The economic consequences of banning cow slaughter can be significant. It is quite likely that over time cows may disappear from India. A look at the data from livestock census, which is carried out every five years, is revealing.From 1997 to 2012 the number of cows has increased from 103 million to 117 million. Over the same time the number of male cattle has gone down from 96 million to 66 million.This is because tractors are replacing bullocks. The number of male cattle should be more or less the same as the number of cows if there is no slaughter. One could surmise that a large number of male cattle is being slaughtered or exported.The number of cows in milk has increased from 33 million to 42 million in this period. The proportion of crossbreed or exotic cows has increased from 15% to 25%. Thus the growth rate in milk production has been higher than that in the number of cows in milk.A cow gives milk after it has given birth to a calf. Thus the number of calves less than one-year-old should be equal to the number of cows in milk. One would expect that half of these would be females and half males as the probability of birth is roughly equal. As expected the number of female calves less than one year is around 50% of cows in milk. However the number of male calves is much smaller at around 35%. Presumably a significant number of male calves are either slaughtered or allowed to die soon after birth.Also a cow gives milk from age 3 to 10 years but lives for 20 to 25 years.Once a cow becomes unproductive, farmers sell it. Presumably the one who buys it slaughters it. This is seen in the number of cows that are not in productive age or calves. They constitute around 1-3% of the total number of cows. The number of male cattle above age 10 is around 2% of total male cattle. In the absence of slaughtering, their numbers should be around 50%.The ban on cow slaughter will affect the economics of the dairy industry. If the milk producer cannot get rid of an unproductive cow, she will have to feed it for the rest of her life. Since the unproductive cows will be as many as productive ones, the amount and cost of feed will double.This will increase the price of milk. In fact milk price will increase even more as the demand for feed will double and its price will be pushed up.This will also divert land to fodder production and less of other agricultural commodities will be produced. Their prices will also go up.In 2012, there were around 180 million heads of cattle. If the ban is effectively implemented all over the country, the number of cattle heads by 2027 will be around 360 to 400 million.They will put an enormous strain on the resources of the country. What however is likely to happen is that milk production from cows will be no longer competitive with milk production from buffaloes.No one would want to keep cows.Even bullocks used in farm operations will become expensive and would be replaced by tractors or working buffaloes. The ban on cow slaughter will result in a ban on cows. They may disappear from India. Of course if the government provides gaushalas for the unproductive cattle the dairy industry could still use cows for milk. But the price effect will still be there.If cow vigilantes continue to terrorise and murder people without any fear of punishment, as happened in Rajasthan on April 5, one can be sure that no one will want to keep any cows. Cows will be banished from India. In any case buffaloes produce more milk than cows. In 2013-14, of the 138 million tonnes of milk produced in the country 51% was from buffaloes, 20% from indigenous cows and 25% from exotic cross bred cows.The lynching of Mohammad Akhlaq by vigilantes for alleged consumption of beef at Dadri in 2015 also suggests that the ban on cow slaughter will affect India's meat production and meat and leather goods exports. While statistics for export of cattle beef is not available, data for export of beef including buffalo meat is. In FY2015 India exported 2.4 million tonnes of beef and veal according to the US Department of Agriculture, which classifies buffalo meat also as beef. India is the world's largest exporter of beef including buffalo meat.India's buffalo meat exports have been growing at an average of nearly 14% each year since 2011, fetching India as much as $4.8 billion in 2014.India now earns more from beef export than from export of basmati rice.It is thus very important that the ban on cow slaughter is carefully implemented in a way that does not discourage slaughter of buffaloes.(The writer is a former member of the Planning Commission)