Applying the process of caring, raising, preventing and treating diseases for broiler chickens raised at Dang Van Chien farm, Dong Chanh hamlet, Thinh Duc commune, Thai Nguyen city, Thai Nguyen province - 2

2.2.1.4. Nutritional requirements of broilers

Energy: Chickens are able to convert energy from simple carbohydrates, some complex carbohydrates such as oil and fat, but complex carbohydrates such as cellulose cannot be used by chickens. However, chickens also need a certain amount of cellulose as a buffer to help the digestion process easier. The ratio of fiber in the diet should not exceed 4%. Energy requirements for metabolic purposes vary greatly, so a lack of energy will affect most production processes. For chickens raised for meat, energy requirements are usually higher than for laying.

Protein: this is an important nutritional index that directly affects health, productivity and product quality. It is believed that 20-25

Poultry production is directly affected by protein nutrition. Broilers require a relatively high proportion of protein in their diet to support rapid growth. The body weight of commercial broilers will increase 50-55 times in 6 weeks.

after hatching. A large part of this weight gain is growth of protein-rich tissues.

Water: is an important nutritional component for any living organism, including poultry. Water is not only a conductor that helps animals absorb nutrients better, but water also helps the body eliminate toxins, helping cells function more healthily... Most other animals, including chickens, will need about 50ml of water per kg of body weight per day. When the weather is warm, this need increases slightly and similarly, when the weather is cold, the amount of water chickens need will be less than normal.

Minerals: are the inorganic part of poultry feed, usually accounting for a very small proportion of the feed ration, however minerals play an extremely important role for poultry.

+ Macro minerals: In the body, Ca accounts for 1.3 - 1.8% of body mass, P accounts for 0.8 - 1% of body mass.

+  Trace minerals: trace minerals including copper, zinc, iron, iodine and selenium are also essential for the growth of poultry.

In the body of animals and humans, minerals play an important role in the formation of body tissues such as bones, teeth, blood, flesh tissue... Some minerals play a role in the creation of ion channels such as Na, K... Some others have the effect of stimulating the activity of enzymes, minerals also have the effect of participating in the buffer system in the body...

2.2.1.5. Factors affecting the growth and development of broiler chickens

-  Influence of lineage

Under the same breeding conditions, different breeds will have different growth abilities.

According to the document of Chambers JR (1990) [17], many genes affect the development of chickens. There are genes that affect the general development or affect the development of a group of traits or a few individual traits.

- Influence of hair growth rate and differentiation

The difference in growth rate and body weight of chickens is determined by gender differences, with males growing faster than females.

Feather growth rate is related to poultry meat quality, poultry with fast feather growth rate usually have better meat quality.

- The impact of diet.

Nutrition plays an important role in the growth of poultry. Providing adequate nutrients and a balance between nutrients will help poultry maximize their genetic potential for growth.

Nutrition is one of the important factors determining the growth ability of poultry. When nutritional needs are met, the time to reach standard weight will be reduced.

Chambers JR (1990) [17] reported that the correlation between chicken weight and feed efficiency is quite high (r = 0.5 - 0.9). To promote the growth ability of poultry, it is not only necessary to provide enough energy and feed according to demand but also to ensure a balance of protein, amino acids and energy. Therefore, the chicken diet must be perfect based on the calculation of poultry needs.

- Environmental impact

Environmental conditions have a great influence on the growth of poultry. If environmental conditions are optimal for poultry growth, poultry will be healthy and grow quickly. If environmental conditions are not favorable, they will create conditions for microorganisms to develop and cause diseases that affect the health of poultry.

High temperatures slow down chicken growth, increase mortality rates, and cause great economic losses when raising broiler chickens industrially in tropical climates (Wesh Bunr, 1992 [19]).

Lighting also affects the growth ability because chickens are very sensitive to light, so lighting is an issue that needs attention. In addition, livestock farming is also affected by many different factors such as humidity, ventilation, wind speed and the impact of stocking density on the growth ability of poultry.

