October 22, 2023
Nigerian Catfish Farmers
How to calculate the daily dosage of OTC medication applied in feed
Suppose that you have stocked 5000 catfish and after 2 weeks mortality starts and you suspect a bacteria infection. The fish are stocked at an average of 10g (0.01kg) a piece and in 2 weeks they were fed 40kg.
The estimated biomass of the fish will be
5000x 0.01kg+40kgx 1.0(FCR=1)=90kg
The dosage of applying OTC in the feed is 75mg/kg of fish.
So, the dosage on a daily basis for a period of 7 days is :
90kg x 75mg/kg =6750mg
Or approximately 7g.
You feed the fish 1% of the bodyweight on a daily which is 90kg x 1/100=0.9kg
In summary you apply 7g of OTC per day in 0.9 of starter feed for 5-7days.
Note: Mixing the antibiotic I the feed should be carried out with gloves. Normally the antibiotic will stick to the oil-coated feed. If the feed is too dry, you can add a little vegetable oil to make the feed stickly for the antibiotic.
How to calculate the dosage of OTC (Oxytetracycline) medication applied in water )
A concrete tank(pond) has the dimension of 5m x 2m x 0.8m and you want to treat the fish with OTC (oxytetracycline) 40g/m³. You reduce the water level to 0.4m. How much OTC should you use?
Solution
5mx2mx0.4m =4m³
4m³x40g/m=160g
The OTC should remain in tank for at least 4 hours, followed by adding fresh water.
How to calculate the dosage of OTC medication based on the percentage of active ingredients?
The OTC you are buying has an active ingredient of 100g OTC/kg, which means that the medicine has 10% active ingredient. The dosage of 40 g/m³ has to be multiplied by 10=400g/m³
Always try to buy medicine with 100% active ingredient.
The inactive ingredient will pollute the water.
Reduce the water level to 1ft
For instance
If you pond is
5 meters wild
10meter long
And the level of the water is 0.3meter(1ft)
28ml of formaline to 1leter of water
LxBxHx28
5mx10mx0.3mx28ml
=420ml
420ml of formalin is to be apply
