Impact of Calving Difficulty on Lameness in Dairy Cows

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[General comments]

This study examined the relationship between the calving difficulty, the postpartum occurrence of lameness and the milk composition. The results of this study at the field demonstration level are very interesting. However, there are several questions and concerns in the manuscript. Please revise the manuscript according to the comments.

1.       Authors use the terms calving difficulty (CD) and calving ease (CE) interchangeably in the manuscript. For example, in L70 “increasing CD scores (using a 4-point scale system)” but in L134 “ease of calving (CE) (on a 4-point scale: 1- no problem…)”. I think CD score and CE score are same 4-point scale. The conclusion was that calving difficulty has the higher risk of postpartum lameness. The authors also used calving difficulty as a keyword and in all Figures and Tables not “calving ease”. Therefore, the term “calving ease (CE)” in the manuscript should be change to “calving difficulty (CD)” and unified as it causes confusion when understanding the content.

We changed in whole manuscript - calving ease (CE)” to “calving difficulty (CD)”.

2.       Authors must provide a table showing the number of CD, unassisted calving, HL, and LA cows in each farm (herd) and total, even if it is supplemental data. Otherwise, it is difficult to interpret the results and discussion. In addition, please add number of cows in each group in Figure 1, Table 2 and 3.

We added –Table 2.

Table 2. Distribution of cows by lameness and calving difficulty.

CD - calving difficulty; n - number of cows; Lameness score - (1) Normal: The cow walks normally; (2) Uneven gait: the cow walks (almost) normally. In most cases, the back is flat when the cow is standing, but arched when walking; (3) Mild lameness: Abnormal gait with short strides on 1 or more legs; (4) Lameness: the cow is obviously lame on 1 or more legs [14].  

3.       It is not stated how long the milk data was obtained. Please indicate in MATERIALS & METHODS the duration of milk data acquisition. When do the values shown in the results indicate? Is it for the entire lactation period (average of days 0-305) or for a certain period of time? The duration of data acquisition is very important information when considering one of the objectives of this study, which is the impact of calving difficulty and lameness on milk production. Although not mentioned in the discussion, how long do you expect the effects of dystocia and lameness on milk yield and composition to disappear?

We added information –

In materials and methods section-

“. These parameters were registered for fresh dairy cows (from first day till 30 days after calving)”

In discussion section –

“We found that the milk quality, according to number of somatic cells, was better in non-lame fresh dairy cows (from first day till 30 days after calving) (p < 0.05)”

4.       The influence of the calving event on the cause of postpartum lameness is discussed in L237-245. But there seems to be no discussion of why lameness is more common in calving difficulty. This is very important part of the conclusion of this study, so please discuss the reasons for this with references.

In discussion section we added in formation – “According results of our study, we found that lameness is more common in calving difficulty. Lameness is a symptom of pain caused by an injury or disease of the feet or legs (Whay et al. 2017). The transition phase, which occurs around the time of calving, has been identified as an essential risk period, with higher stress due to physiological changes, social variables, and changes in housing that influence the chance of lameness occurring (Bergsten et al., 2015. Lameness is a matter for attention due to its high prevalence and link to pain (Whay et al., 2017). The observed shift in resting behavior pattern when cows transition may have implications for the probability of lameness onset in early lactation. Non-inflammatory alterations in the connective tissue of the corium of the foot occur in periparturient cattle, impairing their resilience to external stressors at this key time (Knott et al., 2007) )[8]. Any decrease in rest may contribute to the loading stress that the hoof is subjected to, hence exacerbating the severity of the lesion that develops. Lameness may be a cause of central sensitization and central nervous system winding-up and the observed behavioral response is consistent with the hypothesis that lame cows are actually susceptible to painful stimuli (Whay et al., 2017). According Calderon et al. 2011 lame cows had longer lying periods during the transition period, and they had considerably more lying bouts per day for 3 days before and after calving than nonlame cows [9]”

[Minor comment]

Title: It might be better “Impact of calving difficulty on lameness in dairy cows”.Because calving difficulty associated to lameness but not calving ease. The title should reflect the results and the conclusion. 

