Impacts of Rumen Degradable or Undegradable Protein Supplementation on Supplement Intake and Performance of Yearling Heifers and Cows Grazing Dryland Pastures
, Janessa Kluth 1, T. J. Carlisle 1, Noah Davis 1, Makae Nack 1, Samuel A. Wyffels 1, Abe Scheaffer 2, Tom W. Geary 3 and Megan L. Van Emon 1,*
Round 1
Reviewer 1 Report
Authors have conducted an interesting study to evaluate two different supplements on intake and performance of beef cows and heifers using Smart Feed devices. Result
Manuscript can be considered after a major revision clarifying the following issues:
- M&M section. Tables 1, 2 and 3 include a chemical composition of supplements and pastures. There is not a methodology related with chemical composition. There is not ingredients used to elaborate the supplements. Please include ingredients and formulation. Please, include procedures and references.
Please include a justification for the large differences of Crude protein content (table 1) between RUP and RDP (27.8 vs 37.0) and how the CP content difference could influence on results.
- Experimental design and statistical analysis are confuse. For heifers (n=40) a CRD design was used and for cows (n=36 2-year old and n=24 three-year old) a RCBD (block criteria: BW and BCS; the heavier cows had the higher BCS? Please clarify) was used. Animal was considered the experimental unit (heifers =40). Does it means 100 experimental units?. L84-85: (n=51; RUP) (n=50. RDP). Does it means n=101 experimental units? Please clarify.
Statistical analysis is confuse. Please clarify the model for CRD and RCBD, including de number of DF for each component.
Table 4. interaction trat x period = P<0.01. What was de model used? Did you use a repeated measure? If so, what kind of covariance structure was used? Clarify the model and components.
Conclusion section: L260 “Our results suggest that salt-limited supplements” I did not find objective, justification and methodology related with salt-limited supplement.
Author Response
Authors have conducted an interesting study to evaluate two different supplements on intake and performance of beef cows and heifers using Smart Feed devices. Result
Manuscript can be considered after a major revision clarifying the following issues:
- M&M section. Tables 1, 2 and 3 include a chemical composition of supplements and pastures. There is not a methodology related with chemical composition. There is not ingredients used to elaborate the supplements. Please include ingredients and formulation. Please, include procedures and references.
Author response: All feed and pasture samples were sent to a commercial laboratory for analysis, we do not have the specific procedures. We have included the ingredients for the RDP and RUP supplements. However, due to the products being proprietary, we cannot include exact inclusion rates.
Please include a justification for the large differences of Crude protein content (table 1) between RUP and RDP (27.8 vs 37.0) and how the CP content difference could influence on results.
Author response: The RDP blocks were formulated to be isonitrogenous with the RUP blocks, but due to differences in ingredient CP from the formulation, this resulted in the difference in protein.
Experimental design and statistical analysis are confuse. For heifers (n=40) a CRD design was used and for cows (n=36 2-year old and n=24 three-year old) a RCBD (block criteria: BW and BCS; the heavier cows had the higher BCS? Please clarify) was used. Animal was considered the experimental unit (heifers =40). Does it means 100 experimental units?. L84-85: (n=51; RUP) (n=50. RDP). Does it means n=101 experimental units? Please clarify.
Author response: The number of cows was incorrect and has been corrected. Thank you for bringing to our attention that we had included our previous analysis in the article. The information has been clarified for better understanding.
Statistical analysis is confuse. Please clarify the model for CRD and RCBD, including de number of DF for each component.
Author response: Additional information for statistical analysis has been included for clarity.
Table 4. interaction trat x period = P<0.01. What was de model used? Did you use a repeated measure? If so, what kind of covariance structure was used? Clarify the model and components.
Author response: Additional information for statistical analysis has been included for clarity.
Conclusion section: L260 “Our results suggest that salt-limited supplements” I did not find objective, justification and methodology related with salt-limited supplement.
Author response: Changed materials and methods to reflect the use of salt as an intake limiter
Reviewer 2 Report
The purpose of this study was to evaluate the effects of degradable: undegradable rumen protein ratio in supplements (30:70 vs 63:37) on supplement intake behavior and performance of yearling heifers and cows grazing dryland pastures
General
This manuscript reports a topic pertinent to contemporary. The manuscript is well written and organized; however, there are few little flaws which in my opinion should be rectified before publication
Introduction
L68-70: Therefore, the objective of this study was to evaluate the differences between RUP and RDP supplementation on supplement intake behavior and animal performance when are offered to heifers or to cows.
L80; Remove “For this study” You can start as: To evaluate treatments effects, a total of 100 female Angus-based cattle (heifers and cows) were used as follows: Yearling heifers (n=40) were used in a…
Table 4 and Table 6: Considering that the supplement sources vary in CP content (27.8 vs 37%) and both supplements contain both RDP (30 and 63) and RUP (70 and 37). In order to be more clear to the readers, it is necessary to show supplement intake and protein intake separately (as is shown in the Table at bottom). In this manner, you can note that, RUP heifers eat more both degradable and undegradable protein than those heifers supplemented with RDP treatment (in both periods)! The same case for cows (but inverse), cows that were fed with RDP, eat more both degradable and undegradable protein compared to RUP cows. This is very interesting as a CP supplemental strategy to ensure adequate intake of both types of proteins. Please, address this in the results and discussion
Protein intake was estimated based on data shown in Table 1
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Treatments1 |
||||
|
Item |
|
RUP |
RDP |
SEM |
|
|
Supplement intake, g/d |
|
|
|
|
|
|
Period 1 |
|
286.31 |
151.87 |
50.82 |
|
|
Period 2 |
|
349.00 |
83.44 |
51.06 |
|
|
Protein intake g/d (Period 1) |
|
|
|
|
|
|
Period 1 (undegradable) |
|
55.71 |
35.38 |
|
|
|
Period 1 (degradable) |
|
24.02 |
20.79 |
|
|
|
Period 2 (undegradable) |
|
67.70 |
19.44 |
|
|
|
Period 2 (degradable) |
|
28.96 |
11.36 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Author Response
The purpose of this study was to evaluate the effects of degradable: undegradable rumen protein ratio in supplements (30:70 vs 63:37) on supplement intake behavior and performance of yearling heifers and cows grazing dryland pastures
General
This manuscript reports a topic pertinent to contemporary. The manuscript is well written and organized; however, there are few little flaws which in my opinion should be rectified before publication
Introduction
L68-70: Therefore, the objective of this study was to evaluate the differences between RUP and RDP supplementation on supplement intake behavior and animal performance when are offered to heifers or to cows.
