The Assembly amended the Gujarat Animal Preservation Act, 1954, in the absence of the Opposition members, who had been suspended for the day, as several saffron-clad priests watched from the visitors' gallery.
Chief minister Vijay Rupani expressed his pride, tweeting: "The Gujarat Assembly passed a cow protection bill, among d most stringent in d country, making cow slaughter a life time punishable offense."
In 2011, then chief minister Narendra Modi's government had amended the 1954 law to raise the maximum sentence for cow slaughter from three years to seven and the maximum fine from Rs 50,000 to Rs 5 lakh.
Today's amendment fixed a minimum for the fine: Rs 1 lakh.
It also made the punishment stricter for transporting beef or beef products in any form, raising it from a maximum three years to one between seven and 10 years. The fine remains identical to that for cow slaughter.
Any vehicle used to ferry beef will be permanently seized.
The amendment comes months ahead of the Gujarat Assembly elections, due at the year-end. Fresh from the spectacular performance in Uttar Pradesh, party president Amit Shah, who visited Gujarat over the past two days, is eyeing 150 seats in a House of 182.
Rupani, elevated as chief minister less than a year ago, has made harsher cow protection laws a key agenda of the government, talking about it in several public speeches as the elections draw nearer.
Congress spokesperson Shaktisinh Gohil, a former leader of the Opposition in the Assembly, described the amendment as "vote bank politics, triggered by the BJP's poor showing in the local body elections".
He said the BJP was interested not in protecting cows but only in staying in power, at the cost of polarising the voters.
"If the BJP were genuinely interested in cow protection, why have successive BJP governments done away with the subsidies provided to cow shelters by previous Congress governments?" Gohil asked.
"Why have they endangered the lives of cows by selling grassland to industrialists to create what they call 'Vibrant Gujarat'?"
Asked why the Opposition was suspended before the bill was put to vote, Gohil said this had been standard practice in the "Gujarat model of democracy" since the Modi years.
"They create some provocation that agitates the Opposition. When we protest, they suspend us," he said.
Legislating against cow slaughter at the national level has been a pet project of the Sangh parivar. Some historians believe it has been an unfinished agenda even for the Congress conservatives since B.R. Ambedkar, head drafter of the Constitution, styled it a directive principle rather than a fundamental right.
Only eight states, mostly in the Northeast besides Bengal and Kerala, allow unrestricted cow slaughter in practice. All others have some form of restriction, and the BJP's ascendancy has put the slaughter and consumption of even buffalo meat at risk.