Milk yield, composition, nutritive and technological values from ewes fed dried distillers’ wheat grains with solubles (DDGSw)
The aims of this study were to evaluate the effects of lactating dairy ewes diets supplementing with different vegetable protein sources (sunflower meal (SFM) vs. dried distillers? wheat grains with solubles (DDGSw)) at the pick of lactation (27 - 72 lactating day). The experiment was carried out with sixteen lactating dairy ewes, Bulgarian Dairy Synthetic Population (BDSP) in 60-d feeding trial (7-d preparatory + 45-d experimental + 8-d closing periods). Animals were allotted randomly (by age, lactation, milk yield, % milk fat, % milk protein) into two dietary treatments: 1./ a SFM- based control diet (CD), and 2./DDGSw-based experimental diet (ED). Diets were iso- nitrogenous, iso- fibrogenous, iso- caloric and equal in protein truly digestible in the small intestines (PDI), calcium (Ca) and phosphorus (P). Compared with the CD, supplementation with DDGSw decreased (p<0.001) the average daily milk yield (5.8 %) and 6.5 % fat-corrected milk (6.8 %). There?re no significant differences in milk composition between treatments (CD and ED): solids non-fat (SNF) + 0.8; dry matter (DM) + 0.1 %; fat content of milk (MF) - 1.1 and milk protein (MP) content + 0.4 % per sheep for ED, compared with CD. DDGSw- based diet did not affect nutritive and technological parameters of raw milk: MP/MF (+ 1.3 %), MP/DM (- 0.1 %) and MF/DM (- 1.0 %) ratios. In conclusion, observed data indicates that DDGSw at level of 17 % DM basis affected ewe milk yielding negatively, without affecting milk composition, nutritive and technological parameters.