The growth of livestock and poultry is always associated with development, which is the process of qualitative change, the increase and perfection of the nature and function of the body. These two processes are closely related and influence each other to create the perfection of the body of livestock and poultry. The growth and development of the body of livestock and poultry follow the rules and are in stages.

2.2.1.6. Common diseases in broilers

During the daily rearing period, it is necessary to monitor the health of the chicken flock to diagnose, detect diseases and have timely treatment directions. During the time of raising chickens, the following diseases are often encountered:

  Chicken with swollen leg joints:

- Reason:

  Caused by bacteria such as Staphylococcus aureus Gr(+), Pasteurella multocida Gr(-), Mycoplasma synoviae, Salmonella Gr(-).

- Symptom:

  The disease causes arthritis in poultry, causing chickens, ducks, geese, quails, with the characteristics of paralysis, lameness, poultry under 3 months old are more seriously ill than other ages. Symptoms include many joints being inflamed at the same time. The most commonly inflamed joints are the knees and ankles, chickens limp, have difficulty walking, are lazy to move, eat less, drink less, joints are inflamed, red, swollen,

When touched, it feels soft, hot and painful. Later, the inflamed joints become stiff and the chicken has difficulty walking. The symptoms are similar to polio due to lack of calcium and phosphorus minerals...

- Lesions:

  Autopsy of paralyzed chickens to check the joints shows milky white fluid inside, joints that have been inflamed for a long time may have pus or curd, the back of the joints are eroded

- Treatment:

  Use DOXY - HENCOLI mixed in drinking water at a dose of 1ml/2 liters of water for continuous drinking for 3 - 5 days, equivalent to 1ml/12-15kg BW/day combined with HERBAL GLUCO KC ELECTROLYTE at a dose of 1-2g/1 liter of drinking water. The above 2 drugs can be mixed in water and drunk continuously day and night for 3 - 5 days to increase the effect of the drug and increase the treatment efficiency.

  CRD disease

- Reason:

Caused by  Mycoplasma gallisepticum  .

Chickens 2-12 weeks old and laying hens are more susceptible to infection than other ages, often getting sick when there is drizzle, monsoon, and high humidity.

- Symptom:

+ Incubation period from 6 to 21 days.

+ Adult chickens and laying hens: slow weight gain, wheezing, runny nose, poor appetite, chickens become thin, laying hens reduce egg production but still maintain at a low level.

Symptoms: rhinitis, rhinorrhea, cough, facial swelling, eyelid swelling, conjunctivitis.

- Disease prevention: follow good veterinary hygiene procedures, keep cages well-ventilated, have appropriate density, suitable temperature, provide good care and nutrition, and give medicine to prevent disease.

- Treatment:

+ MG - 200: dose 1 g/4 liters of water, drink continuously: 3 - 5 days.

+ Tiamulin: dose 1 g/4 liters of water, drink continuously: 3 - 5 days.

+ Poultry and waterfowl: dose 1g/ 2 – 4 liters of drinking water. Coccidiosis

- Reason:

Caused by coccidia of the genus  Eimeria  . Chicks begin to be infected at 9-10 days of age, but the infection rate is highest between 15-45 days of age. Chickens become infected by swallowing coccidia oocysts in food and drinking water. The disease occurs year-round, but is most severe in the spring and summer when the weather is hot and humid.

- Symptom:

+ Sick chickens are lethargic, eat less, drink a lot of water, have ruffled feathers, droopy wings, are sluggish, have sticky droppings around the anus, and have loose, thick, chocolate-colored or muddy-black droppings.

+ If the chicken is seriously ill, the feces will be mixed with fresh blood, the chicken will lose balance, the wings will be paralyzed, the mucous membranes will be pale, the skin and comb will be pale due to blood loss. The rate of illness is high, many chickens will die.

- Lesions:

+ Cecal coccidiosis: the cecum is swollen and filled with blood.

