This past year has seen a sharp rise in Vitamin B1 (Thiamine) deficiency cases across New Zealand, particularly in Waikato herds. While this condition is most commonly observed in weaned calves, an unusual outbreak in November highlighted that adult cattle are also at risk under the right conditions.
In an autumn‑calving herd, the in‑shed feeding blend was adjusted at the end of October. Both Rumensin and Agolin were removed from the ration. Eleven days later, cows fitted with wearable monitoring technology began showing a sudden drop in rumination, signalling a developing issue.
Clinical signs progressed quickly. Affected cows became:
In other B1 deficiency cases, signs can also include:
head pressing, an arched neck, jaw champing, frothing at the mouth, seizures, and—in advanced stages—collapse and death.
Over a two‑month period, 60+ cows were affected and 8 died.
A post‑mortem confirmed Thiamine (B1) deficiency. Treatment was initiated immediately:
Thanks to rapid detection via rumination technology, cows showing early drops in rumination were drafted promptly and treated. Remarkably, most animals required only one injection, with no recurring symptoms.
Once Rumensin was reintroduced to the diet, new cases declined significantly within 10 days.
Cattle rely on rumen microbes to produce B1. Disruptions to that microbial population can lead to deficiency. Known triggers include:
B1 deficiency is typically seen in late spring and summer, and it can be easily confused with:
B1 deficiency causes swelling of the brain. Without intervention, increasing pressure leads to neuronal death. Because Vitamin B1 is rapidly excreted, typical treatment requires twice‑daily injections for at least 3 days. Steroids can help reduce swelling but were avoided here due to the risk of abortion in pregnant cows.
Most cows show improvement within 12 hours, with better alertness and steadier gait.
Oral B1 works well as a preventative during outbreaks but is less effective for urgent treatment.
If you’re ever unsure or see unusual neurological signs in cattle, get in touch — we’re always happy to help with the tricky cases.
Fun fact: Vision is often the last sense to return in animals recovering from B1 deficiency.
