News and analysis on the global poultry
and animal feed industries.
on June 22, 2009

Week 1: Crucial To Feed Conversion

Many factors that ultimately affect feed conversion are mismanaged during the first week to 10 days.

Question:  What can I do to improve feed conversion?

Answer:  Feeding broilers accounts for over 50 percent of the total cost of production. As a result, feed conversion is a major component in a competitive contract. Feed conversion is a ratio of feed consumed to weight gained and the lower this value is, the better the bird is at converting nutrients and energy from feed to protein. The modern high yield broilers are very efficient at converting feed to meat, with examples of feed conversion currently as low as 1.80. There are many examples where flocks have good body weight but poor feed conversion and as a result place poorly in the competitive rankings. The possibility of disease involvement is typically considered. The key observation here, however, is that body weight was average to above average. If a disease issue were involved, the body weight would be lower than expected. So, the question is, What factors affect feed conversion and how can it be improved?'.

Troubleshooting Feed Conversion 

Temperature.  Birds have a thermoneutral temperature range where no caloric energy is used to generate or loose heat. At thermoneutral temperatures, all of the calories from feed are going to growth and development. If the house temperature is too low, the body temperature will drop below the thermoneutral range. The birds will then use feed as fuel to generate heat. Houses should be preheated and floor temperatures on the day of chick delivery should be between 90 and 95 F (see Table 1).

When environmental temperatures are high, birds will tend to eat less feed and the feed consumed will be converted less efficiently. As body temperature increases, the birds will use mechanisms that use energy such as panting to remove heat and maintain a normal body temperature.

Air quality.  New and improved house construction has increased fuel efficiency. As fuel prices continue to rise, some producers feel that lowering the minimum ventilation timers to save fuel is an acceptable tradeoff. Research, however, indicates that prolonged exposure to ammonia concentrations as low as 25 ppm can have negative effects on feed conversion and body weight gain. With direct-fire heat sources, bird respiration and possible increased moisture due to poor drinker maintenance, it is important to ventilate to control humidity within the house. As humidity increases, ammonia concentration increases. Proper ventilation from the day that chicks are delivered to the farm is required to keep humidity and ammonia levels within acceptable ranges to maximize bird performance. Ventilation requirements will depend on house tightness, humidity, and litter conditions. For the first few days of brooding, running one or two 36-inch fans for just 30 seconds will keep air quality within acceptable ranges. Use of litter treatments to reduce the conversion of manure into ammonia can help. If ammonia levels are not kept below 25 ppm, then increased ventilation rates are needed.

Lighting programs.  Light intensity and photoperiod can affect feed consumption and bird activity. Studies have demonstrated improved feed conversion when melatonin, a hormone produced by the pineal gland during dark periods, was fed via water or diet. It is difficult to separate the physiological effects such as increased melatonin concentrations on feed conversion from behavior effects. Reduced light intensity tends to calm the bird, the result will be improved feed conversion due to lower bird activity. In general, it is believed that birds direct more energy to growth in the presence of low light intensity because less energy is devoted to activity. Light intensities of 2.0 to 2.5 footcandles or greater are desired during the first week to encourage more activity while birds learn where food, water and heat sources are located. After the first week, the light intensities can be reduced to 0.5 footcandles.

Water quality.  Water is an essential nutrient, and poor water quality, especially water that has high microbial counts, can result in poor feed conversion. Other contaminants such as iron, manganese, magnesium, etc., can result in biofilms that harbor bacteria. Routine drinker line sanitation and disinfection should be conducted to prevent biofilm buildup and eliminate microbial contamination.

Reward For Early Management 

The first week of the flock will have the most efficient feed conversion. As the birds get bigger and put on more muscle tissue, it takes more of the caloric energy to maintain the body than when the chicks first hatched. Once a chick has been cold stressed, heat stressed or exposed to poor air quality, the damage to feed conversion cannot be repaired. While it is important to manage the flock well through the entire grow-out period, management during the first week is especially important and should not be neglected.

In some cases, producers choose to live with suboptimal conditions to reduce energy expenses. The money saved does not compensate, however, for the money lost on poor feed efficiency. While there are many factors that can result in poor feed conversion, producers who manage their houses to optimize conditions, especially during the brooding period, will be rewarded for their time and financial investment.

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