Abstract
The study was carried out to investigate the effects of feeding sufflower oil protected from ruminal hydrogenation by encapsulation with formaldehyde-treated casein to cows (exp. 1) and fattening steers (exp. 2). In exp. 1, three Holstein cows, milking about 15kg per day, were fed twice daily the ration composed of 4kg timothy hay, 8kg beet pulp and 5-6kg customary concentrate feed. Cows were treated in the following order: 1) standard period, 2) encapsulated sufflower oil (CSO)-feeding period (at 100g per day), 3) non-treating period, 4) CSO-feeding period (at 300g per day), 5) non-treating period and 6) CSO-feeding period (at 600g per day). Fatty acid compositions of milk fat and plasma lipid were measured on the last day of each period consisting of five days. Results are summarized as follows: 1. There was a tendency for increased linoleic acid content in plasma lipid with the increase in the amount of CSO included in the ration. 2. Blood glucose increased with increasing CSO. 3. Linoleic acid content of milk also increased from almost negligible value in the standard period to 21.6% of the total acids determined when cows were given CSO at 600g per day. 4. Milk secretion and milk fat percentage increased in accordance with the feeding of CSO. In exp. 2, six Holstein steers, weighing over 550kg, were fed ad lib. concentrate and rice straw, and three of them were given CSO, which was mixed with the concentrate at the rate of 100g CSO per 10kg concentrate, for 37 days before slaughter. Results obtained are summarized as follows: 1. Linoleic acid content of plasma lipid increased significantly (p<.05) with CSO feeding, but the fatty acid composition of carcass fat was little influenced by CSO feeding. 2. Stearic acid level in kidney- and intraperitoneal adipose tissues was twice as high as that in subcutaneous adipose tissue and muscle (longissimus dorsi). Linoleic acid content of intramuscular lipid was about twofold that of the lipid of the other three adipose tissues. 3. The feeding of CSO exerted little influence on the body weight gain, feed conversion and the carcass quality of cattle under the present experimental conditions.
