Ruminal Acidosis (SARA) in Dairy Cattle: A Guide

Sub-acute ruminal acidosis (SARA) is a common, hidden problem in high-yielding dairy cows and buffaloes fed too much grain and too little fibre. It lowers rumen pH for hours each day, quietly reducing milk fat, appetite, fibre digestion and hoof health. It is largely preventable through better feeding management — balancing concentrate with enough good-quality fibre and rumen buffering.

What is ruminal acidosis?

The rumen works best at a near-neutral pH of about 6.0–6.5. When cows eat large amounts of rapidly fermentable starch (grain or cereal-based concentrate) with too little effective fibre, acids build up faster than they can be neutralised and rumen pH falls. Acute acidosis is a sudden, severe and sometimes fatal drop that needs emergency veterinary care. SARA is the milder but far more common form, in which pH stays below about 5.6 for several hours a day. Surveys estimate SARA affects roughly one in five early- and mid-lactation cows.

What causes SARA?

• High grain or concentrate and low forage in the ration
• Finely chopped or ground feed that reduces chewing and saliva — saliva is the cow's natural rumen buffer
• Sudden diet changes or feeding large concentrate meals at once ("slug feeding")
• Poor-quality or insufficient long fibre such as straw, hay or green fodder
• Wet, highly fermentable mixed rations without enough physically effective fibre

Warning signs on the farm

• A drop in milk fat percentage — often the first clue — and variable milk yield
• Reduced or choosy appetite; cows sorting their feed
• Loose, pasty or bubbly dung, sometimes with undigested grain
• Less cud-chewing (fewer than about 60% of resting cows chewing)
• Later: laminitis and lameness, poor body condition, liver abscesses and low fertility

How to prevent and manage SARA

Feeding management

• Keep an adequate forage-to-concentrate balance; never feed concentrate without enough fibre
• Offer good-quality long fibre (hay, straw, green fodder) to stimulate chewing and saliva
• Introduce concentrate gradually and split it across the day rather than in one large meal
• Avoid over-grinding feed; keep some "scratch factor" (physically effective fibre)
• Ensure constant access to clean drinking water

Rumen support

Rumen buffers such as sodium bicarbonate and good rumen-health practices help keep pH stable. Herbal digestive and rumen tonics can support appetite, cud-chewing and healthy rumen function as part of a balanced feeding programme — for example Ruminova, a rumen and digestive tonic, and Bloatgul Plus where gas and bloat accompany acidosis. To compare options, see our guide to the best digestive powder for cattle in India. Because SARA is a leading cause of milk-fat depression, it is also worth reading how to improve low milk fat and SNF.

Frequently asked questions

How is SARA different from bloat?

Both come from rumen fermentation problems, but bloat is a build-up of gas that swells the left flank and can be a sudden emergency, while SARA is a chronic drop in rumen pH that mainly shows up as low milk fat, loose dung and lameness over time.

Can acidosis be treated at home?

Mild cases improve by correcting the ration — more fibre, less rapidly fermentable grain, and a rumen buffer. Severe or sudden acidosis (a very sick, staggering or downer animal) is a veterinary emergency; call your vet immediately.

How do I know if my herd has SARA?

Watch herd-level clues: falling milk fat, loose dung with grain, reduced cud-chewing and unexplained lameness. If several cows show these signs, review the ration with your vet or animal nutritionist.

This article is for general educational purposes and does not replace professional veterinary advice. Always consult a qualified veterinarian or animal nutritionist. Cattle Remedies is a brand of Makams Industries Pvt. Ltd. References: NCBI/PubMed — Diagnosis and Management of SARA in Dairy Herds; NCBI/PubMed — SARA: causes, incidence and consequences.