Importance of flock uniformity – How can we improve it in broilers?by Torben G. Madsen, Evonik Industries, Health & Nutrition feed additives, Singapore and Jacob R. Pedersen, Lantmaennen Danpo A / S, Denmark DL-Methionine It is well recognized that broiler uniformity is beneficial for optimal performance on farm. With a better homogeneity the nutrient requirements for the individual birds are less variable and less safety margin is needed to meet the requirements of all birds. Therefore, feed cost can be saved and performance improved. However, it is not only on farm level that less variation in bird weight improves efficiency. Today, a large part of broiler meat is purchased by retailers and fast food chains. These customers have rather tight specifications for their purchase and failing to meet these specifications impairs the value of the output from the processing plant. As discussed by Cosgriff (2008), the lower value is related to several stages in the slaughtering and processing of the broilers. It is estimated that the value of carcasses out of spec decreases by more than 40 %. Thus, poor broiler uniformity can be a very costly matter. In this article some of the reasons for broiler variation will be discussed and recommendations will be given to reduce the impact of feed on broiler flock homogeneity. Additionally the actual measurement of homogeneity will be discussed as it is important to be able to detect when homogeneity on farm level is less good in order to actively improve it. Factors affecting broiler uniformity The main reasons for flock variation are related to the breed, sex of the bird, and farm management. For years, one of the major breeding goals has been to improve uniformity by selection of pure lines. This practice has led to much higher homogeneity in genetic potential of today’s broilers. Regarding the sex induced variation it can of course be eliminated by sexing the birds but this practice is quite laborious and costly. With modern broiler breeds the difference in growth pattern of female and male birds up to a certain age has been reduced to a level where most broilers farmers operate with “as-hatched” grow out programs in whole-bird production systems. The main reason for poor uniformity today is related to the very broad term ‘management’. One of the major factors within management is of course feeding practice and in the following we will discuss how that can have an impact on flock uniformity. Effect of feed homogeneity on flock uniformity As genetic potential sets the upper limit for performance the expected variation will decrease when actual performance gets closer to this limit and the further away the actual performance is from the genetic potential the higher the variation can be expected. Thus, all nutrients should be present in sufficient quantities to cover requirements for optimal growth. As variation in nutrient intake can occur due to inconsistent feed composition caused by poor dosing accuracy or incomplete mixing of feed ingredients, it is likely that these two factors affect performance of broilers. However, there are not many studies exploring this effect of feed homogeneity on broiler performance and flock homogeneity, but the few studies that have been conducted clearly show an effect of poor feed homogeneity on performance. Ciftci and Ercan (2003) showed how improved feed homogeneity reduced the variation of slaughter weight in female and male broilers (Figure 1), and Duncan (1989) reported lower performance in broiler starters when feed homogeneity was decreased (Table 1). Figure 1 Effect of feed homogeneity on uniformity of broilers at slaughter (Ciftci and Ercan, 2003). Homogeneidad en el peso del pollo (CV), % 11 10 9 8 7 6 30 12,6 8.7 Homogeneidad del alimento (CV), % hembras c machos It has been argued that poor feed homogeneity mainly affects early life growth like it was shown by Duncan (1989) where feed intake per chick is relatively low and that broilers to a large extent can compensate impaired Evonik Degussa GmbH | Importance of flock uniformity – How can we improve it in broilers? | April 2010 Using the respective response curves the optimum dietary amino acid levels for maximizing weight gain or breast meat yield or for minimizing feed conversion can be derived. Thus. Table 1 Effect of feed homogeneity on broiler performance at 28 days of age (Duncan. e.86 * CV: coefficient of variation in % Dosing and mixing of dry amino acids is favorable for feed homogeneity Flock uniformity is not only determined by the nutrient specifications used for feed formulation but also by how evenly the nutrients are distributed in the feed mix. impaired performance in the starter period is likely to have a negative effect on final weight. 2003) DL-Methionine supplementation (g / kg) 0 Live weight (d 42).8 2646 9. This effect will be most pronounced for methionine or sulphur containing amino acids as they are regarded as first limiting.7 707 8. As the results show there were strong effects on average performance of live weight and breast meat and interestingly the flock uniformity was also strongly improved by the supplementation of DL-Methionine. A trial was therefore conducted where we looked at the effect of graded levels of dietary methionine on variability (CV) for body weight and breast meat yield as a measure for uniformity (Table 2). g CV. g CV.5 630 11.8 362 18. just 22% of all results for liquid applications were good and almost 50% were poor (CV > 10%). g Feed conversion ratio. the response in animal performance to methionine concentration in feed follows the