We corrected title to – “Impact Of Calving Difficulty On Lameness Dairy Cows”

The “probability” characters in the significance difference test results are mixed (lowercase, capitals, Italic). Please standardize the format of the "P" in the manuscript, figures and tables.

We corrected characters in the significance difference in whole manuscript to – “P”

L32 Please change the phrase “between calving ease and lameness” to “calving difficulty and lameness”.

We corrected this sentence to – “The aims of our study were to evaluate the associations between calving difficulty and lameness and their effects on milk yield and quality traits”

L33-34 “A total of 4723 calving cases were evaluated based on 4-point scoring system.” The original sentence doesn’t reveal what you appreciated about the calving. Therefore, please replace this phrase to “A total of 4723 calving cases were evaluated for calving difficulty by 4-point scoring system”.

We corrected to – “A total of 4723 calving cases were evaluated for calving difficulty by 4-point scoring system”

L67 Please replace “calving score” to “calving difficulty score”.

We corrected to – “As calving difficulty score increased from…”

L69 “the average productivity … 6.7kg” What does it mean? milk yield?

L73-77

It is unclear from this statement the basis for evaluating the relationship between lameness and milk production and composition. Please clarify the purpose of this research by citing literature related between lameness and milk composition.

We corrected to – “…decreased by 6.77 kg/day

” (per day).

We added information in introduction section – “As part of calving, changes in the pelvic ligaments allow the calf to be born more easily. These changes are not limited to the pelvis but affect the whole body, including in the feet. These changes mean a calving cow is at increased risk of developing clinical lameness [15]. The typical laying and rising behavior of cattle is hampered by severe discomfort in lame cows. Mastitis is more likely in lame cows who spend more time lying down [16]. Bacterial contamination of the bedding might result in tarsal and udder infection [17]. Lameness in cows is associated with lower milk yield (Archer et a.. 2010, Ettema et al. 2010, Green et al., 2010, Reader et al., 2011, Singh et al. 2011) and worsening in their welfare (Green et al., 2010,). Effects of lameness on a decrease of milk production and fertility have been fairly well described in literature; however, little is known of their impact on somatic cell counts and milk composition (Archer et al., 2011, Pavlenko et al., 2011)”

L91 “Lely Astronaut A3 milking robot” please add the company name, city and country.

We added information – “(Lely Campus, Maassluis, The Netherlands)”

(1)  “y_ijk” must be “y_ijkl”.

We corrected to – “y_ijkl”

L154-158, Figure 1

I think it is strange that the percentage of lameness in each CE score exceeds 40%, even though the overall percentage of lameness is 7.1%. The numbers shown in L154-158 do not match the % in Figure 1. Please check again to make sure that the results and values in the Figure presented are correct. Also, please add an explanation to the Figure legend regarding CE score and the n number of each group.

We deleted this Figure and added table 2 and information -

The data in the second table confirm that severe lameness (3-4 points) (3.88 - 5.92 % of cows) was more prevalent in those cows that had dystocia than those that didn't (0.27 - 2.37 % of cows) (Table 2).

Table 2. Distribution of cows by lameness and calving difficulty.

Figure 1 title: Please change to “ Prevalence of lameness by calving difficulty (CD) score in cows”

We corrected to – “Prevalence of lameness by CD (calving difficulty) score in cows”

Figure 2

Please state in figure legend what kind of cattle you defined as calving difficulty and lameness.

Please replace “Cases of calving difficulty” to “Calving difficulty” or “CD”.

We corrected to – “Percentage of dairy cows with dystocia at calving and lameness from 1 to 30 days after calving in different herds”

We corrected to – “Calving difficulty”.

Table2

Please add the definition of “No assistance needed at calving” and “calving difficulty” in the footnote.

L176 “without calving difficulty” please unify other figures or tables. It might be better to “no assistance needed at calving”

We added – “No assistance needed at calving – cows without dystocia; Calving difficulty – cows with dystocia”

Corrected in whole manuscript

Figure 3

The title of the Figure should be listed first, and footnotes should be listed below it.

Please add error bars.

Corrected

Corrected and added error bars.

L185

“(p = 0.007, “ should be “(p = 0.007),”

Corrected to – “…by 1.24 kg (P = 0.007)..”