+ Small intestinal coccidiosis: small intestine is distended, intestinal surface hemorrhage has many gray-white spots, inside the intestine there is pink mucus.

- Treatment:

+ Use cocired: dose 4g/1 - 2 liters of water or 100g/500 kg P, use continuously for 3 days, rest for 2 days then use new course if chicken is not cured.

+ Use Gluco - K - C electrolyte: Dissolve in water or mix with food at the following dosage: pigs, chickens, ducks, geese: 2g/liter of drinking water for 3 - 5 days or 100g/40kg of food to increase resistance for chickens.

  Diarrhea caused by  E.coli (Colibacillosis)

- Reason:

I see that chickens of all ages can get sick, especially chicks 3 - 15 days old, the mortality rate is 20 - 60%, adult chickens have mild disease and rarely die. The disease is transmitted directly through infected eggs, the disease spreads quickly in the incubator, in addition, the disease can be transmitted indirectly through food, drinking water and through open wounds in the navel.

- Symptom:

+ At the beginning of an outbreak, sick chickens usually only eat less and the growth of the whole flock slows down. After that, the disease can progress acutely in young poultry flocks.

+ Sick chickens are often lethargic, ruffled, and emaciated. Some have symptoms of fever, runny nose, and difficulty breathing. After a few days, chickens have diarrhea, loose stools with brown, white, or green mucus, sometimes mixed with blood, and then die en masse. Sometimes chickens have swollen joints.

- Lesions:

+ Liver is swollen and hemorrhagic, liver is red and swollen, liver and pericardium have white mucus layer. Air sac membrane has small hemorrhages. Intestinal mucosa is red and swollen, white stool. In poultry in laying period, ovaries are ruptured and atrophied.

- Treatment:

+ Moxcolis: dose 1g/2 liters of water, drink continuously for 5 - 7 days.

+ Bio-Norfloxacin: dose 2g/liter of water, drink continuously for 5 - 7 days.

2.2.1.6. Introduction to specialized drugs

  MG - 200 medicine

It is a combination of two drugs Tylosin Tartrate and Doxycycline HCl.

- Properties:

Doxycycline has a very strong affinity for lung tissue, so it is particularly suitable for the prevention and treatment of respiratory tract infections.

Tylosin Tartrate is an antibiotic in the Macrolide group, which has the effect of killing bacteria such as:  Staphyloccocus, Streptoccocus, Corynebacterium, Bacilusanthracis, Haemophilus, Moraxellabovis, Treponemahyodysenteriae, Mycoplasmahyopneum oniae, M. hyosynovial, M. hyohinis, ... The combination of the two antibiotics above has a synergistic effect that increases the ability to kill bacteria more strongly. Highly effective in preventing and treating respiratory and digestive diseases.

- Indications: MG - 200 is used to treat CRD asthma, CCRD asthma, and swine asthma. Thanks to its reasonable and special formula, MG - 200 increases the effectiveness of the treatment of chicken asthma (CRD), duck cough, head swelling (coryza), swine asthma, pasteurellosis ( Pasteurella ), pleurisy with fluid ( Haemophilus ), pneumonia, pasteurellosis and other respiratory infections in: chickens, ducks, geese, quails, and pigs.

MG - 200 quickly relieves asthma attacks, helps chickens breathe easier and shortens treatment time even in severe and graft-associated cases.

Dosage and administration:

+ Mix with food or drinking water: use for 3 - 5 days.

+ Poultry and waterfowl: 1g/ 2 – 4 liters of drinking water.

  Cocired medicine

Is a combination of Sulfadimerazine and Diaveridine.

- Properties:

Sulfadimerazine is effective against coccidia at all stages. Sulfadimerazine has a rapid effect and is rapidly absorbed in poultry, so it is used to treat coccidiosis in chickens and rabbits.

Diaveridine is an antibacterial agent, used for coccidioidomycosis and enteric infections.

