Trakia University, Faculty of Agriculture, BG – 6000 Stara Zagora, Bulgaria
YILDIZ, E., 2015. Comparison of rations for dairy cows with soybean meal or with rapeseed meal in which the main source of protein is sunflower meal. Bulg. J. Agric. Sci., 21: 662–667
The aim of experiment is to check whether the inclusion of soybean meal in the diet will improve performance of dairy cows fed ration with sunflower meal as main protein source. This problem is important for East Europe and other regions where sunflower is the principal and cheapest protein source for ruminants. The trial is conducted with twenty four Holstein cows at 39 ± 10 days in milk in the beginning of the experiment, using the switch-back scheme. The cows were divided into two groups equalized by number of lactation, days in milk, milk yield in previous lactation, and last week before the experiment. They were fed rations with or without soybean meal for 4 weeks, and then rations were exchanged each for the other during another 4-week period. The first two weeks of each period of the trial were left for accommodation to the new ration and second two weeks - for collection of data for milk yield and composition. The cows in both groups were fed ad libitum with totally mixed rations. The two experimental rations contained approximately 2.5 kg alfalfa hay, 23 kg maize silage (32.35% dry matter and 19% grain in dry matter), 0.6 kg molasses and 11.5 kg concentrate mixture. The difference between the two experimental rations was in concentrate mixture composition. For the first ration concentrate mixture contained 12.7% soybean meal (SBM ration). In the concentrate for second ration, soybean meal and 5.9% of grain were replaced by 19% rape seed meal, canola type (RSM ration). The two concentrate mixtures contained 26% sunflower meal (SFM) (supplying 30% of crude protein /CP/ of the ration), and 8% dry distillers grain with soluble (DDGS) from maize (supplying 7.2% of total CP of ration). The two experimental rations were equal in feed units for milk (FUM = 6 MJ net energy for milk) and crude protein content. During each experimental period, as well as average for the two periods of trial, there were no significant differences (P > 0.05) in dry matter intake, milk yield, milk composition, as well as in dry matter and net energy (Feed units for milk) utilization for milk production, between rations. There was a tendency for higher live weight losses, and for bigger decrease in body condition score in cows receiving RSM ration. In conclusion under the conditions of the experiment, it is possible to replace, the expensive soybean meal with rapeseed meal, canola type in ration with sunflower meal as a main protein source.