Milk Properties and Morphological Characteristics of the Donkey Mammary Gland for Development of an Adopted Milking Machine—A Review
Round 1
Reviewer 1 Report
In this study entitled "Milk Properties and Morphological Characteristics of the Donkey Mammary Gland for Development of an Adopted Milking Machine", the Authors describe the main characteristics of milk yield, lactation curve, milk quality, udder morphological traits and the characteristics of milking machine in donkey breed.
Although the Authors produce a considerable amount of informations, the paper has some limitations that affect its publication in this form, which I summarize below:
Line 35: Equus asinus, rewrite in italics.
Line 41-42: Hippocrates (460-370 v. C hr.), rewrite in correct form.
Line 57-60: “The average daily milk yield over the entire lactation season was 1.39±0.66 kg/d and fluctuated between 0.70 and 3.00 kg/d (Tab. 1). However, the daily milk yield in donkeys is influenced by many factors, such as breed, feeding, stage of lactation, lactation number, foaling season, milking procedure and production country [1,18, 20-22].”
The two sentences must be completely reformulated, in the light of the considerations reported by Miraglia, N.; Salimei, E.; Fantuz, F. Equine milk prodcution and valorization of marginal areas-a review. Animals 2020, 10(2), 353. (Reference 86).
See paragraph “3.1. Equine Milk Yield and Management of the Dairy Equine Enterprise.” The core of the dairy equine enterprise is related to the management of dams and foals, and of the milking practice, showing important differences from the conventional dairy species. Firstly, dams and foals live together until weaning, which occurs at 7 months (for foals) or later; dams won’t start to be milked before 20 d from foaling [10,68]. Secondly, since the equine mammary gland is characterized by small volume, and milk is mainly alveolar [69], milk harvesting can be carried out many times per day. In the Steppes of Central Asia, mares are milked 4–5 times per day [70], while in more intensive dairy farms located in Europe, mares and jennies are frequently milked depending on consumer demand, up to eight times a day [10,62,71]. Milking is carried out at least 2 hours after foal separation from the mother [70,72]. This distinctive trait of the dairy equine enterprise introduced the neologism “milking session”, i.e., the interval from foal separation up to the end of each milking [62]. It must be noted that milk ejection is not reported to be affected by the presence of the foal during milking in the dairy donkey farm [68], while it is recommended in the dairy horse farm for a complete oxytocin release [10]. In this regard, the selection for milkability of mares would greatly improve the milking routine, reducing the labor costs [73].
See also the paper by Alabiso, M., et al. "The effects of different milking intervals and milking times per day in jennet milk production." animal 3.4 (2009): 543-547. Reference 67. The Author reports “Total milk yield was 4.87±0.12 kg with eight-time milking frequency (data not shown in Table 2). This milk production could be considered the daily milk yield realizable by the jennets.
Line 77: table 1. “Average daily milk yield of the donkey mare during the lactation season”.
Table 1, must be modified.
Specifically, in the second line (reference 23) you indicates 3 kg of milk, but this milk yield were obtained from 4 daily milkings, therefore approximately 0.75 kg per milking per head.
In line 4 (reference 25), the value of 0.17 kg of milk, was obtained from a single daily milking. The same authors (Ivankovic et al.), in another paper (MILKING CHARACTERISTICS OF ISTRIAN AND LITTORAL DINARIC DONKEY BREEDS, published in Proceedings of the International Symposium on Animal Science 2014, September 2014, Belgrade-Zemun), reported for the Littoral breed Dinarc, 318 ml of milk for milking while in the Istrian breed 745 ml for milking. I recommend that you also enter these data in the table.
In lines 7 and 8, (references 18, 22), the values of 1.64 kg and 1.70 kg of milk, were obtained with 2 daily milkings.
Table 1, must be restructured, inserting the number of daily milkings in brackets, next to each milk production, for example line 3 "China - Jiangyue - 3.00 (4 milking/day).
The mean value of “Daily milk yield” indicated at the end of Table 1, 1.39 ± 0.66, is incorrect and misleading; It must also be deleted from the text.
Line 102: Fig 1. The Authors (reference 29) apply Wood's model (Wood, 1967) to evaluate the shape of lactation curve, in Martina Franca jennies. They use different combinations of the interval time between 2 consecutive milkings and the number of daily milkings. An extensive explanation is needed.
Line 125: “casein”, I don't see numeric values for casein in table 3. Insert some references.
Line 126-127: “DM composition was found to be less than other species such as bovine milk [21]”.
You are comparing the milk quality of different species (monogastric versus polygastric), a short comment is needed.
Line 136: table 4. In “Daily milk yield” insert the number of daily milkings.
In SCC, rewrite in SCC * 1000, cells/ml. Check also in the text.
