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In general, birds over-consume energy with higher-energy diets, and they will have difficulty maintaining normal energy intake when diets of less than 2,600 kcal ME/kg are offered. In most instances, underconsumption rather than overconsumption is the problem, and so use of higher-energy diets during situations such as heat stress may help to minimize energy insufficiency.
The majority of the world’s laying hens are kept in locations where heat stress is likely to be a major concern at some stage during the production cycle. The problem relates to birds not consuming enough feed at this time, although there are also some subtle changes in the bird’s metabolism that affect both production and shell quality. The key to sustaining production in hot climates is to maintain a positive energy balance. This may involve the use of higher nutrient-dense diets, greater use of fat and synthetic amino acids, texturing of diets, more frequent feeding and perhaps midnight feeding.
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April 30 2008 | Poultry | No Comments »
Traditionally, diet nutrient concentrations decrease over time, with the notable exception of the need for more calcium. Thus, diet protein and amino acid expressed as a percent of the diet or as a ratio to energy decline as the bird progresses through the laying cycle. However this traditionally approach is now being questioned in nutrient content of successive diets is being tempered and/or delayed. Regardless of other nutrients, it is important to increase diet calcium level and to concomitantly decrease the diet phosphorus level as the bird gets older. The need for less methionine is partially related to the need for tempering a late-cycle increase in egg size since this is usually uneconomical regarding egg pricing and the fact that larger eggs have thinner shells. However, the ability to temper eggs size, while sustaining production, through use of less methionine is far from straightforward.
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April 29 2008 | Poultry | No Comments »
The layer’s peak energy needs are most likely met at around 35 – 40 weeks of age, when daily egg mass output is maximized. However, the layer quite precisely adjusts its intake according to needs for energy, and so variable energy needs are accommodated by change in feed intake.
Most Leghorn strains will now commence egg production with feed intakes as low as 80 – 85 g per day, and it is difficult to formulate diets for such a small appetite. For brown-egg strains, initial feed intake will be around 92 – 95 g per day, so formulation is more easily accommodated. For all diets, maintaining the balance of all nutrients to energy is the most important consideration during formulation.
April 27 2008 | Poultry | No Comments »
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