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Graham Lawton is rightly concerned about the welfare of dairy cows ( 16 February, p 30 ). As an organic dairy farmer who, like most dairy farmers, is fond of my cows and has great compassion for them, I don't think we should be tarred with the same brush as those in other countries. In …

I found Lawton's article about the environmental and welfare impacts of the dairy industry very interesting, not least because it echoes my own beef with the industry. I was disappointed, though, that he limited discussion of the negative environmental impacts of cheese to its carbon footprint. I live in one of the driest regions of …

You report the suggestion of using CRISPR gene editing to limit the number of male calves ( 9 February, p 13 ). This is surely another example of agribusiness addressing the wrong problem. To produce milk, a cow must give birth every year. During her productive life, she could give birth to seven or eight …

Phew, it's only our descendants that will live in hell. We'll be alright Caroline responds to the possibility that Earth could warm by 14°C after 2100 as emissions destroy crucial clouds ( 2 March, p 10 )

Chelsea Whyte reports that an artificial intelligence system can diagnose childhood illnesses better than some doctors ( 16 February, p 19 ). Then we read that it is less effective than senior doctors. This makes it unsuitable for triage – deciding patients' priority for treatment – which should be done by the most senior clinicians, …

Petros Sekeris tries to see the Brexit omnishambles in terms of a two-player problem in game theory ( 16 February, p 24 ). This may not work, as there are more than two players on the UK side. Prime Minister Theresa May is playing against both the European Union and factions in her own political …

Those children protesting on the streets about the lack of progress in mitigating global warming are closer to making a difference than many people think (Leader, 23 February ). The UK is seeing the start of a political realignment, just as the US is seeing a shift to the left, and these are driven mainly …

You report research comparing the strength of the grip of married and single people ( 2 February, p 20 ). As someone who has happily avoided the conservative and historically religious structure of marriage, but has been in a committed relationship for over 20 years, I wonder where de facto couples stand in this type …

Teal Burrell reports a finding that people who exercise regularly lose little weight because they reduce energy expenditure when they aren't exercising ( 19 January, p 30 ). This is consistent with studies that colleagues and I conducted on energy expenditure and body composition in mice 30 to 40 years ago. We studied compounds that …

Public transport vehicles, running on specially defined routes in South Korea since 2010, pick up electrical power as they run ( 16 February, p 22 ). What a good idea. Could we not call them "trolley-buses"?