L196

“higher (0.1%)” should be “0.1% higher”

Corrected to – “…was 0.1% higher than…”

L235-236

These values were not stated in the results section. How did authors derive these values?

We added missing results and table in results section – “The data in the second table confirm that severe lameness (3-4 points) (3.88 - 5.92 % of cows) was more prevalent in those cows that had dystocia than those that didn't (0.27 - 2.37 % of cows) (Table 2).

Table 2. Distribution of cows by lameness and calving easiness scores

CD - calving difficulty; n - number of cows; Lameness score - (1) Normal: The cow walks normally; (2) Uneven gait: the cow walks (almost) normally. In most cases, the back is flat when the cow is standing, but arched when walking; (3) Mild lameness: Abnormal gait with short strides on 1 or more legs; (4) Lameness: the cow is obviously lame on 1 or more legs [14].  

L247-249 

“Calving is a trigger that…” Please cite the references.

We corrected to – “Calving is a trigger that lameness was shown to be substantially more prevalent in the early stages of lactation than in the later stages of lactation [18]”

L256-270

Which results indicate this content? I could not understand which part of the results were based on. At least, there is no data about locomotion (lameness) scores in the manuscript. Please show the all results of them in the result section.

We corrected in discussion section to – “According our results the daily milk yield average was higher by 1.24 kg, milk protein) was higher by 0.04%, milk lactose was higher by 2.1% in non-lame cows as compared with lame cows. These data imply that lameness during early lactation may have a negative impact on milk supply during that lactation. The fact that there is a positive relationship between lameness and milk output during early lactation shows that high production is a risk factor for lameness [20].

L286-288
Please add the reference number.

We added the reference number

Question

Answers

Title:

Line 2: Change ‘Easy’ to ‘Ease’

According firs Reviewer suggestion wie corrected title to – “Impact Of Calving Difficulty On Lameness Dairy Cows”

Simple summary:

Line 20: Please indicate the breed(s) and country of study.

Line 22: Were the animals selected randomly or purposively?

We added information – “Calving scores were recorded in Lithuania between 2018 and 2020 with Lithuanian black and white cows”

Cows were selected purposively. We added information – “The lameness was scored twice a week using a locomotion scoring system from 1 to 30 days after calving”

Abstract:

Line 35-36: The following sentences seem confusing: ‘No cows were lame at calving. Cows 35 were divided into non-lame cows and lame cows.’

Line 37: Briefly indicate the statistical analysis carried out.

We deleted this sentence – “No cows were lame at calving”

We added information – “The normal distribution of all indicators was assessed using the Shapiro–Wilk normality test. Normally distributed milk indicators were expressed as mean ± standard error of the mean. Differences between the mean values of their groups were determined using the Fisher’s least significant difference test. The data for the cow CE score were statistically processed using the Wilcoxon–Mann–Whitney test. We categorized cows by health status, i.e., lame (LA) and non-lame (HL) cows, and according to ease of calving (CE) (on a 4-point scale: 1 – no problem, 2 – slight problem, 3 – problems of assistance needed, 4 - considerable force and extreme difficulty)”

Introduction:

Line 78-84: There is need for more justification of the study. Is the problem the authors are trying to solve global or local? There is need for more information on this.

We added information in introduction section –

“Impact of calving difficulty (CD) on lameness dairy cows is global problem because CD in dairy cattle leads to important economic losses for producers due to calf or dam mortality, decreased milk yields, reduced fertility, and increased veterinary costs [1]”

And –

“As part of calving, changes in the pelvic ligaments allow the calf to be born more easily. These changes are not limited to the pelvis but affect the whole body, including in the feet. These changes mean a calving cow is at increased risk of developing clinical lameness [15]. The typical laying and rising behavior of cattle is hampered by severe discomfort in lame cows. Mastitis is more likely in lame cows who spend more time lying down [16]. Bacterial contamination of the bedding might result in tarsal and udder infection [17]. Lameness in cows is associated with lower milk yield (Archer et a.. 2010, Ettema et al. 2010, Green et al., 2010, Reader et al., 2011, Singh et al. 2011) and worsening in their welfare (Green et al., 2010,). Effects of lameness on a decrease of milk production and fertility have been fairly well described in literature; however, little is known of their impact on somatic cell counts and milk composition (Archer et al., 2011, Pavlenko et al., 2011).

