Browsing by Author "Pitkonen, Mirjami"

The aim of this study was to investigate the effects of blue lupin supplementation on rumen fermentation and milk production responses of cows fed grass silage diets. The study was conducted at Viikki research farm of the University of Helsinki in spring 2013. In the experiment, eight multiparous Ayrshire cows were used, and four of them were fitted with rumen fistula. The average days in milk was 111 (± 29,3). The experiment was conducted as duplicated 4 × 4 Latin squares. The treatments used were four supplementary protein concentrates: control (without protein supplement), rapeseed meal, rapeseed/blue lupin mixture and lupin meal. The protein concentrates were prepared to contain isonitrogenous amounts of protein. Concentrates were fed at a rate of 12 kg/day and grass silage was fed ad libitum. Protein supplementation increased dry matter (DM) intake and milk production. Replacement of rapeseed meal with blue lupin reduced DM intake and milk production. Cows on protein supplemented diets had higher energy corrected milk yield than cows on control diet. Milk fat composition was lower with protein supplemented diets than control diet. Replacement of rapeseed meal with blue lupin meal increased milk fat concentration in milk. Milk urea and rumen ammonia concentrations were higher in protein supplemented than control diet. Rumen ammonia concentration also increased when rapeseed meal replaced blue lupin. Protein supplementation increased concentration of volatile fatty acids in the rumen fluid. Milk fatty acids were less saturated and contained more mono- and polyunsaturated fatty acids on protein supplemented diets than control diet. Replacement of rapeseed with blue lupin reduced concentration of polyunsaturated fatty acids in milk. Feeding mixture of rapeseed and lupin meal reduced concentration of polyunsaturated fatty acids when compared with the average of rapeseed or lupin meal. In protein supplemented diets, palmitic acid (C16:0) in milk was significantly lower and stearic acid (C18:0) significantly higher than on control diet. Conjugated linoleic acid (CLA cis-9, trans-11) content increased with protein supplemented diet, but replacing rapeseed meal with lupin reduced it. When rapeseed was replaced with blue lupin a linolenic acid (C18:3n-3) content was decreased. There were not any big differences in milk fatty acid composition between the diets supplemented with lupin or rapeseed meal. This study showed that blue lupin can be used as protein supplement for dairy cows, but milk production responses are not as good as with rapeseed meal.