Keeping an Eye Out for Acidosis

We’ve all seen it: that one steer standing in the dry lot looking miserable, staring into nothingness with its head down like his fa-vorite football team just lost a national championship. A football disappointment would be a less costly diagnosis, but this case is likely acidosis.
Acidosis is the most commonly seen nutritional disorder on cattle operations. However, it can be prevented fairly easily with close monitoring through good bunk management practices, adequate water sources, and attention to feed grind and particle size.

“Acidosis is often the common denominator for many nutritional challenges on-farm,” explains Justin O’Flaherty, a nutrition analytic consultant for Rock River Laboratory. “Some producers assume sodium bicarbonate will fix their problems, but it is a relatively weak buffer, especially in high-grain diets.”

Acidosis occurs when a highly processed diet is fed, and when intake is not limited. The rumen pH drops, causing decreased rumination. In turn, less saliva is produced, reducing buffering capacity. The rumen pH of animals consuming forages is generally between 6.5 – 7, while the rumen pH of animals consuming grain is generally 5.6 – 6.2. When cattle become acidotic, their rumen pH falls to 5.0 – 5.8 for a prolonged period of time, which can cause irreparable damage to the rumen papillae. These papillae are important for absorbing Volatile Fatty Acids (VFAs).

To prevent acidosis, rather than the expensive challenge of identifying and treating it after the fact, O’Flaherty offers a few producer tips:

Manage the bunk
Bunk management is the most important factor in trying to prevent acidosis in cattle. O’Flaherty recommends feeding twice a day — ideally at the same time every day. Using a bunk scoring system can help keep an eye on cattle and aid with feed efficiency.

“I cannot over-emphasize the importance of walking feed bunks and identifying feed refusals,” says O’Flaherty. “Growing up with a feedlot nutritionist father, we were always taught to use a stair-stepping method. If cattle left feed in the bunk on Thursday, we would bump their feed down a little on Friday. If they cleaned up all of their feed on Friday, we would bump them back up and give them a little more on Saturday.” Creating consistency in feed intake can increase feed efficiencies and gains while decreasing the risk of acidosis.

Dial in feed and forage intake
Avoiding overeating hay is just as important as avoiding overeating grain. Round bales are considered free choice and not ideal. “If you must use a round bale, turn cattle in with the bale for 15 minutes and then restrict their access,” says O’Flaherty.

She goes on, “cleaning up feed refusals is essential, as is making sure cattle don’t have feed in front of them 24 hours a day.” Not only can this strategy improve intake efficiency, and thus average daily gains, but it also helps cattle avoid engorgement – and thus acidosis.

Increase grind size
“A common problem I observe in small operations is grain-based feed with too small of a grind,” states O’Flaherty. “Processed feed, especially grains, should not look like chicken feed.” The safest grinding goal O’Flaherty recommends for dry corn is splitting the kernel in half, or quarters. This offers a wide range of particle sizes for bacterial attachment and digestion over a longer period of time.

“I would recommend not putting a screen in a grinder,” states O’Flaherty. “If you are unsure of your particle size, a lab analysis can help you determine the proper grind size for your operation’s needs.”

Get serious about water variables
“The rumen contents are 88% water, so when water intake decreases, so does feed consumption,” says O’Flaherty. “For every one pound of dry matter intake cattle need seven pounds of water.”

Water temperature can also play a role in acidosis prevention. O’Flaherty recommends keeping water in the optimal temperature range for rumen functionality. “As the rumen functions at 102 degrees Fahrenheit, the ideal water temperature is between 40 and 60 degrees Fahrenheit. Any water consumed at a higher or lower temperature than that range can slow digestion or reduce intake.”

Analyze for total dissolved solids
Be aware of total dissolved solids in the water. If not observed, these pieces of sediment in water can wreak havoc on cattle. “A rate of over 5,000 parts per million of total dissolved solids can kill cattle as it settles in the rumen, essentially plugging it,” says O’Flaherty. “Testing water for this every six months is a good idea – especially during hot weather, as the cattle will tend to spend most of their day in ponds.”

Identifying acidosis can be difficult for some. Bloat, lack of feed consumption, weakness and listlessness, occasional kicking at the belly, and grey manure are all symptoms of acidosis and a veterinarian should be consulted as soon as any of these indications are observed. Even if caught early and the affected animal survives, longstanding health problems are still likely.

While these risks for acidosis are abundant, they can be curbed and prevented. Cattle managers should make sure to avoid acidosis if at all possible, as the associated costs add up quickly. Good management and prevention can make or break an operation, so may the rumen pH and your cattle’s gains be ever in your favor!

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