Clover is an excellent forage for beef cattle as it contains very high nutritional value. The high amount of crude protein and total digestible nutrients (TDN) makes it an excellent food source that promotes cattle health and weight gain. But too much clover can be a bad thing for cattle.
In certain situations, YES, clover can kill cattle because it causes them to bloat, and bloat – at excessive levels – causes death.
What is Cattle Bloat?
Cattle bloat is defined as the excessive buildup of gases in the rumen. As a natural part of the digestion process, gases are created in the rumen. Cattle release this gas by belching while they are chewing their cud. Cattle need to be able to release this gas to avoid uncontrolled expansion in the rumen that will restrict their ability to breathe.
Cattle can bloat for a variety of reasons, including acidosis in the rumen from eating certain grains, natural tendency to bloat due to physiological characteristics, laying down in a position where they can’t get their head and neck elevated enough to release gas, and from eating a large amount of legumes, like clover.
How Does Clover Kill Cattle?
Clover can kill cattle through a process called ‘frothy bloat’. This happens when a foam forms in the rumen and traps gases, making it impossible for cattle to release these gases through belching. High protein forages like clover and alfalfa cause frothy bloat. This most commonly happens when cattle are introduced into a fresh pasture that has a very high percentage of clover or alfalfa in it, and the cows are particularly hungry. When they consume high volumes of clover or similar legumes/high protein grasses, the rumen fills up with this froth-creating substance, and bloat occurs. Cattle can bloat and die within hours of being introduced to a fresh clover pasture. This is a very serious condition that is difficult to treat, but it can be avoided.
How do you Prevent Clover from Killing Cattle?
The best way to prevent frothy bloat is to not give cows access to fresh pastures with too high a clover content. This is typically not a problem in managed grazing systems of perennial pastures because these pastures contain a good mix of clover and grasses. If there is enough variety in the diet, clover will not build up in the rumen in high enough volumes to cause bloat.
Sometimes even in mixed forage pastures, growing conditions can favor clover such that it’s present in really high levels at certain times of year. Also, some pastures are planted in clover and having a high percentage of clover is not avoidable. Here are some tips to help prevent frothy bloat caused by clover and similar forages:
Manage for diversity
Having a well balanced pasture with lots of diversity of grasses and legumes is good for cattle in a variety of ways. Different forage options allow cattle to selectively graze to balance their nutritional requirements. It also prevents cattle from being able to get ‘too much of a good thing’ like grazing dangerously high levels of bloat-causing clovers.
Time the grazing
If you do have a pasture with dangerous levels of clover, you can manage the timing of grazing to minimize problems. Do not move cattle into a clover pasture on an empty stomach. If they are moved partway through an existing grazing period they won’t be able to fill their stomach with a high percentage of clover.
Bloat tends to be worse when grazing wet pastures. Don’t allow cattle into a clover-rich pasture when the grass is wet from dew or rain. Wait till it’s dry to lessen potential problems. Clover that has experienced a hard frost has less tendency to cause bloat, so grazing after a frost is a good option as well.
Another option is to feed some dry hay to cattle before or during grazing of clover-rich pastures, which will add to the mix in the rumen contents and lower bloat risk.
Don’t graze these pastures
If you have high risk clover pastures, it might be a better option to not graze these pastures at all, and instead harvest them for hay or silage. Feeding them later in this form will eliminate bloat risk. Even if you can’t harvest or graze these pastures at all, allowing the clover to persist unharvested is still beneficial to the pasture as it fixes a great deal of nitrogen in the soil and adds to its fertility.
Pick the right legume
Some legumes are worse for bloat than others. For instance, white clover is probably the worst in causing bloat, while red clover is still high risk but not quite as bad. Alfalfa is high risk as well, but some legumes, like birdsfoot trefoil and varieties of vetch, cause no bloat. If you want to incorporate legumes in your pastures and don’t want the bloat risk, choosing a low bloat species or variety is a great option.
Use anti-foaming agents
Old fashioned bloat remedies like linseed oil and turpentine can be sprayed on clover pastures or incorporated into the water source. These are anti-foaming agents that will prevent the froth from forming. Newer products are available that work as well or better. Some farmers recommend baking soda for bloat, but this is a common remedy for acidosis-caused bloat, which is different than frothy bloat.
What do I do if my cow has bloat from clover?
There are a range of options for treating bloat in cattle, but they all have one thing in common: time is of the utmost importance. If you wait too long and the bloat gets worse, it will be too late. Knowing when to intervene can be a difficult judgement call. I’ve often watched cows and calves with big ‘bloated up’ stomachs and thought I had to intervene right away. Sometimes I did, sometimes I didn’t. What I learned was that most of the time the large stomachs weren’t an immediate bloat emergency, and the cattle did fine at eliminating the gases on their own. How do you know when to intervene? If a cow is not chewing it’s cud and is bloated up, you have a problem. When the cow can’t get up, you have a problem. Sometimes these conditions aren’t met and you still have a problem, but without a lot of experience it’s hard to tell.
Keep the animal moving
By remaining in motion, a bloating animal can shift its stomach contents around and allow some gas to escape. This is probably the best first step when you see a bloat problem: keeping the animal moving can help relieve the problem, or at least help keep things from getting worse fast. While walking behind the animal when you get it moving, and keeping an eye on it, you can determine whether further intervention is needed.
Use a stomach tube
It can be difficult to get an animal into a situation where you can effectively administer treatment, but as things worsen, they may be less able to run away and you may be able to treat them. If you can walk them to a squeeze chute, or if they are far enough along in the bloat process to be unable or unwilling to get away from you, try tubing the stomach.
A length of garden hose or similar tubing material can be inserted down the throat and into the stomach to try releasing the gas. With free gas bloat, this is a common treatment that works well. With frothy bloat that’s caused by clover, though, it probably won’t solve the problem because it’s hard to get the frothy bubbles to escape through the tube.
Add anti-frothing agent
With a tube inserted into the animal’s stomach, pour an anti-foaming agent down the tube. Something like linseed oil or turpentine can work, or if you have access to some of the newer products like “Bloateze”.
As a final emergency measure, you can stab a hole into the cow’s rumen to release the gas. This is a high risk procedure and should only be done if death is imminent. There are a number of problems that come with stabbing, including the risk of death from infection. This should be avoided if at all possible, but if there are no other options and the animal is certain to die, stab it. The hole should be made by stabbing with a sharp knife on the animal’s upper left flank, into the distended rumen. Once the knife is inserted, twist it to make the opening wider. This should cause stomach contents to start pouring out and relieve the pressure. This is a very traumatic procedure. It should only be done as a last life saving measure, and you should contact a vet afterward to advise on long term treatment.
In summary, yes: clover can kill cattle because it can cause frothy bloat to build up in the rumen. This can be prevented by understanding how the bloat is caused and managing your cattle’s diet accordingly. When it can’t be prevented, several measures can be taken to save the life of an animal that’s suffering from bloat.