Cocired is a special medicine against coccidia parasites in the small and large intestines that cause diarrhea, bloody stools, slimy stools, and mucus in poultry.

Dosage and administration:

+ Mix food or drink.

+ Poultry and waterfowl: 4g/ 1 - 2 liters of drinking water.

  Moxcolis medicine

- With a special formula for superior treatment of infectious diseases caused by microorganisms sensitive to Amoxycillin and Colistin such as: Gastrointestinal infections caused by  E. coli, Salmonella, Clostridium perfringens ; respiratory infections  caused by Mycoplasma, Hemophilus , septicemia, Coryza; urinary tract infections and MMA syndrome...

Recommended for stress prevention due to vaccination, beak trimming, weather changes, feed transfer or movement of broilers, laying hens, ducks, quails...

Dosage and administration:

+ Poultry: 1g/2 liters of water or 1g/10kg body weight. Treatment course 3 - 5 days.

Mix with drinking water or food. Mixed medicine must be used up within 2 days.

- 3 hours

+ Specification: Packed 500g x 10 packs

2.2.2. Research situation at home and abroad

2.2.2.1. Domestic research situation

In general, poultry farming in our country is developing quite rapidly and steadily in terms of scale, output, quality and efficiency. In which, chicken farming is developing strongly, the impact of breeds, seasons and diseases is also a big problem that needs to be solved because it directly affects the livestock industry.

In our country, research projects on the impact of seasons on broiler chickens are also of interest.

According to Phan Cu Nhan and Tran Dinh Mien, (1998) [9], feather growth rate is a sex-linked genetic trait. In the same breed of chicken, hens have a more even feather growth rate than roosters. This is a hormone that acts in the opposite direction to the sex-linked gene. In the same breed and sex, chickens with faster feather growth rate have better growth and development.

The impact of disease is something that everyone is very concerned about because it not only directly affects livestock but also spreads disease, reduces livestock efficiency and causes economic damage.

According to Nguyen Huu Vu, Nguyen Duc Luu (2001) [16], the causative agent of CRD is  Mycoplasma gallisepticum , the infection rate in Northern Vietnam is 51.6% in commercial chickens, and 10% in breeding chickens, the egg laying rate is reduced by 20 - 30%.

Pham Sy Lang and Truong Van Dung, (2002) [8] reported that CRD can reduce egg laying rate by up to 30%, hatching rate by up to 14% and weight of commercial broilers by up to 16%. In addition, the disease is also associated with

Other diseases such as  Newcastle , infectious bronchitis, septicemia,  E. coli disease ,... have caused epidemics with high mortality rates.

Hoang Huy Lieu (2002) [23] said that CRD is caused by 3 species  of Mycoplasma

Causes : M. gallisepticum, M. synoviae, M. meleagridis.  But mainly species

M. gallisepticum. Mycoplasma  means “fungus-like” and looks like a small, nucleated animal cell under the microscope;  gallisepticum  means “poisonous to hens”. This is evident in the high infection rate in egg-laying hens and the significant reduction in egg production.

Hoang Ha (2009) [25] reported that in nature, the incubation period of CRD is from 3 to 8 weeks of age. CRD is very common in chickens and the rate of chickens infected with this disease is very high: 10 - 15% (in breeding flocks), 30 - 40% (in broiler flocks) and 70 - 80% (in laying flocks).

Nguyen Lan Dung, Nguyen Dinh Quyen, Pham Van Ty, (2007) [4] reported that in 1898, Nocard E. and colleagues first isolated  Mycoplasma  from cows with infectious pleuropneumonia. At that time, it was called pleuropneumonia organism (PPO ) . Later, people continued to isolate PPO from other animals and renamed it Pleuropneumonia- like organism (PPLO ). Since 1955, PPO and PPLO were officially changed to  Mycoplasma.