Line 226-238: check the numbers and rewrite them correctly, example 12500 (line 232) rewrite 12,500. Check also in the text and tables.
Line 250: I suggest to insert in this chapter (Chapter 5), some references, about the relationship between milk cisternal fraction and total milk yield (cisternal / cisternal + alveolar).
Line 295: I suggest to insert in this chapter (Chapter 6), some references, about the donkey milk flow curves, with the description of main milkability traits (maximum milk flow, average milk flow, machine milking time, etc.).
See the paper entitled “Milk flow curve in Amiata donkey breed”, published at ASPA 20th Congress Bologna, June 11-13, 2013, available at web site _ _https://iris.unipa.it/retrieve/handle/10447/99527/130139/Atti%20ASPA%202013.pdf.--Figure 8. Milk flow curve of donkey (Amiata breed, one milking for day).
Line 367-369: I invite the Authors to report ideas, including general ones, on the development lines for a milking machine for horses and donkeys (see Company Siliconform, Germany).
Line 414-415: Elisabetta, S.; Francesco, F. (2012). Equid milk for human consumption. International Dairy Journal 414 2012, 24, 130-142.
Reference is wrong, correct form is: “Salimei, E.; Fantuz, F. Equid milk for human consumption. International dairy journal, 2012, 24.2: 130-142.”
Author Response
Dear Reviewer,
thank you very much for your comments, which were very important for the paper to be of good standard.
Point 1: In this study entitled "Milk Properties and Morphological Characteristics of the Donkey Mammary Gland for Development of an Adopted Milking Machine", the Authors describe the main characteristics of milk yield, lactation curve, milk quality, udder morphological traits and the characteristics of milking machine in donkey breed.
Although the Authors produce a considerable amount of informations, the paper has some limitations that affect its publication in this form, which I summarize below:
Response 1: Thank you for your comments, which are relevant to this manuscript.
Point 2: Line 35: Equus asinus, rewrite in italics.
Response 2: Thanks, I corrected in the manuscript.
Point 3: Line 41-42: Hippocrates (460-370 v. Chr.), rewrite in correct form.
Response 3: Thanks, I corrected in the manuscript (460-370 BC).
Point 4: Line 57-60: “The average daily milk yield over the entire lactation season was 1.39±0.66 kg/d and fluctuated between 0.70 and 3.00 kg/d (Tab. 1). However, the daily milk yield in donkeys is influenced by many factors, such as breed, feeding, stage of lactation, lactation number, foaling season, milking procedure and production country [1,18, 20-22].”
The two sentences must be completely reformulated, in the light of the considerations reported by Miraglia, N.; Salimei, E.; Fantuz, F. Equine milk prodcution and valorization of marginal areas-a review. Animals 2020, 10(2), 353. (Reference 86).
See paragraph “3.1. Equine Milk Yield and Management of the Dairy Equine Enterprise.” The core of the dairy equine enterprise is related to the management of dams and foals, and of the milking practice, showing important differences from the conventional dairy species. Firstly, dams and foals live together until weaning, which occurs at 7 months (for foals) or later; dams won’t start to be milked before 20 d from foaling [10,68]. Secondly, since the equine mammary gland is characterized by small volume, and milk is mainly alveolar [69], milk harvesting can be carried out many times per day. In the Steppes of Central Asia, mares are milked 4–5 times per day [70], while in more intensive dairy farms located in Europe, mares and jennies are frequently milked depending on consumer demand, up to eight times a day [10,62,71]. Milking is carried out at least 2 hours after foal separation from the mother [70,72]. This distinctive trait of the dairy equine enterprise introduced the neologism “milking session”, i.e., the interval from foal separation up to the end of each milking [62]. It must be noted that milk ejection is not reported to be affected by the presence of the foal during milking in the dairy donkey farm [68], while it is recommended in the dairy horse farm for a complete oxytocin release [10]. In this regard, the selection for milkability of mares would greatly improve the milking routine, reducing the labor costs [73].
See also the paper by Alabiso, M., et al. "The effects of different milking intervals and milking times per day in jennet milk production." animal 3.4 (2009): 543-547. Reference 67. The Author reports “Total milk yield was 4.87±0.12 kg with eight-time milking frequency (data not shown in Table 2). This milk production could be considered the daily milk yield realizable by the jennets.
Response 4: Thank you for this hint, as you know, many factors affect donkey milk yield. We mentioned some factors and added more factors after your comment. Certainly, all factors play a major role. The authors of the article you mentioned (Reference 86) focus on the management of dams and foals, the number of milkings per day and the milkability of donkey mares. But we also find the other factors mentioned very important: breed, feeding, lactation stage, lactation number, foaling time, milking method and country of production. Nevertheless, we have mentioned all factors in the manuscript.
Point 5: Line 77: table 1. “Average daily milk yield of the donkey mare during the lactation season”.
