Grain Poisoning in cattle
Feeding cattle grain is a very common practice in this area but it doesn't come without it's risks. One of the most common conditions we see is grain poisoning or acidosis, which can be fatal however the good news is that there is a lot we can do to prevent it!
First of all its important to understand how the ruminants gut works. As we know cattle have 4 stomachs, and the rumen is the largest and most important to us in this article. Within the rumen there are millions of tiny bacteria which work to digest the food cattle eat, and make it into a more readily digestible form. When cattle change feeds rapidly, particularly from grass to grain there is a sudden change in the bacteria. Instead of "good" bacteria, we get a rapid increase in the acid-producing bacteria, and the "good" bacteria will die off. This results in a sudden drop of the pH in the rumen to a highly acidic environment which causes damage to the rumen wall, stop to normal rumen contractions and a very unhospitable environment to the "good" bacteria. It also promotes water being dragged into the rumen, which actually causes the animal to become very dehydrated as all the fluid it has is drawn into the rumen where the rest of the body cannot use it.
Signs of grain poisoning differ depending on how severe the condition is.
Mild: Initially cattle will just get a reduced appetite and become quiet and depressed. Cattle may also start to develop mild diarrhoea. These cattle may recover from just removing them from any grain and then feeding hay only.
Moderate: These animals become obviously sick- heart and respiratory rate increase, bloating occurs and profuse smelly diarrhoea is present. These animals will generally require drenching with large volumes of fluids and buffers to increase the rumen pH.
Severe: These animals can become recumbant and can also develop nervous signs such as staggering and incoordination. These cattle will die without emergency treatment.
Even once cattle recover from these episodes there can be side effects in the coming weeks and months. Cattle with acidosis are more likely to develop liver abscessation, laminitis, chronic rumenitis and polioencephalomalacia (a serious nervous condition).
The golden rule of feeding grain is to do everything gradually! The rumen takes 10-14 days minimum to change the bacteria to suit grain and in this time it is vital to provide plenty of their normal diet as well. Fibre is key in the early days of grain feeding so plenty of roughage is important. Making hay the predominant feed for yarded cattle in the first few weeks of grain feeding is a good way to do this, and gradually increasing the grain daily. Cattle should not be put onto grain feeders with ad lib access straight up without gradual introduction or they will often get grain poisoning.
Some grains are also more potent than others; Wheat and Barley tend to be the worst, where as Sorghum and Corn are less likely to cause grain poisoning due to the differing feed content.
Other options for minimising grain poisoning cases include feed additives. One option that can easily be done by producers is to add buffers to the diet with the idea being that this will help increase the pH of the rumen in the early days. Sodium bicarbonate or sodium bentonite at 2% of the ration can be used in the first few weeks. Other options include ionophores such as monensin, but consultation with a nutritionist is recommended before using these.