Feeding Strategies to Keep Your Birds Productive all the Way up to 100 Weeks of Age
Over the last 20 years, large improvements in the performance of laying hen flocks have been seen. Production cycles have increased all the way up to even 100 weeks of age, combined with increases in the peak of egg production and improved livability this has resulted in higher number of eggs per hen housed. The birds have also become more efficient, which resulted in decrease in the feed consumed per egg produced has decreased by more than 10%.
This massive improvement is only possible if the environment of the laying hens is optimal, as the final performance is an interaction between the birds genetics and their environment. Genetic progress and longer production cycles have direct consequences for nutrition. In order to get the full genetic potential out of your flock it is important to supply the right daily nutrients at the right time.
When laying hens are kept in production for 100 weeks instead of 60 or 80 weeks, the eggs output and their associated export of nutrients, like calcium, are much higher. As egg mass is increased so much, also the birds’ yolk and egg shell formation is increased enormously. High performing birds need a perfect feeding strategy to maintain the desired performance levels. This paper looks at the factors that should be taken into account when designing a feeding strategy to achieve the full genetic potential out of your birds.
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The birds nutrient intake should be balanced with her nutrient requirements
The actual daily nutrient intake is a result of the diet composition (feed formulation) and the daily feed intake level (feed consumption). The actual nutrient intake should match the daily nutrient requirements in all stages of birds’ development: growth, daily maintenance, and/or production. Nutrient requirement is also influenced by the daily egg mass produced, which is a result of egg weight and the number of eggs produced.
In the period of 18 to 35 weeks of age, the birds are still growing and therefore they need nutrients for growth next to their standard needs for maintenance. Besides, as birds come into production in this period, nutrients are required for egg production as well. Depending on the quality of rearing and the training of the feed intake capacity, feed intake is often limited between 18 and 25 weeks of age and might not cover the total nutritional requirement at that stage. If this happens, your hens will start to lose body weight and they will compensate for the negative balance by lowering their production performance during her complete production cycle. For example, they will lower their production in terms of lower laying rate and smaller egg weights, mortality might be increased, and eggshell quality reduced, resulting in an higher number of second grade eggs.
A nutrient deficiency can also occur when daily feed intake is low due to environmental stressors, like heat stress, change in feeds or disease. In these situations an additional midnight feeding can be offered to the birds in order to increase daily feed intake. Besides daily feed intake, water intake is also important. If birds don’t drink, they will not eat as well. Therefore check the water quality and the water intake regularly.
Amino acid profile and level
In general, three different stages and their ideal corresponding amino acid profiles can be distinguished: growth, growth combined with egg production, and egg production. Although all essential amino acids could be the limiting factor, it is lysine which is most commonly seen as being the limiting factor for growth, while methionine is commonly limiting for the production of eggs.
At start of production it is important to provide a diet with sufficient levels of the essential amino acids available. After reaching the correct egg size and adult body weight (approximately 30-35 weeks of age), the hens should be able to cope with a lower concentration of amino acids. Nevertheless, amino acid levels for birds in production should always be determined based on the daily egg mass produced (laying rate times egg weight) and never on the age of the birds. Meaning that changing the rations in the diet is based on daily egg mass produced and not on age!
Importance of the uniformity of the flock
Because of differences between birds in performance, nutritional requirements must take the uniformity of the flock into account. The feeding strategy should allow the weakest birds to further develop while allowing the best birds to produce at their genetic potential. This can be achieved by respecting a safety margin for the inclusion of digestible amino acids, particularly in a situation where uniformity is rather low. If levels of digestible amino acids are set above the theoretical concentration (+6%) excellent results can be achieved. For example, birds within the same flock but at different production performance levels will consequently show variety in their requirements for methionine. Please keep in mind, it is important to keep your flock as uniform as possible! For brown egg layers a uniformity of at least 85% should be targeted, and for white egg layers a uniformity of 90%.
Changing energy level related to feed intake and body weight
Energy requirements are determined by the bird’s maintenance (like temperature regulation and the daily activity levels), egg production, and growth. The energy consumption is determined by feed composition, feed presentation, and feed management. There is a direct relation between feed consumption and metabolizable energy intake, as laying hens are partly able to adjust their feed consumption according to the energy concentration in the diet. However, this regulation mechanism is not perfect and a higher concentration of metabolizable energy leads to a higher energy intake even though the daily feed consumption is reduced due to an increase in metabolizable energy concentration.
As with all other nutrients, the energy intake is rather challenging around the onset of lay. At the onset of lay, the birds feed intake capacity is still low, whilst the daily requirements are high because the birds are still growing and they have already started with the production of eggs. Therefore, the priority at the onset of lay is to reach adult body weight in order to obtain high and good persistency and the desired egg weight profile during the production cycle. To achieve this, a feed high in metabolizable energy is needed, this diet at the start of lay should be at least higher in energy compared with the diets provided at the end or rearing or later on in the laying cycle. If birds still struggle with gaining enough body weight at start of lay, energy content could be increased by an additional 50 to 100Kcal/kg. After the birds have reached their adult body weights, reached the proper level of daily feed intake and the targeted egg weight, energy levels can be lowered towards the end of the cycle.
The main objective of feeding adult birds all the way up to the end of the cycle, is to avoid birds from getting fat. The prevention of fat birds can be achieved by lowering energy levels and controlling energy intake. This can be achieved by reducing the levels of added fat or oil and increasing the amount of fiber in the diet.
TO BE CONTINUED IN PART TWO