Chrysanthemum Leucanthemum has also been suspected of imparting a bad flavour to butter.
According to Pott the milk of cows eating Oxalis Acetosella is with difficulty converted into butter.
The poisonous principle of Colchicum autumnale is stated to find its way into the milk of animals consuming it, and Müller states that the milk of goats which have eaten it has caused the poisoning of infants.
Müller states that a cat died after drinking the milk of a cow suffering from poisoning by Narthecium ossifragum.
Mercurialis annua is said to cause milk to be thin, “blue,” and poor in fat; while in a case already mentioned (p. [68]) M. perennis entirely stopped the secretion of milk.
According to Chesnut, goats may eat quantities of Euphorbia Lathyris, and it is said that their milk then possesses the poisonous properties of the plants. Ingestion of other Euphorbias appears to have the same effect.
Cornevin remarks that Melampyrum arvense is considered to influence cows to produce more milk.
According to some authorities species of Equisetum check milk production or cause it to cease, and E. palustre is stated by Weber to cause the milk of affected cows to become watery, poor in fat, and give rise to a greasy and unappetising butter, while the yield may soon quite fail.
The ingestion of the foliage of the oak (Quercus sp.) is stated by Cornevin to induce Maladie des Bois, with reduction or entire loss of milk production (see p. [69]). Acorns have also affected milk production, and a case is recorded (The Dairy, 1913) in which it is stated that cheese made from the milk of cows which had fed on acorns developed a sharp acid flavour when about four weeks old, though the texture was good. It is not clear, however, how it was proved to be due to the acorns.
In one case recorded a reddish tinge was observed in the milk of a cow suffering from Rhododendron poisoning (p. [46]), and in general reduced milk production appears to occur.