1 Breed characteristics of broilers
As early as the beginning of the last century, people made individual selections on the appearance and body size of chickens according to their personal preferences. Chickens didn't grow fast at the time, as there were fewer choices involving chicken growth rates at the time. In the late 1940s and early 1950s, with the advancement of genetic breeding technology, foreign professional broiler breeding companies began to engage in the selection of broiler meat production performance using quantitative genetics technology. In the original breeding farm of broilers, breeders have established a huge group of purebred strains. Breeding experts will select the chickens with fast growth rate, high feed conversion rate, good body development and high meat production rate for breeding when the next generation they bred will be raised to the market weight of commercial broilers.
The selection intensity of modern broiler breeding is particularly high. The breeding rate of broiler core flocks is generally within 1% for males, 7% to 8% for male hens, and 10% to 12% for female hens. This method of high-intensity selection of broiler genes with fast growth rate and high feed conversion rate ensures the rapid development of broiler breeding, so modern broiler chickens show a continuous increase in the genetic potential of fast growth rate, with an annual weight gain of 40-45g. Feed conversion ratio also has -O every year. The increase of 02-0.025 means that each commercial broiler can save 50-65g of feed every year when it is raised to 2.5kg, and the age of commercial broilers reaching 2.5kg weight decreases by about one day every two years. It used to take 52 days for a broiler to reach a body weight of 2.5kg, but now it only takes 42 days.
According to some data, through the breeding work of broiler breeders for 60 to 70 years, the growth rate of modern broilers has been three times that of the late 1940s, and the same 1815g chicken is produced. The feed consumption of modern broilers is higher than that of the last century. The end of the 40s also decreased by a factor of three.
It can be said that the key to the rapid growth of modern broilers is that broilers have breed genes with fast growth speed and high feed conversion rate.
2 Broiler feed
In the long-term broiler breeding practice, it is found that in order to make the broiler's excellent genetics of fast growth rate and high feed conversion rate exerted, it is necessary to feed the broiler chickens with high-energy and high-protein full-price feed. According to the characteristics and nutritional requirements of different stages of broiler growth and development, modern broiler nutrition experts scientifically formulate feed raw materials such as corn, soybean meal, oil, minerals and trace elements to make nutritionally balanced full-price feed to meet the different growth requirements of broilers. Nutritional requirements for developmental stages.
1 chick feed
The crude protein content of chick feed is 21% to 22%, and the energy value is about 3010kcal/kg. At the same time, the feed is rich in minerals and trace elements. The content of mineral elements is calcium 1%, available phosphorus 0.5%, magnesium 0.05%~0.5%, sodium 0.16%, chlorine 0.16%~ 0.22%, potassium 0.4% to 0.9%, the trace element content per kilogram of feed is copper 8mg, iodine 1mg, iron 80mg, manganese 10-0mg, molybdenum 1mg, selenium 0.15mg, zinc 80mg. Typically, broilers are fed chick feed from 1 to 14 days of age.
2 medium chicken ingredients
After the broilers have grown to 14 days of age, they are fed medium feed at this stage 7 days before slaughter. At this stage, the protein content of the feed decreased, and the energy content of the feed increased significantly. Usually, the crude protein content of the chicken feed is about 20%, and the energy value is about 3100kcal/kg. The feed is also rich in minerals and trace elements, and the mineral element content is calcium O. 9%, available phosphorus 0.45%, magnesium 0.05% ~ O. 5%, sodium 0.16%, chlorine 0.16%～O. 22%, potassium O. 4% to 0.9% The trace element content per kilogram of feed is 8 mg of copper, 1 mg of iodine, 80 mg of iron, 100 mg of manganese, 1 mg of molybdenum, 0.15 mg of selenium, and 80 mg of zinc.
3 chicken ingredients
7 days before broiler slaughter, the feed is changed to large chicken feed. The crude protein content of chicken feed is 18% to 20%, and the energy value is about 3200kcal/kg. The content of minerals and trace elements in the feed is sufficient, and the content of mineral elements is calcium o. 985%, available phosphorus 0.42%, magnesium 0.05%-0.5%, sodium 0.16%, chlorine 0.16%-0.22%, potassium 0.4%-0.9%, per kilogram of feed The trace element content is copper 8mg, iodine 1mg, iron 80mg, manganese 100mg, molybdenum 1mg, selenium 0.15mg, zinc 60mg.
It is this nutritionally balanced high-energy and high-protein full-price feed that provides the material basis for healthy and rapid growth of broilers, enabling broilers to exert their genetic potential. Obviously, if the same breed of broiler is fed with low-energy and low-protein feed (such as using pure corn or wheat), it will certainly not grow fast because the energy material cannot meet the needs of the rapid growth and development of broilers.
3 Breeding environment for broilers
The body temperature of newborn chicks is between 39.4°C and 41.1°C, with less subcutaneous fat, relatively less hair, poor heat preservation ability, and poor ability to use energy to produce temperature. After 28 days of age, the feathers begin to grow together, the body temperature regulation mechanism begins to improve, and it gradually adapts to the external environment. At the same time, because broilers have genes for rapid growth and are fed full-price feed with balanced nutrition and high energy value and high protein, their metabolism is very fast, and the requirements for temperature, humidity and air quality are particularly high. To meet these environmental control requirements of broilers, the healthy and rapid growth and development of broilers can be guaranteed.