Table 1, must be modified.
Specifically, in the second line (reference 23) you indicates 3 kg of milk, but this milk yield were obtained from 4 daily milkings, therefore approximately 0.75 kg per milking per head.
In line 4 (reference 25), the value of 0.17 kg of milk, was obtained from a single daily milking. The same authors (Ivankovic et al.), in another paper (MILKING CHARACTERISTICS OF ISTRIAN AND LITTORAL DINARIC DONKEY BREEDS, published in Proceedings of the International Symposium on Animal Science 2014, September 2014, Belgrade-Zemun), reported for the Littoral breed Dinarc, 318 ml of milk for milking while in the Istrian breed 745 ml for milking. I recommend that you also enter these data in the table.
In lines 7 and 8, (references 18, 22), the values of 1.64 kg and 1.70 kg of milk, were obtained with 2 daily milkings.
Table 1, must be restructured, inserting the number of daily milkings in brackets, next to each milk production, for example line 3 "China - Jiangyue - 3.00 (4 milking/day).
Response 5: Thank you for this hint, the information in the table (1) has been changed and corrected in the manuscript.
Point 6: The mean value of “Daily milk yield” indicated at the end of Table 1, 1.39 ± 0.66, is incorrect and misleading; It must also be deleted from the text.
Response 6: Thank you for this hint, the average daily milk yield has been corrected according to additional information.
Point 7: Line 102: Fig 1. The Authors (reference 29) apply Wood's model (Wood, 1967) to evaluate the shape of lactation curve, in Martina Franca jennies. They use different combinations of the interval time between 2 consecutive milkings and the number of daily milkings. An extensive explanation is needed.
Response 7: Thank you for this hint, the requested information is written in the manuscript
Point 8: Line 125: “casein”, I don't see numeric values for casein in table 3. Insert some references.
Response 8: Thanks for the hint. The requested information is listed in Table 3
Point 9: Line 126-127: “DM composition was found to be less than other species such as bovine milk [21]”.
You are comparing the milk quality of different species (monogastric versus polygastric), a short comment is needed.
Response 9: We wrote this comparison to inform as we can consume both milks. This means that the genetic situation of the animals is decisive for the protein content of the milk and not monogastric and polygastric. We have an example: rabbits are monogastric and their protein content is very high at 12.3%.
Point 10: Line 136: table 4. In “Daily milk yield” insert the number of daily milkings.
Response 10: Thanks for the hint. The requested information is insert in Table 4.
Point 11: In SCC, rewrite in SCC * 1000, cells/ml. Check also in the text.
Response 11: Thanks for the hint. The correct information is inserted into the table. 4
Point 12: Line 226-238: check the numbers and rewrite them correctly, example 12500 (line 232) rewrite 12,500. Check also in the text and tables.
Response 12: Thank you for this comment, all data has been checked and correctly written in the manuscript.
Point 13: Line 250: I suggest to insert in this chapter (Chapter 5), some references, about the relationship between milk cisternal fraction and total milk yield (cisternal / cisternal + alveolar).
Response 13: Thank you for this comment, the requested information is written in the text.
Point 14: Line 295: I suggest to insert in this chapter (Chapter 6), some references, about the donkey milk flow curves, with the description of main milkability traits (maximum milk flow, average milk flow, machine milking time, etc.).
See the paper entitled “Milk flow curve in Amiata donkey breed”, published at ASPA 20th Congress Bologna, June 11-13, 2013, available at web site _ _https://iris.unipa.it/retrieve/handle/10447/99527/130139/Atti%20ASPA%202013.pdf.--Figure 8. Milk flow curve of donkey (Amiata breed, one milking for day).
Response 14: Thank you for this comment, the requested information is written in the text.
Point 15: Line 367-369: I invite the Authors to report ideas, including general ones, on the development lines for a milking machine for horses and donkeys (see Company Siliconform, Germany).
Response 15: Thank you for this advice, donkeys and horses need specific milking machines that take into account all the morphological, anatomical, physiological and economic aspects, allowing a quick and complete milk extraction and maintaining good udder health. So that the special silicone teat liner is developed and the technical basis of the milking machine is created, which is adapted to the requirements of the donkey's udder and teats.
Point 16:
Line 414-415: Elisabetta, S.; Francesco, F. (2012). Equid milk for human consumption. International Dairy Journal 414 2012, 24, 130-142.
Reference is wrong, correct form is: “Salimei, E.; Fantuz, F. Equid milk for human consumption. International dairy journal, 2012, 24.2: 130-142.
Response 16: Thank you for this advice, the correct reference has been written in the text.
Reviewer 2 Report
Dear authors,
- Lines 52 – 54: Reformulate taking into account the introduction and especially the structure of this review.
