Effects of using different levels of flaxseed in dairy cattle diet on milk fatty acid profile

The purpose of this study was to determine the effects of using different levels of flaxseed in dairy cattle diet on performance, milk fatty acid profile and some blood and rumen parameters. For this purpose 9 lactating Holstein cows in the similar parity and lactation day were used. This study was designed as 3 period, 3 treatment groups and 3 cows in each group with crossover design. Each period lasted 21 days, of which 14 days was adaptation period and 7 days was data collection period. During the experiment 2 different concentrate feeds were used and corn silage, dry vetch grass, wet sugar beet pulp and straw were used as roughages. Feeds were prepared as total mixed ration. Cows in control group, 1st and 2nd treatment groups received a diet containing 0, 250 and 500 grams of flaxseed, respectively. Inclusion of flaxseed in the diets did not affect dry matter intake, milk yield, feed conversion ratio and milk fat, milk lactose and milk urea nitrogen. However it increased omega-3 fatty acids in milk and decreased the ratio of omega-6 to omega-3 fatty acids. Inclusion of flaxseed in the diets did not affect rumen pH, ammonia nitrogen, urea nitrogen and fecal dry matter of groups. Cows receiving 250 g/d flaxseed had higher izovaleric acid content and concentration in rumen. Inclusion of flaxseed in diet did not affect blood biochemical parameters. Results showed that using different levels of flaxseed in the diets increased omega-3 fatty acids in milk without negatively affecting performance, milk fat, blood and rumen parameters and thus it can be used in producing functional milk.