Thursday, 25 October 2012

Cow health: rumen disorders

(c) University of Minnesota
The rumen is a complex, large organ, which can hold up to 80 litres of feed. It is a sensitive organ, and any disturbances in the rumen can be lethal. Minor disturbances are quite common, and even some of the most severe cases can be solved at the farm without a vet. This text describes bloat (gas build-up in the rumen), "nail", acidic rumen and dislocation of the abomasum.

Bloat (the cumulation of gas or foam in the rumen)

The rumen contracts every 50-70 seconds, both mixing the feed and removing methane as belches. If these contractions stop or something blocks the esophagus, the gas keeps accumulating and filling up the rumen. When the rumen swells, it presses the cow's internal organs and lungs, blocking blood vessels and eventually suffocating the animal when the lungs no longer have space to expand.

(c) informedfarmers.com
Cause:  Gas can accumulate in the rumen for several reasons: the rumen stops contracting due to too low pH or nervous problems, the esophagus is blocked or the animal lies on it's side for too long. Foam can be created by the feed, often clovers or too much concentrated feed. The foam prevents the methane from being released as belches.

Symptoms: The cow's left flank swells considerably when the rumen fills with gas. The cow stops eating, and as the space for it's lungs decreases, it starts panting and gasping for breath. The condition can kill the animal in hours, depending on the severity.

Treatment: If there's foam in the rumen, the bubbles can be broken easily by giving the cow 5 desiliters of rapeseed or olive oil, or the same amount of melted butter. If the cow lies on it's side, it must be supported to the right position. Then find why the cow lies on it's side, and treat the root cause. If the rumen is swollen and the animal drools, the esophagus is blocked. The easiest way is to push the obstacle down the throat and into the rumen, thus freeing the esophagus.

Mild cases are often caused by changes in the nutrition, spoiled feed, ice cold drinking water or antibiotics given orally. In this case the cow has low appetite, and it may have pains and diarrhea. Mild cases can be treated with rumen supplements, dry hay, yeast and sugar (half a kilogram both)

An in-depth article about bloat in cattle by Alberta Agricultural and Rural Development

A sharp object in the fore-stomachs, "a nail"

Cows cannot select their feed as carefully as horses, so they may pick up and swallow foreign objects quite easily. Earlier the most common cause for this was a swallowed nail or a piece of barbwire, but luckily today those are more rare in the farms. Slaughterhouses constantly find foreign objects in the fore-stomachs: cell phones, scarves, wallets, scoops... Sometimes a coil of barbwire has fallen to the feed mill/feed wagon, got shred to small bits and been mixed with the feed, server to the whole cattle. Most often the cause is the carelessness of the people in the farm, leaving nails, hammers etc where to cows can reach them. Sometimes the animals can swallow foreign objects if they escape their pasture or barn.

Cause: When a foreign object is swallowed, it can either block the esophagus, get stuck in the digestive tract or pass through it. If the item is sharp, it may poke through the stomach walls, causing an infection. The item may become encapsulated in the digestive tract, whereupon tissue is grown around it, preventing the item from being removed or harming the organs. The reticulum is right next to a cow's heart. If a sharp object penetrates the reticulum wall, it may pierce through to the heart, causing a sudden death.

Symptoms: Symptoms vary based on the item swallowed and what it causes in the digestive tract. If the item is sharp and pierces any tissues, the animal shows signs of pain (restlessness, kicking of the abdomen). The cow may stand with it's back arched. Foreign objects in the esophagus or rumen may cause the animal to vomit, and in severe cases the cow will regurgitate even the water it drinks.

Treatment: If the foreign object is metal, the animal can be fed a magnet, which then stays in the rumen for the rest of the cow's life. The magnet catches any metal items, preventing them from pricking through the rumen walls. The animal should be tied to a stall, and it's front end should be raised. If the condition doesn't improve in 1-2 days, the foreign object must be removed surgically.
 

Acidic rumen

The pH of the rumen should always stay between 6-8. Sometimes if there's too much concentrated feed or not enough salive to buffer the contents, the pH of the rumen can drop quickly. Ruminants develop symptoms of acidic rumen when the rumen pH is lower than 5,5. Acidic rumen exposes the animal to problems with the abomasum, laminitis of the hoof, rumen wall damage and liver abscesses.

Cause: Too much starch and sugar in the feed cause very strong fermentation in the rumen, creating more acidic side products than the metabolism can handle. The feed may also require little chewing or ruminating. This condition offen occurs near calving, when the cow gets plenty of concentrated feed, but eats little roughage. Acidic rumen is also common with bulls to be slaughtered, since they are fed mostly concentrated feed.

Symptoms:  Loss of or variable appetite, wet feces, undigested feed in the feces, dropping of cuds (ruminated pieces of feed), mild bloat. The animal may lose body fat.

Treatment: Treating this condition once helps very little. Sodium bicarbonate (100-200 g / day) may relieve the worst symptoms, but the most important thing is to adjust the animal's diet to have enough hay or straw, and that the possible silage is not shredded too short. The diet must have only moderately starch and sugar, and they should not be given all at once. The animals must have access to clean water at all times.

Displaced abomasum

Abomasum is the last of the cow's stomachs, and the only which functions like the stomach of monogastric animals. As shown in the picture above, abomasum lies at the bottom of the abdomal cavity, behind the reticulum. Abomasum usually rises up to either side of the animal.
Picture adapted from The University of Missouri

Cause: The abomasum is displaced if its walls lose their tonus and the abomasum filled with gas. The cause is still uncertain, but high level of glucose and low level of calcium in the blood are contributing factors. Acidic rumen is also a risk, because it sends forward unfermented feed, which ferments even in the abomasum, creating gas and lifhting the abomasum up like a balloon. Stress and sickness near calving may also cause dislocation of the abomasum.

Symptoms: Loss of or variable appetite, no fever, slightly elevated levels of ketones. When pressing an ear against the animal's flank and tapping it with a finger, a distinct, metallic "ping" sound can be heard.

Treatment: Surgical treatment is the most effective, and can be done on-site. Gas is removed from the abomasum, and it is secured to its place with a few stitches. Another old remedy is to roll the cow over on it's back or making the animal run, but these provide often only temporary relief.


3 comments:

  1. This article has tonnes of information for those who have animal farms or dairy farms. I think a copy of it should be distributed among farms to let them know about rumen and how to avoid it and help your cow in staying happy and healthy.

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  2. nice blog !! i was looking for blogs related of animal feed supplement . then i found this blog, this is really nice and interested to read. thanks to author for sharing this type of information.
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  3. It is quite a technical article with biological information. Thanks for sharing such a useful information which i was not aware about it before.

    ReplyDelete