Author response: Changed as suggested
L80; Remove “For this study” You can start as: To evaluate treatments effects, a total of 100 female Angus-based cattle (heifers and cows) were used as follows: Yearling heifers (n=40) were used in a…
Author response: Changed as suggested
Table 4 and Table 6: Considering that the supplement sources vary in CP content (27.8 vs 37%) and both supplements contain both RDP (30 and 63) and RUP (70 and 37). In order to be more clear to the readers, it is necessary to show supplement intake and protein intake separately (as is shown in the Table at bottom). In this manner, you can note that, RUP heifers eat more both degradable and undegradable protein than those heifers supplemented with RDP treatment (in both periods)! The same case for cows (but inverse), cows that were fed with RDP, eat more both degradable and undegradable protein compared to RUP cows. This is very interesting as a CP supplemental strategy to ensure adequate intake of both types of proteins. Please, address this in the results and discussion
Protein intake was estimated based on data shown in Table 1
|
|
Treatments1 |
||||
|
Item |
|
RUP |
RDP |
SEM |
|
|
Supplement intake, g/d |
|
|
|
|
|
|
Period 1 |
|
286.31 |
151.87 |
50.82 |
|
|
Period 2 |
|
349.00 |
83.44 |
51.06 |
|
|
Protein intake g/d (Period 1) |
|
|
|
|
|
|
Period 1 (undegradable) |
|
55.71 |
35.38 |
|
|
|
Period 1 (degradable) |
|
24.02 |
20.79 |
|
|
|
Period 2 (undegradable) |
|
67.70 |
19.44 |
|
|
|
Period 2 (degradable) |
|
28.96 |
11.36 |
|
|
|
|
|
|
|
|
|
Author response: Total protein, RDP, and RUP intakes have been included in tables 4 and 6 and further results and discussion have been added to the manuscript.
Reviewer 3 Report
Additional remarks:
The topic of the manuscript is interesting for readers, in addition the quality and the scientific significance of this manuscript are appropriate, but I find some problematic parts.
Detailed review:
Title: suggest change the title, my suggestion: delete the “behaviour” phrase and correct to “… on supplement feed intake and performance …”!
Simple summary
This section is no to repeat the abstract!
line 19 (and everywhere): change ate to fed!
Introduction
What was the hypothesis? Please add your hypothesis to the end of this section!
Materials and methods
line 77: please add the precipitation rather by mm!
lines 83-84: please add more information the supplement block (form, size, etc)! It is similar to mineral lick?
Table 1: what were the ingredients of supplements?
What was the threshold value which divides RUP from RDP? Please add more information in Introduction section!
line 97: ad libitum font style is italic!
Results
Table 4: Maybe missing Period 1 and 2 results in an Intake rate item! Please check it!
Table 4 and 5: CV%: Which item (intake or intake rate) does CV% belong to? Please clarify it!
Discussion (and Conclusions)
salt-limited supplementation: if you used this term, please add more information in Materials and Methods section!!
Author Response
Additional remarks:
The topic of the manuscript is interesting for readers, in addition the quality and the scientific significance of this manuscript are appropriate, but I find some problematic parts.
Detailed review:
Title: suggest change the title, my suggestion: delete the “behaviour” phrase and correct to “… on supplement feed intake and performance …”!
Author response: Changed as suggested
Simple summary
This section is no to repeat the abstract!
line 19 (and everywhere): change ate to fed!
Author response: Changed the simple summary to not repeat the abstract
Introduction
What was the hypothesis? Please add your hypothesis to the end of this section!
Author response: Hypothesis has been included
Materials and methods
line 77: please add the precipitation rather by mm!
Author response: changed as suggested
lines 83-84: please add more information the supplement block (form, size, etc)! It is similar to mineral lick?
Author response: block weight was added to lines 90-92
Table 1: what were the ingredients of supplements?
Author response: included in the table footnotes
What was the threshold value which divides RUP from RDP? Please add more information in Introduction section!
Author response: The threshold to determine if a supplement is predominantly RUP vs RDP is greater or less than 50% of the protein type. More information has been added to the materials and methods to clarify the RDP and RUP supplements.
line 97: ad libitum font style is italic!
Author response: changed as suggested
Results
Table 4: Maybe missing Period 1 and 2 results in an Intake rate item! Please check it!
Author response: Treatment x period and period were not significant, and each period were not included in the table
Table 4 and 5: CV%: Which item (intake or intake rate) does CV% belong to? Please clarify it!
Author response: CV% is the variation of daily intake, please see line 144. Also included footnotes in each table
Discussion (and Conclusions)
salt-limited supplementation: if you used this term, please add more information in Materials and Methods section!!
Author response: changed as suggested
Round 2
Reviewer 1 Report
Authors clarified my comments.
