Danish-Swedish dairy company Arla Foods late last year posted on social media that it was going to trial a cow-food additive on some of its U.K. farms aimed at reducing methane emissions in its herd.

Another spillover of the H5N1 bird flu virus from wild birds to dairy cattle appears to have occurred, this time in Arizona.

Until last week, all bird flu in dairy herds had been identified as the B3.13 variant, which was believed to have come from ...