statistical differences in order to help the better understanding of the figures.

Authors: An explanation has been introduced in M and M (at the end of sub-section 2.4) that we think makes inclusion of the statistical differences in the figures unnecessary.

Figure 7: You pointed only 4 time points while in the rest figures 6 time points. Please clarify.

Authors: Figure 7 shows the mean progesterone value, between days +15 and +90 post-mating, for non-pregnant goats or for those pregnant with 1, 2, 3 or 4

foetuses. Something similar happens with figure 8 (in this case for actual milk). However, the previous figures study the record-to-record evolution of actual milk, progesterone, ... for the groups of pregnant or non-pregnant goats. Therefore, the objective of both types of curves is different.

Line 237: …there were significant differences between non-pregnant goats… These animals are not indicated on the Figure.

Authors: OK. This has now been corrected.

Discussion

Line 256: You recorded contrast of concentrations between lactose and SCC. Could you suggest an explanation? It this connected with the fact that many animals produced significant milk quantity and at the same time milked once?

Authors: The main components study was carried out, among other things, as a security measure that our data are consistent, as in some cases they are contradictory with the findings of other authors.

In a healthy goat, lactose is the most important component of milk for the osmosis processes between it and the blood. SCC values in milk higher than what is considered "threshold" indicate that the health status of the udder may have a degradation to a greater or lesser extent. This degradation of the mammary gland leads to the "tight junctions" between the milk-secreting cells becoming more permeable to other solutes from the blood, so that when the osmotic balance between both fluids is reached there is a lower amount of lactose than in a healthy goat.

You mentioned that when progesterone increases in milk samples, milk fat drops. At the same time, progesterone is a lipophilic substance. So I would expect, more fat more progesterone. Please clarify.

Authors: In the Introduction section, the usual higher concentration of progesterone in milk than in blood is justified due, among other possible causes, to its affinity for fatty esters. On the other hand, observing Figure 2 of the results of this experiment, it can be seen that there is a "tendency" that by increasing progesterone levels in the milk, the levels of the rest of the parameters studied are reduced, and a non-negligible number of samples (786) was used. We all know that biological systems tend to have operational thresholds, above or below which the results stabilise. The breed of goats used in this experiment produces much less milk (400-600 l per lactation) than, for example, Saanen or Alpina (900-1000 l per lactation), although with higher fat percentages. We do not know results in this regard, but it could occur that, as of a certain level of fat, the response in terms of progesterone concentration is irrelevant.

Line 259: I would expect that during oestrus (low progesterone) the milk components would be low (due to hyper motility) and not the opposite. You have a different result, so could you give us a possible explanation.

Authors: You are right; in fact, this is underlined in the discussion section, but the results are very clear. The truth is that we were surprised that, for example during the autumn, the number of goats with high levels of progesterone in milk was low. As a possible explanation we could think of an interference of the lactation period with the reproductive one. For example, that in the middle of

autumn the UPV goats were near the peak of lactation and, therefore, in a state of lower body condition that reduced their coming into heat; the opposite occurred in winter and spring when the goats were in a more advanced stage of lactation and, presumably, in better body condition

Line 268: Give some possible explanations.

Authors: OK, please see the manuscript.

The authors wish to thank you for your contributions to the manuscript.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

manuscript is improved

Author Response

Dear reviewer

All the suggestions made by you have been executed. On the one hand, the manuscript has been reviewed by a native English language specialist. On the other hand, the modifications made to the text, throughout the revision process, are reflected in red type for their better location

Sincerely

Nemesio Fernández

Corresponding author

Author Response File: Author Response.pdf

Reviewer 3 Report

Thanks for your answers to my comments.

I will insist on two things.

1. Line 104: Insemination at 20 weeks of lactation (i.e. 5 months) plus 5 months of gestation equal 10 months lactation period. Is it correct? Why only ten months and not 12 months/1 year? Please explain.

Authors: It is correct. Both herds of goats (UPV and UMH) usually have a 12-month interval between successive kiddings, consisting of 10 months of lactation and two months of dry period. As you know, it is necessary to leave a period without milk production of about two months before parturition to allow the physical and physiological recovery of the animal.

Ok I agree with you but in this case, you speak for a 10 month interval (not a 12 month) between kiddings including a 2 months dry period. Please clarify.

2. Line 256: You recorded contrast of concentrations between lactose and SCC. Could you suggest an explanation? It this connected with the fact that many animals produced significant milk quantity and at the same time milked once?

Authors: The main components study was carried out, among other things, as a security measure that our data are consistent, as in some cases they are contradictory with the findings of other authors. In a healthy goat, lactose is the most important component of milk for the osmosis processes between it and the blood. SCC values in milk higher than what is considered "threshold" indicate that the health status of the udder may have a degradation to a greater or lesser extent. This degradation of the mammary gland leads to the "tight junctions" between the milk-secreting cells becoming more permeable to other solutes from the blood, so that when the osmotic balance between both fluids is reached there is a lower amount of lactose than in a healthy goat.

Exactly. But both the lactose drop (increase of ions and electrical conductivity) and SCC increase may indicate clinical or subclinical mastitis. So it is significant to mention that after clinical examination there was no clinical or subclinical mastitis. 

Thanks in advance!

Author Response

Dear reviewer

All the suggestions made by you have been executed. On the one hand, the manuscript has been reviewed by a native English language specialist. On the other hand, the modifications made to the text, throughout the revision process, are reflected in red type for their better location

Sincerely

Nemesio Fernández

Corresponding author

Author Response File: Author Response.pdf