Final Report for FNC06-604
Project Information
PROJECT BACKGROUND
Our farm had previously focused on horses. We have 40 acres of native grass pasture. Our rabbit production was at the time largely for family use. It has since been expanded to include retail and restaurant sales. We have also added cattle to make better use of rotational grazing.
Horses are about the least sustainable species of livestock there is. As a result of the research for this project we are now beginning to focus more on sustainable practices. Rabbits are probably the most sustainable species there is, and as a result of doing the work for the project, we have come up with a lot of ideas to maximize their sustainability.
PROJECT DESCRIPTION
Goals:
The goal of this project was to see if there is any appreciable difference in the growth rate between Heritage breeds of rabbit and commercial New Zealand rabbits, and to evaluate any differences between these two types of rabbit in a grassfed production system. We also wanted to test the Conjugated Linoleic Acid (CLA) content of the meat to see if any benefit can be derived from the grass fed system, as is the case with dairy products. Conjugated Linoleic Acids are fatty acids found in meat and dairy products, and have been found to have numerous health benefits, including cancer fighting properties.
PROCESS
Construction of “Rabbit Tractors”
• We constructed eight 4x22 foot frames out of PVC pipe. The frames had 1x1/2 inch mesh wire attached with self tapping screws. During the second year, we experimented with making the frames out of 1x2 inch boards and created two more runs. We found the wood frames easier to attach the wire to, but the PVC frames are more durable and easier to clean and disinfect.
• We chose to use the wire frames rather than just putting the rabbits on the ground for several reasons, most importantly to prevent them from digging out and from becoming infected with coccidia, but also to protect the roots of the plants.
Implementation
• Each run consisted of two of the 4x 22 frames laid end to end to form one long run. A simple box was constructed to set on the runs to contain the rabbits. The box has four sides and a lidded top to access the rabbits, but no bottom. The back and part of the two sides were enclosed, and the front and the rest of the sides were made of 1x2 wire. This design worked well even in the most inclement weather. The solid sides provided shade and protection from the weather, and the wire portion provided ventilation and visibility. The boxes moved along the PVC frame as the rabbits consumed the grass.
• Each frame was laid down in the early spring to give the grass a chance to grow through the wire. As they ate the grass down the house moved along the frame, and the grass grew up again behind them.
Management
• Rabbits from each group were weighed weekly to track rate of gain.
Processing
• Rabbits were harvested at the end of the 2008 trial and samples taken and sent to a lab for analysis.
PEOPLE
We received help from Kansas States Meat Science Lab in interpreting the final sample data.
RESULTS
The pellet fed rabbits gained faster than the grass fed rabbits regardless of breed or trial number. This was what we expected, and the data was very consistent in backing it up. Also, the pellet fed rabbits were higher in overall fatty acid percentage, with the exception of one group of American breed rabbits. The CLA content of the meat did not change appreciably with regard to sample or trial. This was not what we expected, based on the differences in grass fed verses non grass fed in other species however as rabbit meat is so lean, it seems to be that there is just too little fat in the meat itself to be affected. The decrease in the percentage of overall fatty acids is significant in itself.
We also found that the Heritage breeds consistently outgained the New Zealand on grass. This was what we hoped to find, and were pleased to have this proved out.
These initial results were encouraging for breeders of Heritage rabbits, however I want to stress that the sample size was very small, and larger groups will need to be tested to substantiate these results.
Below is a summary of the trials and results.
Group, Rate of Gain
A 07 3 P, 0.065
H 07 1 P, 0.064
A 07 1 P, 0.062
A 07 2 P, 0.046
N 08 1 P, 0.0419
A 08 1 P, 0.0396
H 07 3 G/O, 0.0349
H 07 2 G/O, 0.0323
H 08 1 G/O, 0.0298
A 08 2 G/O, 0.0288
A 08 3 G/O, 0.0269
N 08 2 G/O, 0.0248
N 08 3 G/O, 0.023
Group, FA%
A 08 2 G/O, 1.25
N 08 2 G/O, 1.875
H 08 1 G/O, 2.38
N 08 3 G/O, 2.475
N 08 1 P, 2.8
A 08 3 G/O, 4.39
A 08 1 P, 6.83
A = American breed, H = Hotot breed, N = New Zealand
07=2007 trials, 08= 2008 trials, 1,2, or 3 indicates the group number
P=Pelleted diet, G/O=Grass and Oat diet
The trials are color coded to match up the group with the fatty acid results more easily. [Editor's Note: For a hard copy of this summary, please contact NCR-SARE at: 1-800-529-1342 or ncrsare@umn.edu.]
DISCUSSION
While we did not get the expected results in CLA content of the meat, the information and data we gained were very informative. There were clear differences in the amount of total fatty acids among the grass and pellet fed groups, and also clear differences in the Heritage breeds verses the commercial New Zealand. This was a very small sample size, and much more study needs to be done to see if the differences we found bear out over a larger data sample. Also, during the second year the Blanc de Hotot rabbits failed to have litters during the study time so there is very little data from them.
The tractor frames were fairly labor intensive to create, but once constructed, they should function for many seasons. We also learned the hard way, with many bruised knuckles, it is very difficult to screw wire to a round PVC pipe. But again, that should be a one-time project. The wood ones were much easier to create, but I do not expect them to last nearly as long.
The tractor houses were a bit more labor intensive to move regularly. The grass also lasted in varying amounts during different times of the year and dependent upon rainfall. Tractors needed to be moved daily, and we discovered that moving them in the early evening worked best, as they did the majority of their grazing in the later evening.
As expected, a side benefit is the natural fertilization of the ground the tractors ran along. While we did not conduct any soil sampling, the visible difference in grazed and ungrazed ground is noticeable. We also noted anecdotally that rabbits like young ragweed plants.
As an anecdotal note, the rabbits on the tractors did not consume hardly any water from their bottles. Also, during the brutal heat of Kansas summers, they seemed much less stressed than their pen raised counterparts. We did not lose any tractor raised rabbits due to heat stress. We did lose two pen raised rabbits during the same time frame.
After harvesting the samples, we had an opportunity to send what was left of the fryers to two chefs in Maryland. While this was not part of the grant project, we hoped part of the trade off for the slower rate of gain and more intensive labor would be increased flavor, and that turned out to be the case.
The chefs overwhelmingly preferred the Grass fed rabbits, both the New Zealand and American and found the Pellet fed American to be chalky and tasteless in comparison.
As a result of the project, we are looking at a whole grain diet for our rabbits, and have reduced the amount of pelleted feed consumed. We are able to purchase grains locally rather than rely on commercial pellets trucked in from out of state.
OUTREACH
1. We presented the methods and initial results to two different groups at Heifer International in Little Rock, AR. The first group consisted of about 40 employees and volunteers at the Heifer Ranch. We presented a PowerPoint presentation and showed pictures of the construction, implementation and management of the project. This group was very engaged in the presentation, since much of what Heifer does deals with alternative methods of raising animals. The second presentation was at the Heifer International offices, and consisted of veterinarians and education personnel. This group was smaller, only eight people but they were also very interested in the project.
2. We held one small field day for a group of locally homeschooled students.
3. The results of this project will be published in an upcoming issue of the American Livestock Breeds Conservancy’s newsletter. As the breeds we used were largely Heritage breeds, the findings will be of great interest to members.
4. We have created a cd with the PowerPoint presentation on it which is available upon request.
5. A webpage has been constructed with the highlights of the project. It is viewable at rareharebarn.com