In our past studies we found that cows who did not experience calving problems had greater milk lactose concentrations, whereas higher yielding cows had more calving problems than less productive ones [11]”

Materials and Methods:

Line 87: How were the 10 commercial dairy farms selected?

Line 90: How were the 4723 cows randomized? Please indicate the number of replicates and the number of animals per replicate.

Line 130: ‘their groups’. Which groups are being referred?

Line 132: Why the use of ‘Wilcoxon–Mann–Whitney test’?

Line 136: State the reason for using ‘Fisher's exact test’, especially the range of values that necessitated its use.

We added - The study was conducted in the herds of the Lithuanian Black and White Cattle Breeders Association.

We added - In our dataset, one animal had one calving record (total 4723 records in all herds) and an average of 78 records of milk parameters tested over 30 days (total 368394 records).

We corrected to – “Differences between the mean values of study groups…

We removed this sentence because this test was used in the initial statistical studies for CE scores data but is not used in the final analysis.

We corrected “Chi-square test (χ 2) of independence was used to assess the relationship between the state of health of the cows and the classes of these indicators in milk.

Fisher's exact test was not required, it only confirmed the results of the Chi2 test with a sufficiently large sample and the number of individuals in the categories.

Results:

Line 153: Does each farm stands as an independent group?

We presented average of diseases  of all farms and separately – “Lameness was diagnosed in 7.1% of the 4723 fresh dairy cows tested. Among farms, this indicator ranged from 5.22 to 8.49 percent” In Fig 2 we presented percentage of cows with dystocia at calving and lameness from 1 to 30 days after calving in different herds.

Discussion:        

Line 237-239: Of what relevance are the first two sentences to the current study?

Line 239-245: The sentences here will be more relevant under  ‘Introduction’.

We deleted these sentence.

We added these sentence to introduction section – “As part of calving, changes in the pelvic ligaments allow the calf to be born more easily. These changes are not limited to the pelvis but affect the whole body, including in the feet. These changes mean a calving cow is at increased risk of developing clinical lameness [15]. The typical laying and rising behavior of cattle is hampered by severe discomfort in lame cows. Mastitis is more likely in lame cows who spend more time lying down [16]. Bacterial contamination of the bedding might result in tarsal and udder infection [17]”

Conclusions:

Please state the biological implication of the current findings as concluding remarks.

NB: Please subject the whole manuscript to English Editing.

We added information – “From practical point we can suggest that with identification and treatment of lameness we can decrease dystocia and improve milk quality. It can be a great advantage for the farmers to improve the health of their herds”

Whole manuscript corrected.

References:

Kindly revisit the references for accuracy ad correct formatting.

Corrected and added new references

Question

Answers

L175 There is no definition of “k”. “held h for cow” must be “held k for cow”.

We corrected – “and herd k for cow”

L319 “(p < 0.05)” must be “(P < 0.05)”.

Corrected to – “P < 0.05”

L339 “lamenes.” Please revise “lameness.”

Corrected to – “lameness”

Question

Answers

The second paragraph of the 'Abstract' should be rearranged as follows:

We categorized cows by health status, i.e., lame (LA) and non-lame (HL) cows, and according to calving difficulty (CD) (on a 4-point scale: 1 – no problem, 2 – slight problem, 3 – problems of assistance needed, 4 - considerable force and extreme difficulty). The normal distribution of all indicators was assessed using the Shapiro–Wilk normality test. Normally distributed milk indicators were expressed as mean ± standard error of the mean. Differences between the mean values of their groups were determined using the Fisher’s least significant difference test

We added in abstract section – “We categorized cows by health status, i.e., lame (LA) and non-lame (HL) cows, and according to calving difficulty (CD) (on a 4-point scale: 1 – no problem, 2 – slight problem, 3 – problems of assistance needed, 4 - considerable force and extreme difficulty). The normal distribution of all indicators was assessed using the Shapiro–Wilk normality test. Normally distributed milk indicators were expressed as mean ± standard error of the mean. Differences between the mean values of their groups were determined using the Fisher’s least significant difference test”