Drankgivans och vallfoderkvaliténs effekt på konsumtion och produktion hos mjölkkor
The coproduct, dried distillers grains + solubles (DDGS) from ethanol production based on wheat contains much rumen degradable protein and fiber with low digestibility. To compliment this quality in an effective way a grass silage low in protein and much digestible fiber is needed.
The aim of the study was to investigate the effects of adjusting the crude-protein concentration and fiber quality of the silage when feeding DDGS and of varying the
inclusion level of DDGS, when feeding the adjusted grass silage, on intake, milk yield and composition, faecal traits and feed efficiency.
Four different total mixed rations were compared. The normal grass-clover silage had a crude protein content of 17,8 % and an NDF content of 46,2 % of dry matter. The adapted grass silage had a crude protein content of 14,6 % and an NDF content of 52,9 % of dry matter. The diets were formulated to have similar nutritional content except for A + 4 which had a higher content of rumen degradable crude protein and a lower concentration of NDF. The rations used were:
? Diet C+1: 1 kg of DDGS (4%) and standard grass-clover silage
? Diet A+1: 1 kg of DDGS (4%) and adapted grass silage
? Diet A+2,5: 2,5 kg of DDGS (10%) and adapted grass silage
? Diet A+4: 4 kg of DDGS (16%) and adapted grass silage
The experiment was conducted at Nötcenter Viken, using 48 dairy cows, that at the beginning of the trial had an average milk yield of 42.6 (±6,3) kg energy-corrected milk and averaged 106 ((±53,5) days in milk. The experimental design was a change-over experiment with four treatments and four periods of three weeks. Special feeding equipments were used to receive individual information about feed consumption from each cow. Feed consumption and milk yield were registered during the whole period of registration but milk for analysis of composition was registered during the last four days in each period. On the last day of each period, cows were scored for body condition and manure consistency and pH were registered. Faecal samples were later analysed by a wet sieving technique. All particles longer than 1 cm and all kernels were counted to evaluate rumen function of the cows.
All data concerning consumption, milk production and faecal characteristics were analysed with a mixed model in SAS vers. 9,1.
Results from the study show that feeding adaped grass silage instead of a standard grass-clover silage, with an inclusion level of 1 kg DDGS, increased intakes of rumen degradable fiber, decreased intake of INDF, and increased concentration and yield of milk protein, decreased milk urea content and improved feed efficiency (p