Effect of source of nonstructural carbohydrates on performance of dairy cows fed sunflower seeds

Three studies were conducted to determine the effects of nonstructural carbohydrate (NSC) sources on performance of dairy cows fed sunflower seeds. In the first study, the effects of NSC source on dry matter (DM) intake, milk yield and milk fatty acid composition were evaluated using fifteen lactating Holstein cows in a 3 x 3 Latin square design. In the second study, fifteen lactating Holstein cows were used in a completely randomized design to determine the effects of NSC on the total tract nutrient utilization. The third study was designed to determine in situ ruminal degradability of DM, CP, NDF and starch of dietary treatments of study one and two, where two ruminally fistulated cows used in a randomized complete block design. Results of the in situ ruminal degradability trial showed that BC and CBC had similar effective ruminal degradability of DM and CP which was higher (P < 0.05) than that of CC. However, starch ruminal degradability was highest for BC, intermediate for CBC and lowest for CC. Sources of NSC had no effect on the NDF in situ ruminal degradability. It was concluded that changing the source of NSC and feeding sunflower seeds can modify milk fatty acid composition without any adverse effect on milk yield or milk components, and with no detrimental effect on nutrients utilization. (Abstract shortened by UMI.