Dr Kristjan Bregendahl

The management guides of all Hy-Line laying hens contain detailed energy and nutrient recommendations that are applicable to a variety of situations and environments for the particular variety of laying hen.

Before the energy and nutrient recommendations for each management guide are updated, Hy-Line conducts meetings with experienced laying hen nutritionists that are responsible for the diets of literally millions of Hy-Line laying hens throughout the world. The energy and nutrient levels that result in excellent production under commercial conditions are discussed for each Hy-Line variety separately and form the basis for the recommendations. Although there are differences in dietary nutrient contents from different farms – not to mention differences in nutritionists' philosophies – the differences are surprisingly small and it is fairly easy to come to a consensus for what energy and nutrient levels that work well under commercial conditions (where diet cost and production performance play a role). Thus, the energy and nutrient levels shown in the management guides are fairly accurate estimates of the hens needs.

Keep in mind though, that the recommendations in the management guide are approximations and that there always are some fine-tuning needed to account for differences among farms' business goals (e.g., many smaller eggs or fewer larger eggs), local conditions (e.g., health status), and regulations (e.g., maximum inclusion levels of certain trace minerals or vitamins).

The amino acid recommendations are based on digestible amino acids, which accurately estimates the portion of amino acids in feed ingredients that are available for synthesis of body and egg protein. By formulating the diets on a digestible amino acid basis, differences in feed-ingredient quality are taken into account. The recommendations for total amino acids are calculated from the digestible amino acid recommendations using the amino acid digestibility values in corn grain (maize) and soybean meal, and are therefore really only valid when ingredients with similar amino acid digestibilities as those in corn and soybean meal are used. The same goes for the recommendation for crude protein, which is based on the crude protein content in a corn and soybean meal diet. Thus, it is strongly recommended that the diets be formulated on a digestible amino acid basis. The recommended daily consumption of amino acids are based on the hens' need for digestible lysine and the recommendations for all other amino acids are calculated based on ideal amino acid ratios.

The minimum recommended daily consumption for linoleic acid (C18:2, n-6) is usually set at one gram per day in the guides, which covers the biological need for this essential (or indispensible) fatty acid. However, the consumption of linoleic acid influences egg weight, so the content in commercial diets is often much higher to ensure a higher intake of two to three grams per day. But, because the business goals of different farms are different – the part about many smaller eggs versus fewer larger eggs – it was decided only to show the minimum biological intake, with the understanding that the prudent nutritionist would increase the dietary content as needed to influence egg weight, but not to let it decrease below what would result in a consumption of one gram per day.

The recommended daily intakes of calcium (Ca), available phosphorus (P), and sodium (Na) are based on what is fed under commercial conditions. These levels result in good bone structure, bone integrity, and eggshell quality. Note that Hy-Line hens need more sodium in the diet than some other breeds of hens and can tolerate these levels just fine without concerns of wet manure. That said, the sodium in the drinking water can add substantial amounts of sodium to the daily intake, and the dietary levels should be adjusted accordingly.

The recommended vitamin and trace mineral levels are based on what gives 'good performance'. These levels should not necessarily be viewed as minimum or maximum amounts and local conditions and experience should be taken into account when deciding on the levels fed to individual flocks. Although there is no specific recommendation for 25-hydroxy vitamin D3, chelated (organic) trace minerals or enzymes in the management guides, the use of any of these can improve performance, make the diets less expensive, and reduce the environmental impact of egg production. However, it is left to the local nutritionist to include these in the diets for specific flocks. All of these are currently used by Hy-Line International for the company's own breeding stock.

Visit Hy-Line's web site to download the Hy-Line management guides [click here].

February 2010