Yes, it is. Cow's methane is the biggest agricultural contributor to greenhouse gases.
Each year, a single cow will produce about 220 pounds of methane. Methane from cattle is shorter lived than carbon dioxide but 28 times more potent in warming the atmosphere, so the 220lbs of methane equal 6160lbs of CO2. A car produces 400g of CO2 per mile, so a cow damages the environment similarly to driving 7000miles. Since cows grow at least for 2 years before being slaughtered it will produce the equivalent of 14.000 miles of driving. A cow produces almost 900lbs of meat, so each pound of beef is like driving 15.5 miles.
Yes, the methane is that bad. Fossil methane is also bad but we need to halve methane emissions in the next 10 years or so to have a shot at keeping global warming to ~1.5-1.7c