Page 12 - National Poultry Newspaper

Figure 1. Mean crude protein level (g/kg) of 35 feed ingredients for Australian (dark grey) and global (light grey) data.
Figure 2. Total sample number of 35 feed ingredients for Australian (dark grey) and global (light grey) data.
To ensure this objective is met, nutrient specifica- tions of feed ingredients must be accurately deter- mined.
simulation of the non- phytate phosphorus con- tent of feed formulated to a ‘minimum’ 0.45 percent NPP level in 2020 revealed that due to the sum of the variation in the ingredient NPP content, the actual di- etary level may range any- where from 0.25 to 0.69 percent.
tions.
Development of a database
on the nutrient content of
Australian feed ingredients
sideration in the database. Within this survey, it was identified that information on digestible protein, di- gestible calcium and fibre – all fractions – were rated as important by all nine nutritionists surveyed, as there is presently a lack of data for these specifica-
FEED represents the primary cost of poultry production, thus the for- mulation of cost-effective diets that meet poultry nutrient requirements is critical.
necessarily expensive. Additionally, it has been shown that the normal amount of variation within poultry diets may lead to
Due to the tight time con- straints and fast pace of the industry, feed ingredients delivered to the feed mill are unable to be analysed via wet chemistry.
It was calculated that the variation found in a practi- cal broiler diet is enough that 12.9 percent are ex- pected to have less than 0.40 percent NPP and 12.8 percent are expected to have more than 0.50 per- cent NPP.
Data were sourced and compiled from a total of 12 company databases and further data were sourced from journal articles and published open-access da- tabases.
Consequently, near- infrared spectroscopy calibrations are often used within integrated opera- tions to estimate the nutri- ent composition of feed- stuffs.
Data were collected for 42 ingredients with 102 nutrient specifications per ingredient, where all data were available.
However, these readings often end up being re- ceived as ‘historical’ data, as it can be a month before they reach the nutrition- ist due to practical con- straints, thus they are not available at the time of diet formulation.
Thus, the normal lev- els of variation within industry may be enough to induce leg issues such as phosphorus rickets or tibial dyschondroplasia.
The majority of data is recent, from within the past five years, with the exception of some older data where information was lacking.
practical problems.
A 10,000-observation
Features
Furthermore, consultant nutritionists often do not have access to NIR and must rely on book values.
From these data, the overall mean, total sam- ple number and average standard deviation report- ed was calculated for both Australian data and global data.
As an example, in a re- cent survey of the Austral- ian poultry industry, only 40 percent of nutritionists who formulate diets for layers had access to NIR.
Therefore, a compila- tion and review of recent Australian and global feed ingredient data for commonly used Austral- ian feed ingredients was completed to assist nutri- tionists to understand the variation that exists within our feed ingredients.
The sample size required to predict the mean value for each nutrient specifica- tion to 90 and 95 percent accuracy was also calcu- lated.
Therefore, Australian nu- tritionists have expressed concern, as many nutri- ent specification databases contain dated information or lack Australian specific data.
The sample size required for an accurate estimation of the mean of a popu- lation was determined from the standard devia- tion from the dataset – the ‘sub population’ – N = (Z*SD/E)2.
Variability and uncer- tainty in feed ingredient specifications is a chal- lenge for the poultry in- dustry, as wider safety margins must be applied to formulations to ensure the minimum nutrient re- quirements of poultry are being met.
The database
However, increasing safety margins raises diet cost and thus compromises profitability.
This project funded by AgriFutures Chicken Meat compiled recent – within the past five years – Aus- tralian and global data into a database of nutri- ent specifications for com- monly used feed ingredi- ents within the Australian poultry industry.
Where N is the sample size, Z or Z-score = 1.96, SD is standard deviation, which is the average cal- culated from the dataset, and E the margin of error is calculated as +/− 5 and 10 percentage units.
Therefore, it is important to have an understanding of the variability that may be present within our Aus- tralian feed ingredients – if this is underestimated, diets may not meet mini- mum requirements, and it if this is overestimated, then feed costs may be un-
This database also evalu- ated the variation within feed ingredients for both Australian and global nu- trient specifications and identified areas which re- quire further study.
For example, if dry mat- ter = 884 g/kg = 88.4 per- cent, a margin of error of one percentage unit is equal to 0.884.
Finally, databases used by nutritionists come from various sources – however, cross-checks of each fig- ure contained in a data- base are tedious and costly, and the determination and use of some nutrients have been constantly evolving.
The mean value, sample number and standard de- viation were collected for each nutrient specification.
Initially, Australian poul- try nutritionists were sur- veyed to identify the most common feed ingredients and key nutrients for con-
The database has been published online and may be accessed in PDF at ag rifutures.com.au/product/ database-of-the-nutrient- content-of-australian-
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Page 12 – National Poultry Newspaper, July 2022
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