The effect of the periodic feeding of linseed oil on the production and iodine value of milk fat

Abstract

SummaryA study was made of the changes in the iodine value of milk fat from cows following the feeding of linseed oil (450g) at intervals of 6 days. Three cows in midlactation and of differing age and breed were used. The experiment consisted of a series of 3 collection periods, each of 6 days' duration, with 12 days between periods. Three doses of oil were given (6 days apart) between periods 1 and 2, the last dose of oil being given immediately before the start of period 2. The mean iodine values for the 3 periods were 35·5, 40·5 and 34·7 respectively. There was a distinct pattern of change in iodine value with time after feeding the oil, a maximum of 45·5 being attained on the second day with a subsequent decline to 38·5 on the sixth day. Analysis of variance showed that these effects were significant and due to oil-feeding, whereas changes in yield and content of fat and production of milk could be accounted for by normal decline in lactation. It was concluded that the periodic feeding of a large dose of linseed oil produces a significant increase in the iodine value of milk fat and avoids the possible disadvantages of continuous fat supplementation.