Toxic Metals in Meat Contributed by Helicopter and Rifle Thoracic Killing of Game Meat Animals

Round 1

Reviewer 1 Report

The total number of samples used in this project was 18, including helicopter neck shots (n = 9) and thoracic rifle bullet shot carcasses (n = 9). Do you consider the sample size representative of the entire study to obtain reliable results?

Author Response

Reviewer 1 comments and responses

 

The total number of samples used in this project was 18, including helicopter neck shots (n = 9) and thoracic rifle bullet shot carcasses (n = 9). Do you consider the sample size representative of the entire study to obtain reliable results?

 

Response to comment 1.

• Sample size: This is similar to the query received from the other reviewer. Indeed, a total of 30 carcasses were randomly selected from the two killing methods. Rifle killing N=18 initially selected for physical hazards analysis X-ray imaging Rifle killing N=18 initially selected for physical hazards analysis X-ray imaging (by the same research team), from this (n=9) carcasses were then randomly selected for heavy metals concentration analysis around the bullet entry wound; this gave a 50% representation of rifle killed carcasses. The killing from helicopter provided (N=12) carcasses of which all were selected for (X-ray) imaging, (n=9) carcasses were selected, thus giving a 75% representation. While this was mainly caused by the budget, the research team feels that the total numbers of samples were representative of the wounds caused in both killing procedures. All samples were collected after chilling before being transported to the X-ray facility at Tshwane University Technology. Both studies (physical and heavy metals) were conducted by the same research team.
• Animals used: Please note that this study forms part of a larger study related to the strategies to reduce hazards on commercially harvested Impala (Aepyceros melampus) carcasses. For this manuscript on heavy metals, 18 animals used (9 from rifle shot and 9 from helicopter shotgun shot).

 

Author Response File: Author Response.docx

Reviewer 2 Report

I have following points for the authors considerations:

- Can you justify the sample size in this study? it was only nine animals while some animals from another study were compared?

- Adding the findings from control in graphs will make it more interesting for the reader.

- Overall, relevance to the interest of international readers seems missing

- Sustainability aspect and future perspectives seems minor or missing

- can you add a schematics of the whole study design?

Author Response

Reviewer 2 comments and responses

 

Thank you for the comments. The following are the responses to the comments:

 

Comment 1 by reviewer: Can you justify the sample size in this study? It was only nine animals while some animals from another study were compared?

Response to comment 1:

• Sample size: This is similar to the query received from the other reviewer. Indeed, a total of 30 carcasses were randomly selected from the two killing methods. Rifle killing N=18 initially selected for physical hazards analysis X-ray imaging Rifle killing N=18 initially selected for physical hazards analysis X-ray imaging (by the same research team), from this (n=9) carcasses were then randomly selected for heavy metals concentration analysis around the bullet entry wound; this gave a 50% representation of rifle killed carcasses. The killing from helicopter provided (N=12) carcasses of which all were selected for (X-ray) imaging, (n=9) carcasses were selected, thus giving a 75% representation. While this was mainly caused by the budget, the research team feels that the total numbers of samples were representative of the wounds caused in both killing procedures. All samples were collected after chilling before being transported to the X-ray facility at Tshwane University Technology. Both studies (physical and heavy metals) were conducted by the same research team.
• Animals used: Please note that this study forms part of a larger study related to the strategies to reduce hazards on commercially harvested Impala (Aepyceros melampus) carcasses. For this manuscript on heavy metals, 18 animals used (9 from rifle shot and 9 from helicopter shotgun shot).

 

Comment 2 by reviewer: Adding the findings from control in graphs will make it more interesting for the reader.

Response to comment 2: We have added the control results in the graphs. Though given the extensive concentration of Lead from the actual samples, the controls reading or results are small and such that on a graph it does not show better.

 

Comment 3 by reviewer: Overall, relevance to the interest of international readers seems missing.

Response to comment 3: We included additional information on current practices by countries producing game meat animals. The findings from these searches processed are that in almost all the developing countries, similar or related ammunition is used for the purpose of game harvesting / culling, hunting for the purpose of meat production. Where this is the case, lead made and fragmenting bullets are generally used. It is important to highlight that worldwide (Toxic metals) such as Pb in food or drugs is controlled and monitored. However, Pb in hunted meat is not monitored (unless it is meat sourced for export purposes). The remaining meat is generally supplied to the local market as well as processing for other game meat products. In these developing countries, there are no clear guidelines on the type of ammunition to use and the target or placement shot.

 

Comment 4 by reviewer: Sustainability aspect and future perspectives seems minor or missing

Response to comment 4: We have included information on sustainability and possible future risks of these practices especially on the issue of possible meat contamination by these ammunitions or killing plans. While suggestions are well described, the viability of some requires new regulations by different countries. With studies such as this one, regulator/s have an opportunity to measure the possible risks and the need for policy changes. Wild life management is growing in countries such as South Africa, Zimbabwe, Austria, Belarus, Croatia, Botswana, and Namibia. These includes the use of meat sourced from processes including trophy hunting, where the head is generally targeted, contamination of other parts of the body (especially the chest cavity) and other areas of the bullet trail remain possible.

Comment 5 by reviewer: Can you add a schematic of the whole study design?

Response to comment 5: A process diagram (Figure 1), highlighting major processes followed for the study are now included. This section looks at the 3 stages of the process from killing and dressing, sampling and handling as well as analysis. This improves the manuscript.

Author Response File: Author Response.docx