Truong Giang (2008) [24] said that in broilers: the disease often occurs when the flock is 4 - 8 weeks old, the symptoms are often more severe than in other types of chickens due to the secondary infection of other bacteria, most commonly  E. coli , so in broilers it is also called the combined form of  E. coli  - CRD (C-CRD) with symptoms of decreased appetite, runny nose, tracheal rales, cough, conjunctivitis, watery eyes, swollen head, chickens are lethargic and die after 3 - 4 days of infection, the mortality rate can be up to 30%, the rest grow slowly. In adult chickens - laying hens: the disease occurs when the weather changes, vaccination, moving cages, beak trimming..., the symptoms

The main symptoms are still runny nose, wheezing, poor appetite, chickens become thin, laying hens reduce egg production, hatching eggs produce weak chicks. In some laying hen flocks, sometimes only a decrease in egg production, weak chicks, poor hatching rate appear, but other symptoms do not appear.

Ho Thi Thuan, (1985) [13] reported that industrially raised chickens in some southern areas were infected with 5 types of coccidia : E. brunetti, E. tenella, E. maxima,

E. necatrix, E. mitis.

Author Hoang Thach, (1999) [11], determined that there are 6 types of coccidia parasitizing chickens raised in Ho Chi Minh City and some neighboring areas:  E. brunetti ,

E. acervulina ,  E. tenella ,  E. maxima ,  E. necatrix ,  E. mitis .

According to Duong Cong Thuan, (1995) [14], there are 4 species of coccidia causing disease in chicken farms:  E. tenella ,  E. maxima ,  E. necatrix ,  E. mitis .

Nguyen Thi Kim Lan (2012) [7] and many authors confirmed: coccidiosis often causes serious illness in chicks, adult chickens often carry the disease and are a source of disease transmission, polluting the environment. Therefore, the important measure is to prevent chicks from being infected with coccidiosis.

According to Tran Van Hoa et al., (2001) [5], chickens are infected with coccidiosis only by the oral route through substances that chickens frequently come into contact with such as: food, bedding, feces, dust... Although normally, coccidiosis is associated with improved intensive farming in which a large number of chickens are raised together. It is important to know that any condition leading to overcrowding and accumulation of fecal contamination in the environment can be a precursor to this important disease, so outbreaks of coccidiosis can occur in villages as well as in modern factories.

According to Nguyen Lan Dung et al., (1995) [3],  E. coli  has poor resistance and is killed at 55 0 C in 1 hour and at 60 0 C within 30 minutes. Disinfectants

Common disinfectants such as 0.5% chlorinated water and 0.5% phenol kill  E. coli  after 2 - 4 minutes.

2.2.2.2. World research situation

Brandsch and Biilchel, (1978) [1], feather growth rate is a genetic trait related to the metabolic, growth and development characteristics of poultry. Poultry with fast feather growth rate and early physical maturity have better meat quality.

Kojima et al., (1997) [18] used PCR to detect pathogens belonging to 9 species  of avian Mycoplasma  in live vaccines made from chicken embryos with quite high sensitivity. However, no primer pair has been confirmed to be specific for the entire  mollicus  class without multiplying other bacteria.

Woese et al., (1980) [20] analyzed and compared the 16S rRNA gene sequences of representatives of the genera  Mycoplasma, Spiroplasma, Acholeaplasma  and they suggested that these genera evolved backwards from an anaerobic bacterial branch that was the ancestor of  the present-day Bacillus  and  Lactobacillus  families .

Yogev et al., (1988), [21] used probes on the rRNA gene to detect differences within and between the two species MG and MS .

In 1984, Glison and Kleven studied the effectiveness of using attenuated and killed vaccines to control MG transmission through eggs (cited in Pham Sy Lang and Truong Van Dung, (2002)).

According to Chanbers JR (1990) [17], many genes affect the development of chickens. There are genes that affect the general development or the development of a group of traits or a few individual traits.

According to Siegel and Dumington, (1978) [22], alleles that determine fast feather growth rate are suitable for high weight gain. In the same line of fast feather growth chickens, hens have faster feather growth than roosters.