Dimethyl sulfide in milk of lactating dairy cows fed various sulfur compounds

Mature dairy cows in late lactation were given capsules containing 26, 40, 60, or 80 g of D,L-methionine; 32, 49, 69, or 90 g of methionine hydroxy analog; or 1, 2, or 4 ml of dimethyl sulfide. Animals used as controls received capsules containing water. Milk was collected at hourly intervals for 5 h and analyzed for dimethyl sulfide content by gas chromatography. All experimental cows were managed and fed (mainly corn silage plus concentrate with some hay and pasture) with the rest of the herd but were limited to water and clover hay during the 5-h experimental periods. Administration of 60 or 80 g of D,L-methionine or 1, 2, or 4 ml of dimethyl sulfide resulted in the appearance of dimethyl sulfide in the milk. The concentration of dimethyl sulfide in milk from cows receiving orally administered dimethyl sulfide (2 or 4 ml) was greatest at 1 h. When D,L-methionine (60 or 80 g) was given, dimethyl sulfide concentrations were lower and peaked later in the sampling period. The maximum concentration of dimethyl sulfide in the milk was 4.5 ppb when 4 ml of dimethyl sulfide were administered orally. No dimethyl sulfide was in the milk for any amount of methionine hydroxy analog, for 26 or 40 g of D,L-methionine, or for control capsules.