law of diminishing returns. these calculations are normally based on the dietary effects on average performance of a flock but not considering the effects of dietary amino acid imbalance on uniformity of the broiler flock. The question is therefore how we make sure that feed is homogenous and that the amino acids are evenly distributed in the feed mix. However. comparing the performance of dry versus liquid amino acid additions.2 2836 6. This makes the period for compensatory growth shorter and shorter over time and it has been shown in a number of studies that impaired broiler performance in the starter period due to lower amino acid content will affect overall performance. using liquid products for amino acid supplementation in feed production can be regarded as a risk factor for proper feed homogeneity. Thus. The following diagrams (Figure 3) illustrate the results of AMINOBatch® tests which determine the coefficient of variation in feed mixtures. with the constant reduction in days to slaughter the starter period in modern broilers will account for a higher share of total lifespan. Basically. i. Evonik 2009) 37 % 24 % 31 % 47 % 22 % 39 % Dry amino acids addition 5 % CV 5 – 10 % CV Liquid addition of amino acids or hydroxy-analogues > 10 % CV Evonik Degussa GmbH | Importance of flock uniformity – How can we improve it in broilers? | April 2010 Page 2/4 .7 Effect of supplemental amino acid source on homogeneity of active substance distribution in feed mixes (AMINOBatch® test results.82 20 706 1. g / g 773 1. Effect of essential nutrient supplementation levels As mentioned it is well documented that deficient levels of essential amino acids will have a negative effect on performance in broilers.1 543 14.7 1. On the other hand.growth in the starter period during the grower and finisher phase. almost 40 % of all CVs applying dry additives were good (CV < 5%) and almost 80% were good or fair (CV < 10%). % control Weight at day 28. % Breast meat (d 42).5 0. which means that increasing levels of methionine in feed will yield ever smaller increments in performance until reaching a maximum which is determined by the genetic potential of the animal and the prevailing environment and management conditions. poor homogeneity at end of the starter period can be expected to persist until slaughter.74 10 716 1. 1989) Feed homogeneity (CV*). Figure 3 Table 2 Effect of graded levels of DL-Methionine on live weight and breast meat yield in broilers (d 1-42) (Lemme.4 2452 11. % 1831 16.3 0. Compared under equal production conditions in the field. However. (2008). In: Recent Advances in Animal Protein Production. and A. overcome. J. When flock homogeneity is not considered in the payment schemes the experience tells us that it is very difficult to improve. 1529 Pedersen. In this context. Bangkok. Evonik Degussa GmbH. there are now some promising experiences from the Danish broiler industry with photometric imaging of broiler carcasses showing that it is possible to assess carcass size and composition for individual birds at the slaughter house (Pedersen. In contrast. only a very small fraction of the birds was actually within the target range of 1700 to 1900 g when they received feed without DL-Methionine supplementation.04 % DL-Met 0. the body weight distribution curve was calculated for the four levels of DL-Methionine supplementation. 1000 1200 1400 1600 Body weight. The system is based on equations that predict the carcass size and composition based on photos of individual broilers taken from different angels. Feed Sci. Evonik Degussa GmbH. g 1800 2000 2200 2400 2600 Basal diet 0. B. A full implementation of this system will allow to pay farmers based on actual flock uniformity. but according to the project manager Jacob R. S. 31 – 40. Currently the robustness of the system is being evaluated. (1989). Figure 2 Effect of dietary methionine content on body weight distribution (Lemme. As mentioned above the improvement in flock uniformity will have a huge impact on the value of the broilers when processed to the final product. Ercan (2003). Poultry International. Conclusion Poor flock uniformity in broilers can have a huge effect on profitability. 16 – 22 Duncan. Anim. monitoring carcass uniformity using a photometric system to determine broiler carcass conformation in the slaughtering process has shown promising results. A. (2003). This has and still is a major hurdle to Cosgrift. Evonik Degussa GmbH | Importance of flock uniformity – How can we improve it in broilers? | April 2010 Page 3/4 . Lemme. However. the fraction within the target range improved considerably at the highest methionine supplementation level. upon which it is believed that all partners involved in the process chain will focus more on improving homogeneity. M. 2009). As shown in Figure 2. Pedersen the results have so far been promising. J.08 % DL-Met 0. 2003). (2009). June issue p.12 % DL-Met Measurement of broiler homogeneity References Ciftcy. Facts & Figures No. 12:163 – 171 Although everybody can agree that uniformity is important it has been difficult to measure and consequently differentiate between farmers that produce broilers with good flock homogeneity and those with less good results.In addition. The additional value that can be captured through that is to the benefit of all partners in the broiler production chain. Improving feed homogeneity and increasing nutrient levels in the feed as well as using easily mixable nutrient sources can improve broiler uniformity. Pre-VIV Symposium presentation. I. 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