The ambient temperature of 1-day-old chicks is controlled at 34°C to 35°C. By the time the chicks were 7 days old, the ambient temperature was gradually lowered to 32°C. In the future, with the increase of the chick's age, the temperature will be lowered by 2°C to 3°C every week, and the temperature of the chicken house will be controlled at 21°C when it reaches the age of 35 days. However, it is necessary to gradually reduce the ambient temperature of the chicken house, and the daily temperature difference of the chicken house should not exceed 1 °C to avoid cold stress.
The first week of broiler humidity is controlled at 60%, ~ 65%. after. As the broiler grows, the humidity is gradually lowered to 45% to 65%.
Rapid growth rate and vigorous metabolism make broilers need at least 0.5～o. 6cfm/kg ventilation volume. More important is the requirement for air quality. Broiler breeding experts use automatic ventilation equipment to control the ventilation time of the house to ensure that the oxygen content in the air in the house is greater than 19.6%, the carbon dioxide concentration is less than 0.3%, the concentration of ammonia and carbon monoxide is less than 10ppm, and the dust is less than 3.4 mg/m3.
A modern broiler house installed with a fully automatic environmental control system can easily meet the temperature, humidity and ventilation requirements of the broiler house, providing a guarantee for the healthy and rapid growth and development of broilers. In the past, there was no need to talk about the environmental control of chicken coops when raising chickens in rural areas. The poor breeding environment affects the health of chickens. Even if the same breed is raised and the same feed is fed, the growth and development of chickens will be slow.
4. Hygiene and Epidemic Prevention Measures
The hygiene and epidemic prevention measures of broilers are an important factor to ensure the rapid growth and development of broilers. Modern broiler farms are built far away from people's production and living areas, adopting a closed all-in and all-out feeding and management model. Scientific drug use and health monitoring work to ensure the health of broilers, so that broilers can grow faster away from the influence of diseases.
Five Scientific Feeding Management Technology
In decades of practice, broiler breeding experts have found a feeding and management technology that conforms to the law of broiler growth and development, especially the application of increasing the 7-day-old body weight of broiler chickens and the application of light control technology, which enables broilers to grow quickly and efficiently. feed.
1 Increase the 7-day-old body weight of broilers
According to the research of broiler breeding experts, every lg difference in the 7-day-old body weight of broilers will lead to a difference of 6.7g in the slaughter weight. In order to increase the 7-day-old body weight of broilers, feed the chicks within 6 hours of hatching to stimulate the development of the digestive tract of the chicks and foster good appetite in the chicks. At the same time, although the feed intake of 1-day-old chicks is about 15g, in the first 3 days of brooding, in addition to feeding each 70 to 80 chicks with a feeding pan, place pads under the feeding line or on both sides of the water line. , the area of the pad paper accounts for 1/3 to 1/2 of the rearing area, and sprinkle about 60g of material per chick on the pad paper to let the chicks eat freely. This method allows the chicks to eat as much food as possible. Considering the timid and weak physiological characteristics of newly hatched chicks, they need sufficient light to increase their feed intake. In the first two days of the chicks entering the house, a 24-hour light time and a light intensity of 60 lux were implemented to ensure that the chicks were more active and fed more. After the third day, gradually reduce the light time and light intensity, the light intensity is gradually reduced from 60lux to 30lux, and the light time is generally reduced by 1 hour per day.
When modern broilers are raised to 7 days of age, their body weight can reach more than 4 times the body weight of 1 day old, and even reach 210g. An excellent 7-day-old body weight of a broiler means that the broiler grows well in the brooding stage, laying a solid foundation for the future growth and development process.
2 Lighting Control Technology
After the broiler grows to 7 days of age, the growth rate of its muscles, bones and feathers is significantly accelerated, so that various organs in the body are always in a state of stress, especially the cardiopulmonary function often cannot keep up with the needs of metabolism. Sudden death syndrome and ascites that are unique to broilers are prone to occur. At the same time, compared with the fast-growing muscles, the development of broiler bones appears to be slow, and the broiler will have leg problems. In order to solve the problems of sudden death, ascites and leg disease caused by the rapid growth of broilers, the use of light control technology, that is, by reducing light intensity and light time, reduces the feed intake of chicks. When the feed intake of broilers is reduced, the growth rate is slowed down, which makes the development of muscles, bones and cardiovascular systems of broilers more balanced, and the survival rate of broilers increases.
Usually, when the broiler weight reaches 167g, the light intensity is controlled at 5-101ux, and the light time is reduced to 18 hours; when the broiler is 8-21 days old, the light time is reduced to 16-12 hours; the broiler is 22-12 hours. At 35 days of age, the light time was increased to 18 hours; when the broilers reached 35 days of age, the light time was increased by 1 hour per day until it increased to 23 hours of light time. That is to say, in the 7 days before slaughtering, increase the light time to promote the broiler's feed intake, achieve the purpose of rapid weight gain, and make up for the weight loss of the broiler caused by reducing the light time in the early feeding period.
In addition, modern broiler farms install automated feeding systems and drinking water systems, which reduces the waste of water and materials, ensures the sanitation of feed and drinking water, and reduces the incidence of diseases in the flock. The extensive use of this automatic feeding system has greatly improved the labor efficiency of broiler feeding, and large-scale broiler production has developed rapidly.
Through the understanding of the above five aspects, we know that the key point that modern broilers can grow so fast is that broilers have genes with fast growth rate and high feed conversion rate. At the same time, high-energy and high-protein full-price feed is fed, and the broilers are raised in a chicken house with suitable temperature and humidity and good ventilation. . This is the secret to the fast growth rate of modern broilers!
After cracking the mystery of the fast growth rate of modern broilers, the rumor that "broiler chickens grow fast is caused by hormone feeding" will be self-defeating!