MANAGEMENT ▶▶▶
should be recorded separately from mortality and, if possi- ble, the reason for euthanasia recorded. If higher than ex- pected mortality occurs, it will be necessary to investigate possible causes.
Processing the trial Broilers sampled for processing should be chosen at random, and enough birds sampled so that a sufficient representation of the flock population is achieved. The sample size should be at least 100 birds per house (50 males and 50 females); this ensures that there are enough birds in the sample to account for mortalities, and still have good representation of the flock. Birds should again be sampled from at least three evenly dis- tributed locations throughout each house, with sample points away from doors and walls. Coops or crates should be labelled with house, sex and treat- ment. Ideally each combination will have a unique range of barcoded or numbered bands. The following information should be recorded: • Date • Time of loading at farm • House number • Flock identification • Sex • Breed code • Number of birds sampled per sex • Number of birds banded (band range for each house) • Time of arrival at the processing plant • Number of dead on arrivals (DOAs)
When sampling, banding and weighing the broilers, it is im- portant to equalise the sampling and feed withdrawal time for each treatment. Once birds are caught for sampling, band, sex and weigh all the birds and record their weights to unique band numbers; then load them into a clearly marked live transport crates. Birds should have access to water until they are loaded into crates for transport, and the transport time to the processing plant should be kept to a minimum.
Processing Broilers should be processed at the same time to obtain con- sistent yield results. Notify the processing plant beforehand with the protocol and detailed processing instructions. Trial birds should be kept separate from all other birds on the line. Air chilling is recommended over water chilling due to the possibility of increased water uptake. If it is only possible to water chill, the carcasses must be weighed before they are chilled and as soon as they are removed from the chiller to determine the amount of variability. If it is not possible to ful- ly process trial birds in one day, send all birds through first processing on one day and debone all birds the next day. If data are missing or the carcass band number is incorrect, that bird and its measurements must be discarded from the trial.
Data collection and analysis Collect whole carcass and carcass component weights on an individual bird basis. Specific cuts should be reflective of the product mix of the company. Cuts can vary dramatically be- tween deboners and it is strongly recommended that each deboner be given an equal quantity of each treatment in or- der to remove any possible bias. Once data has been collect- ed, it should be analysed. But not before all outliers or incor- rect data is removed. It is good to keep in mind that rounding numbers can have an impact on results; live weights should be reported to the nearest gram, and carcass yield should be reported to at least 2 decimal places. Extremes should be ex- cluded from the data set, values exceeding ± 3 standard de- viations are out. Parts yield should be calculated as a per- centage of live weight, with the mean, standard deviation and CV% .
Conclusions A well-planned and executed commercial trial can provide valuable information, as well as assist the company in making important economic decisions. To guarantee the best possi- ble outcome it is essential to make sure to handle and test all birds in a similar way to avoid introducing bias to either sex or breed and pay attention to detail throughout the trial. It is important that all parties involved communicate with each other guarantee the success of the trial and the reliability of the results. For reliable results random sampling, sufficient sample size and consistent testing procedures are essential as is correct data collection and analysis procedures. Only then can you make direct comparisons of different breeds.
Trial birds should be kept separate from all other birds on the processing line to ensure that data capture is reliable to the gram.
▶ POULTRY WORLD | No. 4, 2019 31
PHOTO: AVIAGEN
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