This week, I've been enjoying the 2020 Virtual Poultry Science Association Annual Meeting. Although I miss the face-to-face interactions 1000%, the PSA team has done a great job organizing the virtual meeting, and has made the experience very interactive and fun!
I particularly enjoy the on-demand function to listen to talks. Works wonderful if one has missed a talk or wants to write down the notes. :) There are several nice symposiums, and this is the very first one from yesterday on how to best conduct field & research trials.
Here are my notes for those who could not be here this year~
#1. Dr. Sam Rochell — Applied Broiler Nutrition: Using Research To Model Field Conditions
(University of Arkansas)
Coccidiosis and necrotic enteritis are obviously one of the major concerns in today's broiler production. The protozoan parasite genus Eimeria species is the primary cause of coccidiosis.
Sam talked about the 3 nutritional opportunity zones related to Eimeria cycling: Zone 1: Pre-infection | Zone 2: Peak - infection | Zone 3: Post-infection. For each zone, nutritional opportunities and probability of success from nutritional interventions might be different.
At individual bird level, it is usually one cycle of Eimeria, and that is what we normally do in research to create a challenge model; However, in reality in the field, there are usually multiple cycles of Eimeria replication in a 3-4 week period.
So...Can we try to model flock situation in research?
The answer is yes...different methods in floor pens vs. battery cages.
a). Modeling coccidiosis vaccine cycling in floor pens
In floor pens, a model has been developed by giving the control group anticoccidial drug and not vaccinated, while giving the vaccinated group orally-gavaged live oocyte vaccine on day of hatch. (Reference: Gautier et al., 2020)
b). Modeling Eimeria cycling in battery cages
This can be achieved by giving 3x coccidiosis vaccines at day 0, 7, and 14 (1x, 4x, and 16x coccidiosis vaccine doses, respectively)
The goal is to have the right model that can best represent field situation, and that way hopefully we will be able to better understand how nutritional interventions work.
#2. Dr. Brian Fairchild: Why Monitor Environment in Research: Pen & Field Studies
(University of Georgia)
In nutritional research, we often do not collect environmental data, such as temperature, ammonia, CO, etc....thinking that they "should" be remained uniform. However, if we do not record that information, they might become cofounding factors to our research results — whether we aim to minimize stress or study stress, we need to make sure that the right environment is there.
In research facilities, Dr. Fairchild recommend that we should at least measure temperature, humidity and water consumption. (The challenge to the latter though is to have a very sensitive water meter because research pens are usually small)
How to measure environmental conditions? Some recommendations:
- One sensor is not enough! Get at least two sensors...just in case of equipment failure & to cover location differences
- Could use house controller — but it usually records 24 hr average, high and low temps, might not be as informative as needed. Recommend use Rh/temperature data logger — e.g. Onset UX 100-023 ($200); Onset MX2302 ($200, bluetooth) — both can take 15 min and 1 min interval measurements.
- Water consumption is a very good indicator of water consumption. Just by monitoring whole house water consumption pattern may help identify environment issues. For instance, under optimum house conditions, chicks begin to develop a cyclic drinking pattern within hours, but under environment disruption, water consumption pattern would not be established.
- Two types of air entering a house during cold weather: Inlet air or Leakage air. — In a research trial, would want inlet air as apposed to leakage air, because the latter can cause drafts, temperature uniformity problems, etc. Air is affected by house tightness, which can be measured by a static pressure test — the higher the pressure, the lower leakage is.
Take Home Message
Monitoring environment should be done for every study. Make sure that we really understand whether all treatments have the same environment; environmental variables may help explain outliers in results. And, it never hurts to have too much information.
#3. Dr. Nickki Tillman: Best Practices to Get the Most From Your Field Data
(Nutritional Statistics LLC)
Statistics is no doubt extremely important in any types of research. Nickki did a great job reviewing the basics of statistics: what is a population, what is P-value, what is Type I and Type II errors...Note that Power is the probability of not making Type II errors. Typically we want a power at least 80%. Power increases as sample size increases, as effect size increases, and as variation decreases.
So...How do we test a product in production system?
First, need to make sure there is a statistical model...If we just use average of the values (e.g. live weight from 2 houses) with no statistical model, it does not account for variation within the production system (farm, mixed sex, season, age, etc.) and can lead to incorrect conclusion.
