Abstract #W118

# W118
Responses in performance and feed intake of early-lactation dairy cows supplemented with linseed oil coated with vegetable fat or extruded linseed.
J. M. Ruiz-Rodriguez1, M. Puyalto2, J. J. Mallo2, G. Elcoso3, A. Bach*4,5, 1Department of Agrarian Production. Polytechnic University of Madrid, Madrid, Spain, 2Norel S.A, Madrid, Spain, 3Blanca from the Pyrenees, Hostalets de Tost, Spain, 4Department of Ruminant Production, IRTA, Barcelona, Spain, 5Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain.

The aim of the study was to evaluate the effects of supplementing extruded linseed or linseed oil coated with hydrogenated palm fatty acid distillates (HPFAD) on DMI and milk yield of early-lactation dairy cows. Sixty-three Holstein cows (591 ± 84 kg BW, 42 ± 24.8 DIM, 37.2 ± 10.6 kg of milk/d) were randomly distributed in 3 groups (n = 21) and exposed for 84 d to 3 treatments following a complete randomized design. Treatments consisted of supplementation with 500 g/d of HPFAD (CTR), 350 g/d of extruded linseed and 390 g/d of HPFAD (EXT), or 500 g/d of HPFAD coated linseed oil (HFL). Both, HFL and EXT diets provided the same amount of linolenic acid. Cows were fed a TMR (15.5% CP, 33.7% NDF, 1.65Mcal of NEl/kg; DM basis) twice daily. On a daily basis, BW, DMI, milk yield, and milk fat and protein contents were determined individually. Animal was the experimental unit and data were analyzed using a mixed-effects model for repeated measures. Feed intake was lower (P < 0.01) in HFL (22.8 ± 0.54 kg/d) than in CTR (24.9 ± 0.54 kg/d) or EXT (25.7 ± 0.54 kg/d) cows, and it was affected by an interaction (P < 0.01) between treatment and time due to a lower increase in DMI in HFL as the study progressed. Milk yield and milk protein content did not differ among treatments. Milk fat content (P = 0.02) was lower in EXT (3.33 ± 0.06%) compared with CTR (3.55 ± 0.06%) cows, with HFL cows (3.36 ± 0.06%) not differing with either treatment. Milk fat yield (P < 0.01) and ECM (P = 0.02) were affected by an interaction between treatment, week and parity with multiparous cows on CTR producing more fat and ECM at the beginning of the study and multiparous cows on HFL producing more fat and ECM toward the end. As a result, feed efficiency (ECM/DMI) was greatest (P < 0.01) in HFL (1.83 ± 0.04), with no differences between CTR (1.63 ± 0.04) and EXT (1.66 ± 0.04) cows. Although HFL cows had a lower DMI, yield performance and BW were not affected along the study. We conclude that HFL has the potential to improve FE through a decrease in DMI while sustaining milking performance.

Key Words: linseed, linolenic acid, palm fatty acid distillates