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Do cows still need buffers?

Elliot Block Published on 22 August 2014
cows at feed bunk

The inclusion of buffers in dairy rations is a well-researched and successful strategy. But buffers seem to have become a forgotten tool – or at the very least, one that’s taken for granted on many dairies today.

Yet neglecting this important part of dairy nutrition can have lasting impacts on cow health, rumen function and ration performance. If a cow’s rumen pH fluctuates to lower-than-desired levels, microbial yield and efficiency drops, dry matter intake declines and metabolic disorders can increase in relation to incidents of rumen acidosis – all of which one dairy recently discovered.

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Lagging performance

The owners of the 1,000-cow dairy were concerned their herd was not meeting its productivity potential.

Milk production hovered at 26,500 pounds, but milkfat levels seldom rose above 3.4 percent or 901 pounds of fat, and dry matter intake (DMI) was somewhat inconsistent, both on an individual basis and across pens. Stocking rate varied, but pens at 115 percent of capacity were not uncommon.

Furthermore, cows seemed to be bothered by various digestive and efficiency concerns – like inconsistent manure scores, signs of indigestion and subclinical acidosis, as well as a less-than-desirable feed conversion rate.

The challenges came on gradually and were easy to overlook, at least initially.

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Searching for answers

Once it became apparent that the herd had a problem, the herd manager and nutritionist began their search for the cause.

A look at the herd’s health records indicated a significant number of off-feed incidents, low rumination rates and cud-chewing activity and poor locomotion scores – along with other hoof health challenges.

A look at the ration also indicated that something wasn’t quite right.

The corn silage-based diet contained an adequate starch-to-fiber ratio, and microminerals and macrominerals were included at recommended levels. However, buffer inclusion rates were minimal – the diet contained only 0.25 pounds of buffer per cow per day and had drifted downward over time. Consequently, it took a while for the effects of this action to appear.

Research as far back as 1965 shows that buffers positively impact cow health and performance. And the recommended inclusion rate for sodium bicarbonate in lactating diets, for example, is 0.75 percent to 1 percent of TMR dry matter.

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The research on buffers over the years has been conducted with diets that were about 50-50 corn silage and haylage. This consideration carries increasing weight since increasing levels of high-quality corn silage is being fed than in past years.

Today’s diets include more fermentable carbohydrates – which require more buffering, not less. Rations also minimize fiber (physically effective NDF) and rely more on microbial protein and fermentation than in the past. In addition, variation in feed ingredient quality plays a significant role in ration performance.

Also, overcrowded facilities force cows to gorge or slug feed rather than eat small meals more often. This behavior frequently contributes to rumen acidosis.

The buffer answer

Given the recommended inclusion rates, a lactating cow eating 60 pounds of DM per day should receive at least 0.5 pounds of buffer per day.

The dairy increased the amount of ration buffer to this level and within months experienced fewer health incidents, improved rumination time, lowered laminitis incidence by 10 percentage points, and milkfat production consistently rose 0.2 percent.

Keep in mind the purpose of buffers is to smooth out the bouts of acidosis that cows will experience from time to time.

In addition, when buffer levels are fed at adequate levels, dairy producers will probably see more consistent dry matter intake and solids-corrected milk or energy-corrected milk production brought about by a better and healthier rumen environment.

This will likely not be an immediate and dramatic response. But you will see an improvement that can be measured over the course of a month or two. PD

References omitted due to space but are available upon request. Click here to email an editor.

PHOTO: Cows at feed bunk by PD staff.

Elliot Block
  • Elliot Block

  • Senior Manager of Technology
  • Arm & Hammer Animal Nutrition
  • Email Elliot Block

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