A drop in feed intake is one of the most sensitive health signals in finishing pigs. We can quickly identify the problem by following the steps below.
First, confirm that the drop is real
The first step is not to look for the cause, but to confirm “whether intake has really dropped.”
Normal feed intake for finishing pigs ≈ body weight (kg) × 0.03–0.04. A finishing pig weighing 80 kg should consume 2.4–3.2 kg of feed per day. A drop of more than 5% warrants attention; a drop of more than 10% is severe.
Before investigating, first rule out three confounding factors:
First, check whether leftover feed in the trough is creating a false impression of reduced intake because too much feed was provided;
Second, weighing error: record the feed supplied and the leftovers in the same pen for three consecutive days, then calculate the average;
Third, a temporary drop on the day of a sudden weather change: observe for 24 hours to see whether intake recovers. Only begin a formal investigation if the drop lasts for more than 48 hours.
Define the scope
This is a key turning point that determines the direction of the investigation.
Group-wide decrease: If feed intake decreases across the entire finishing house or in multiple pens, first investigate common factors such as the environment, drinking water, and feed. These issues affect a large area, but the cause is often singular, making them efficient to resolve once identified.
Localized decrease: If the issue occurs only in individual pens or a few pens, focus on investigating ventilation dead zones, excessive stocking density, faulty drinkers, or sudden illness in that area. Localized issues can easily be mistaken for group-wide problems, leading to the wrong treatment approach.
Investigate in order
The investigation must follow the correct order: first check “factors affecting everyone,” then check “problems in individual pens.”
First check: Environment
Temperature: The optimal temperature for finishing pigs is 18—22℃. Feed intake begins to decline above 26℃; above 30℃, the decline can reach 20%—30%. Check whether the thermometer is positioned appropriately and whether it is near a heat source or ventilation outlet.
Ammonia: An ammonia concentration of >25ppm is in the warning range and can reduce feed intake and daily weight gain. If a person entering the pig house experiences eye or nasal irritation, ammonia levels are already above the limit.
Humidity: 60%—70% is recommended. Excessive humidity increases ammonia dissolution and respiratory irritation, while insufficient humidity causes dust to become airborne.
Stocking density: Each finishing pig should have a floor area of ≥0.8㎡. Excessive stocking density directly suppresses feed intake among weaker pigs.
Second check: Drinking water
Water pressure and flow rate are hidden switches for feed intake. The flow rate of a drinking device for finishing pigs should be ≥1.5L/minute. Insufficient water pressure prolongs drinking time and reduces water intake, thereby directly suppressing feed intake. Check whether each drinking device is blocked or leaking, and whether the water is cloudy or has an unusual odor. If water is cut off for more than 4 hours, the herd’s feed intake will remain low for 24—48 hours after the water supply is restored.
Third check: Feed
Batch: Has the feed just been changed? During the transition period, gradually mix the feeds over 5—7 days. A sudden feed change can reduce palatability.
Mold: Check the bottom of the feed trough and the feed tower outlet for clumping, heat, or a musty smell. Mycotoxins (especially vomitoxin) are a common cause of reduced feed intake. Vomitoxin >1ppm can significantly reduce feed intake.
Palatability: Feed that is ground too coarsely or too finely, or fat that has oxidized and turned rancid, can affect feed intake.
Fourth check: Management stress
Have there been any vaccinations, group transfers, or pen consolidations recently? A drop in feed intake of 5%—15% within 24—72 hours after these procedures is a normal stress response and usually recovers on its own within 3 days. If it does not recover after more than 3 days, consider whether a secondary disease has developed.
Troubleshooting logic
Why check the environment first, then water, and then feed?
Environmental factors affect the whole group, produce quick results, and cost the least to investigate. Temperature, ammonia, and humidity can be assessed at a glance and by smell, without testing equipment. Water problems affect just as many animals, but investigating them only requires checking a few drinkers. Feed problems require checking the batch and feed tower, so they cost slightly more to investigate. Management stress is a known event and is placed last because it usually has a clear time point and is easy to rule out.
Check broad-scope, low-cost, high-probability factors first, then local, high-cost, low-probability factors. This is the only way to find the cause quickly.
Implementation Plan
Daily records: Record the amount of feed added, the amount left over, and feed intake for each pen. Continuous records are needed to detect abnormalities.
If a decrease of >5% is observed: immediately investigate in this order: “environment → drinking water → feed → management,” and complete the initial screening within 30 minutes.
If a decrease of >10% is observed: While checking the environment and drinking water, take temperature measurements from a sample and investigate whether a group-wide disease outbreak has occurred; submit samples for testing if necessary.
Feed intake is the most honest indicator of the health of finishing pigs. Pigs cannot speak, but the feed trough will tell you everything. If you want to manage precisely, you must quantify!
