A series of articles on improving cow milk production are quite disturbing to me. To begin with, there is this one where the authors show that giving chilled water to cows produces an increment in the milk production (about a 5%). Wondering whether cows may not like it at all, the experimenters find out that "cows given a choice of chilled or warm water showed a clear preference (about 98%) for the warm water". For them, the obvious conclusion is that then "If cows are given chilled water of 10 degrees C continuously, no warm drinking water should be available". So much for the cows. A friend thinks that, anyway, the cost of chilling the water may be larger than the benefit produced by the extra-milk production.
If you don't care about cows' preferences, then there is this one were (please, excuse me my language) they feed cows with variable amounts of chicken shit (up to 17.4% of the total "food" intake). This was not affecting milk production, and much better, "no off flavors in milk could be attributed to processed poultry excreta added to feed". Well, this is something comforting! I wonder whether they just smelled the milk or if they really drank it. Now, if a disease can be transmitted by feeding animals with other processed animals, imagine what can happen if you make one eating the excrements from another.