Yes, it is still possible to run paired-house evaluation, but we need to make sure to control these points:
On farm replicated houses | Density | Mortality, Livability | Market age | Strain | Breeder flock age | Sex | Management
(A note on the sex effect — female birds will usually lag behind on growth, and straight-run trial may result in an inconstant Male:Female ratio across replicate pens, leading to incorrect interpretation. )
And for research done in pens within a poultry house, follow the following steps to ensure success:
- Know your pen variation (this can be done by running blank diets...)
- Use the variation obtained to run power test and get the proper sample size
- If it is not possible to increase replications - we will need to reduce variation (e.g. by using single sex, controlling feeder position, water space, location, temperature, etc.)
- People & management is key (right feed in the right pen, accurate data collection)
#4. Dr. Elizabeth Dale: Using field trials to make data-driven decisions
Running field trials have many benefits, yet a lot of challenges. From a field vet perspective, Dr. Dale talked about the important questions to ask before a trial:
- Why do we need a trial in the first place - Is it a new solution or do we have a new problem?
- What is the product intended for? Do we have a problem that this solution fits?
- After suppliers present their research, do our own...(if 3rd party trials have been performed, reach out for comments)
- Ask how suppliers validate their product in the field
Once a trial is decided, communication within the team and with the supplier is critical to set proper expectations — Timeline, who does what, who pays what, what gets shared, and most importantly, both parties need to agree upon how "success" is defined ahead of time.
Then, for the actual trial, proper design is key and we want to control what we can to minimize viability (it goes back to Nickki's talk as discussed above) . In addition, Dr. Dale provided some useful tools and tips:
- Create a trial calendar so it's easy to track when product goes in and out, etc.
- Talk early, talk often, schedule check-ins ahead of time
- Create data collection spreadsheet, prepare any necessary forms, and prepare any sampling kits ahead of time.
After the trial, proper data evaluation comes in important, and decision will be made based on the data — Did the product perform as intended, did it show an ROI, did it meet the pre-agreed upon metrics for success?
In the end, Dr. Dale talked about what products would be considered to have potential — it would those products that
Have demonstrated in vitro mode of action; Have positive pen trial data, and possibly production data; Intelligent, simple written protocol presented; Low cost/low risk; Excellent support
#5. Dr. Jeffrey. T. Hope: A Field Nutritionist's Perspective: The Role of Research Data in Decision-Making
(House of Rawford)
The challenge of bridging scientific research and practice is that "scientifically correct does not necessarily have practical implications, but it is absolutely necessary for proof of concept", and on the contrary, practically relevant may not be scientifically correct, but is necessary for application. For example, the commonly used challenge model works well to help identify efficacy of antibiotic-alternative products; yet in practice, we do not gavage our birds with large doses of pathogenic microorganisms. So what is a more practical/representative model? (Vaccination might be one...and it also goes back to Sam's talk in the beginning)
Other considerations in field research
- Genetics: does the product work across genetics...
- Raw materials: large difference across the world...so it would be almost impossible to just accept research results from Europe or other parts of the world. All veggie diet or alternative proteins may affect product effect, and quality and variability in raw ingredients also have a huge impact.
- Environment: density, feed and water access, litter, lighting programs (see Dr. Fairchild's talk above...)
- Coccidiosis control and antibiotics: What is used in the field...vaccines, chemicals or ionophores? Also, can the product effect last multiple cycles (it is not very often where we'd run multiple cycles for product evaluation...)
- Other additives: In research diet, there's usually no additives used, whereas in field, other additives are common, which may influence outcomes.
Influencers of dietary changes - What role does research play?
- Need an adequate basic science, compendiums, and tables defining the new system... all of these help instill confidence for the nutritionists to make the change.
- Evaluate what population will be affected, and is it worth the change?
- Profitability is the final sale to ownership and shareholders — with adequate data and internal verification, we can determine the ROI.
- Field testing is a must...although they have their imperfections, but will help ensure expected results are present within our own production system.
- Quality research is the foundation of practical nutrition.
- Applied research is necessary for individual production systems, and serves as a decision making tool for nutritionist.
- Collaboration between field nutritionists and researchers is imperative for research to be accepted by the industry.
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