This type of antibiotic is produced by Streptomyces or obtained through semi-synthesis and is classified as a broad-spectrum antibiotic. Hydrochloride salts are commonly used, with representative drugs including oxytetracycline, doxycycline, and chlortetracycline. The order of antibacterial potency is: doxycycline > chlortetracycline > oxytetracycline.

Characteristics and Compatibility of Arshine Oxytetracycline

1. Oxytetracycline is poorly soluble in water and dissolves at pH levels below 2 and above 8.
2. It exhibits strong antibacterial activity (as a bacteriostatic agent, with bactericidal effects at high concentrations) and is effective against Chlamydia, Rickettsia, Mycoplasma, spirochetes, Actinomyces, and blood parasites.
3. Clinically, it is mainly used for: intestinal diseases (such as yellow and white diarrhea), swine pneumonia, respiratory diseases, and locally for uterine infections such as endometritis or pyometra, anaplasmosis, bovine theileriosis, actinobacillosis, and leptospirosis.
4. Reasonable combinations:
   • (1) Colistin + Oxytetracycline: Colistin enhances the permeability of oxytetracycline through bacterial cell membranes. Recommended for feed mixing.
   • (2) Oxytetracycline + Tylosin: Used for respiratory diseases; injection recommended. Alternatively, Sodium Sulfadimidine / Sodium Sulfadiazine + Oxytetracycline (injection recommended).
   • (3) Oxytetracycline + Florfenicol + Flunixin Meglumine: Recommended for mixed infections of Mycoplasma and pleuropneumonia (injection recommended).

Quality Assessment of Oxytetracycline Injection

1. High-quality oxytetracycline injection should rapidly dissolve in purified water without precipitation.
2. During storage, the solution should not develop black smoke-like precipitates or crystals.
3. Color: High-quality oxytetracycline injection should be a clear, light yellow to amber solution, made from premium-grade oxytetracycline and excipients.
4. Viscosity: Premium oxytetracycline injections use low-viscosity excipients and special processes to reduce viscosity, making it suitable for clinical injection and mixing.

Characteristics of Doxycycline

1. Also known as doxycycline hyclate, it appears as a light yellow or yellow crystalline powder with a bitter taste. It is easily soluble in water, and its solution is relatively stable but can be affected by water quality (e.g., excessive hardness or heavy metals). The pH of a 1% solution is 2-3.
2. It is a broad-spectrum, high-efficiency, low-toxicity semi-synthetic tetracycline antibiotic, with antibacterial activity 2 to 10 times greater than oxytetracycline! It retains efficacy against bacteria resistant to oxytetracycline and tetracycline.
3. Clinically, it is mainly used for: respiratory diseases in livestock and poultry, colibacillosis, blood parasites, Salmonella, and Mycoplasma infections. It is particularly effective for mixed bacterial and Mycoplasma infections in poultry.
4. Dosage: Calculated based on raw material.
   • Mixed feed: Poultry 100-200g/ton, swine 50-100g/ton.
   • Mixed drinking water: Poultry 50-100mg/L, swine 25-50mg/L.
   • Oral administration: Single dose: 2-5mg/kg body weight for pigs, 10-20mg/kg for poultry, administered once daily for 3-5 days.

Reasonable Combinations of Doxycycline

1. Doxycycline + Florfenicol (2:1): Effective for swine anaplasmosis and mixed bacterial-Mycoplasma infections in livestock and poultry.
2. Doxycycline + Lincomycin: Used for Mycoplasma, streptococcal infections, and respiratory diseases.
3. Doxycycline + Tilmicosin / Tylosin: Used for respiratory diseases, Mycoplasma pneumonia, and ileitis.
4. Doxycycline + Florfenicol + Sodium Sulfadimidine / Sodium Sulfachlorpyridazine: A broad-spectrum formula for mixed infections, high fever, etc., in swine or livestock.
5. Doxycycline + Acetylmethionine: Used for stubborn diarrhea.
6. Doxycycline + Calcium Carbaspirin: Recommended for feed mixing, not for drinking water.
7. Doxycycline + Licorice Granules + Flunixin Meglumine Granules: Enhances the effect of doxycycline.