TY - JOUR JO - Journal of Animal and Feed Sciences J2 - J. Anim. Feed Sci. SN - 1230-1388 VL - 22 IS - 4 PY - 2013 ID - Bettero2013 TI - Sources of omega-6 fatty acids do not alter the rumen degradation and transit of fibre from dairy cow diets AB - The objective of this study was to evaluate the behaviour of fibre in the digestive tract on the basis of the passage kinetics of forage and concentrate particles in cows fed different omega-6 fatty-acid sources. The scientific hypothesis of this study was that omega-6 fatty acids do not interfere with the digestion of fibre in the diets of dairy cows. Five primiparous lactating Holstein cows were used in the experiment. The experimental diets were: control (C), ground soyabean (GS), cottonseed (CS), soyabean oil (SO), calcium salts of fatty acids (CSFA). The global mean estimates for the parameters of passage rate ( γ ) were 0.038 and 0.055 h –1 for forage and concentrate, respectively. The only significant effect with respect to the passage rate was a high negative correlation between the concentrate passage rate and dry matter intake. There was less undegradable neutral detergent fibre (NDF) in treatments without added lipid. Dietary supplementation with lipid sources does not alter the kinetic parameters of roughage and concentrate particle passage or in vitro NDF degradation. Sources of omega-6 fatty acids do not alter the rumen degradation and transit of fibre. AU - Bettero, V. P. AU - Gandra, J. R. AU - Nunes, H. V. N. AU - Freitas Jr, J. E. AU - Barletta, R. V. AU - Carvalho, M. V. AU - Detmann, E. AU - Pereira, J. C. SP - 295 EP - 301 DA - 2013 DO - 10.22358/jafs/65916/2013 UR - https://doi.org/10.22358/jafs/65916/2013 ER -