First, confirm that the drop is real
The first step is not to look for the cause, but to confirm “whether intake has really dropped.”
Normal feed intake for finishing pigs ≈ body weight (kg) × 0.03–0.04. A finishing pig weighing 80 kg should consume 2.4–3.2 kg of feed per day. A drop of more than 5% warrants attention; a drop of more than 10% is severe.
Before investigating, first rule out three confounding factors:
First, check whether leftover feed in the trough is creating a false impression of reduced intake because too much feed was provided;
Second, weighing error: record the feed supplied and the leftovers in the same pen for three consecutive days, then calculate the average;
Third, a temporary drop on the day of a sudden weather change: observe for 24 hours to see whether intake recovers. Only begin a formal investigation if the drop lasts for more than 48 hours.
Define the scope
This is a key turning point that determines the direction of the investigation.
Group-wide decrease: If feed intake decreases across the entire finishing house or in multiple pens, first investigate common factors such as the environment, drinking water, and feed. These issues affect a large area, but the cause is often singular, making them efficient to resolve once identified.
Localized decrease: If the issue occurs only in individual pens or a few pens, focus on investigating ventilation dead zones, excessive stocking density, faulty drinkers, or sudden illness in that area. Localized issues can easily be mistaken for group-wide problems, leading to the wrong treatment approach.
Investigate in order
The investigation must follow the correct order: first check “factors affecting everyone,” then check “problems in individual pens.”
First check: Environment
Temperature: The optimal temperature for finishing pigs is 18—22℃. Feed intake begins to decline above 26℃; above 30℃, the decline can reach 20%—30%. Check whether the thermometer is positioned appropriately and whether it is near a heat source or ventilation outlet.
Ammonia: An ammonia concentration of >25ppm is in the warning range and can reduce feed intake and daily weight gain. If a person entering the pig house experiences eye or nasal irritation, ammonia levels are already above the limit.
Humidity: 60%—70% is recommended. Excessive humidity increases ammonia dissolution and respiratory irritation, while insufficient humidity causes dust to become airborne.
Stocking density: Each finishing pig should have a floor area of ≥0.8㎡. Excessive stocking density directly suppresses feed intake among weaker pigs.
Second check: Drinking water
Water pressure and flow rate are hidden switches for feed intake. The flow rate of a drinking device for finishing pigs should be ≥1.5L/minute. Insufficient water pressure prolongs drinking time and reduces water intake, thereby directly suppressing feed intake. Check whether each drinking device is blocked or leaking, and whether the water is cloudy or has an unusual odor. If water is cut off for more than 4 hours, the herd’s feed intake will remain low for 24—48 hours after the water supply is restored.
Third check: Feed
Batch: Has the feed just been changed? During the transition period, gradually mix the feeds over 5—7 days. A sudden feed change can reduce palatability.
Mold: Check the bottom of the feed trough and the feed tower outlet for clumping, heat, or a musty smell. Mycotoxins (especially vomitoxin) are a common cause of reduced feed intake. Vomitoxin >1ppm can significantly reduce feed intake.
Palatability: Feed that is ground too coarsely or too finely, or fat that has oxidized and turned rancid, can affect feed intake.
Fourth check: Management stress
Have there been any vaccinations, group transfers, or pen consolidations recently? A drop in feed intake of 5%—15% within 24—72 hours after these procedures is a normal stress response and usually recovers on its own within 3 days. If it does not recover after more than 3 days, consider whether a secondary disease has developed.
Troubleshooting logic
Why check the environment first, then water, and then feed?
Environmental factors affect the whole group, produce quick results, and cost the least to investigate. Temperature, ammonia, and humidity can be assessed at a glance and by smell, without testing equipment. Water problems affect just as many animals, but investigating them only requires checking a few drinkers. Feed problems require checking the batch and feed tower, so they cost slightly more to investigate. Management stress is a known event and is placed last because it usually has a clear time point and is easy to rule out.
Check broad-scope, low-cost, high-probability factors first, then local, high-cost, low-probability factors. This is the only way to find the cause quickly.
Implementation Plan
Daily records: Record the amount of feed added, the amount left over, and feed intake for each pen. Continuous records are needed to detect abnormalities.
If a decrease of >5% is observed: immediately investigate in this order: “environment → drinking water → feed → management,” and complete the initial screening within 30 minutes.
If a decrease of >10% is observed: While checking the environment and drinking water, take temperature measurements from a sample and investigate whether a group-wide disease outbreak has occurred; submit samples for testing if necessary.
Feed intake is the most honest indicator of the health of finishing pigs. Pigs cannot speak, but the feed trough will tell you everything. If you want to manage precisely, you must quantify!