- Lines 98 – 101: Reformulate, the source of this information is not clear. In addition, I consider that it is not necessary to reproduce an image (figure 1), which has already been published by others.
- Lines 106 – 109: Reformulate, the source of this information is not clear. Is it the observation of the authors of this article or is it taken from other data already published?
- In general, in the chapters that present the chemical composition of milk, there are no references to one of the topics in this review. Are there any changes in the composition depending on the type of milking?
- Chapter 4.5. Vitamin content: I consider that table 5 should be removed and only a summary of the data in this table should be presented.
- Line 260: I believe that this image should not be included in the article (figure 2).
- Chapter 7. Discussion - The authors repeat the data presented in the previous chapters.
- Rewrite the chapter of conclusions, they are not all relevant to the manuscript presented.
- References: About 30% of references is older than 10 years. Find more recent articles to replace older information.
Author Response
Dear Reviewer,
thank you very much for your comments, which were very important for the paper to be of good standard.
Point 1: Lines 52 – 54: Reformulate taking into account the introduction and especially the structure of this review.
Response1: thank you for this advice, the correct information has been written in the text.
Point 2: Lines 98 – 101: Reformulate, the source of this information is not clear. In addition, I consider that it is not necessary to reproduce an image (figure 1), which has already been published by others.
Response 2: Thank you for this advice, the correct information has been written in the text.
In my opinion we have a review, a literature study. Tables or figures can be used to better understand the information in the text.
Point 3: Lines 106 – 109: Reformulate, the source of this information is not clear. Is it the observation of the authors of this article or is it taken from other data already published?
Response 3: thank you for this advice, the information was extracted from the published paper. We wrote it differently.
Point 4: In general, in the chapters that present the chemical composition of milk, there are no references to one of the topics in this review. Are there any changes in the composition depending on the type of milking?
Response 4: The type of milking also plays a role in the composition of the milk. Whether manual or machine milking, udder completely emptied or not, how many milkings are carried out per day, etc.
Point 5: Chapter 4.5. Vitamin content: I consider that table 5 should be removed and only a summary of the data in this table should be presented.
Response 5: Thank you for this advice, in my opinion, the tables and figures are very necessary in a course of study, because you can immediately get an overview of the content and many scientists only look at the tables and figures.
Point 6: Line 260: I believe that this image should not be included in the article (figure 2).
Response 6: Thank you for this advice, we made the figure professionally.
Point 7: Chapter 7. Discussion - The authors repeat the data presented in the previous chapters.
Response 7: Thank you for this advice, discussion is always necessary. This shows the importance of donkey milk for human nutrition and healing. In addition, it gives us the opportunity to increase milk yield and improve quality.
Point 8: Rewrite the chapter of conclusions, they are not all relevant to the manuscript presented.
Response 8: Thank you for this advice, we changed the conclusion in the text.
Point 9: References: About 30% of references is older than 10 years. Find more recent articles to replace older information.
Response 9: As you know, there are few international references on the subject, since in many countries the importance of donkey's milk has not yet been taken into account. Therefore, one finds few new references. Nevertheless, we have tried to use and study new references as far as we can.
Round 2
Reviewer 1 Report
I suggest to the Authors to modify these two sentences
line 320-323: rewrite the sentence in this form:
"An interesting aspect is reported in a field study [109] in which the authors measured milk flow curves and milk production in lactating donkey mares to assess the milkability after using the milking machine set at 42 kPa of vacuum level, 60 cycles/min and pulsation ratio 60:40."
line 3240-326: rewrite the sentence in this form:
"The observed flow curves were characterized by a short plateau phase (0.08 ± 0.13 min), a long increase phase (0.47 ± 0.27 min) and a long decrease phase (0.54 ± 0.37 min), while the total milking time was 1.75±0.49 min."
Author Response
Point 1: I suggest to the Authors to modify these two sentences
line 320-323: rewrite the sentence in this form:
"An interesting aspect is reported in a field study [109] in which the authors measured milk flow curves and milk production in lactating donkey mares to assess the milkability after using the milking machine set at 42 kPa of vacuum level, 60 cycles/min and pulsation ratio 60:40."
line 3240-326: rewrite the sentence in this form:
"The observed flow curves were characterized by a short plateau phase (0.08 ± 0.13 min), a long increase phase (0.47 ± 0.27 min) and a long decrease phase (0.54 ± 0.37 min), while the total milking time was 1.75±0.49 min."
Response 1: Thanks, I corrected these two sentences in the manuscript
Reviewer 2 Report
The quality of this review has been improved, even if some of the comments did not result in changes made by the authors. Probably my point of view does not correspond to the structure thought by the authors.
Author Response
Point 1: The quality of this review has been improved, even if some of the comments did not result in changes made by the authors. Probably my point of view does not correspond to the structure thought by the authors.
Response 1: Thank you for this comment.
