Effects Of Increasing Amounts Of Different Dosage Of Perilla Oil Infused Into The Duodenum Of The Dairy Cows On The Oxidation Stability Of Milk

Two different experiments were composed of this thesis, which conducted to evaluate the effects of increasing different amounts of perilla oil infusate infused into the duodenum of the dairy cows and the change of storage condition on the profile of fatty acids and oxidatve stability of milk fat.Experiment 1: Effects of increasing low amounts of perilla oil infused into the duodenum of dairy cows on the oxidative stability of milk fatFour multiparous Holstein cows (BW = 556±19 kg, DIM = 93±9 day) that had been fitted with the duodenal cannula were administered the two treatments in a crossover design. After a 1-wk preliminary period in which cows were infused only with water, two cows received the control infusate and the other two cows received the perilla oil infusate. During this 5-wk experimental period (period 1), the two cows receiving the perilla oil infusate received each amount (0, 40, 80, 120 and 160 g/d) sequentially, with each amount continuous being infused for 7 day (20 to 22 h/d) before increasing to the next amount. During period 1, the two control cows received only the carrier infusate for the entire 5 wk. The objective of our experiment 1 was to observe the effect of infusion with increasing low amounts of perilla oil into the duodenum of dairy cows on the oxidative stability of milk fat.Results suggested that infusion with low perilla oil emulsion at varying amounts would change the profile of fatty acids, especially enhanced the content of n-3 PUFAs significantly in milk fat over the length of experiment, but decreased the oxidative stability of milk fat (the oxidative stability of the milk fat was not influenced by infusion with perilla oil between 0 and 80 g/d) Experiment 2: Effects of increasing high amounts of perilla oil infused into the duodenum of dairy cows and the change of storage condition on the oxidative stability of milk fatFour primiparity Holstein cows (BW = 476 kg±6 kg;DIM = 100±2 d) fitted with duodenal cannula were used in this experiment. The experiment design was similar to the experiment 1, but the dosage of infusion is different (0, 100, 200, 300 and 400 g/d). We collected the milk samples from the every amount of infusion dosage, determined the indices of oxidative stability with the experiment milk samples, in order to investigated the effects of increasing high amounts of perilla oil infused into the duodenum of the dairy cows on the oxidative stability of milk fat. And then put the milk samples stored in dark at either 4℃or 20℃for period of 0, 72, and 120 h to investigate the effect of storage condition on oxidative stability of the milk fat.Results suggest that infusion with high amounts of perilla oil emulsion at varying amounts would influence the fatty acid profile, but would decrease the oxidative stability of milk fat (the oxidative stability of the milk fat was not influenced by infusion with perilla oil between 0 and 100 g/d). And under five different storage conditions, the oxidation stability of milk samples were influenced by the fatty acid composition in milk fat.