Effects Of Complex Probiotics On Milking Performance,Immune Function And Harmful Gas Emission In Manure Of Dairy Cattle

This study was conducted to investigate the effects of adding compound probiotics on rumen fermentation, milking performance, immune and antioxidative functions, intestinal flora and harmful gas emission in dairy cattle through in vivo and in vitro experiments, in order to provide a reference for scientific application of compound probiotics in dairy industry.In the first in vitro experiment, there were five treatment groups in which0(control group),0.1,0.2,0.3and0.4mL of probiotics agents were respectively added in artificial rumen flasks with a rubber plug and60mL artificial rumen fluid. Fermentation time is24h, after that artificial rumen fermentation parameters and greenhouse gas production were determined. The results showed that, with the increasing of probiotics additive, the pH of culture fluid increased linearly (P<0.001) or quadratically (P=0.001); nitrogen content also increased linearly (P=0.001) or quadratically (P=0.006); DM degradation rate showed a linear (P=0.014) or quadratic (P=0.048) increase; the gas production at24h showed a linear (P=0.033) increase. In addition, the CO2content decreased linearly (P=0.001) or quadratically (P=0.001).In the second in vitro experiment, two hundred grams of fresh feces were collected and mixed with0(control group),2%,4%and6%of probiotics respectively, and the mixture were placed in a flask covered with a rubber stopper and then incubated at a constant temperature for five days. During incubating, the amount of released ammonia was determined, and after incubating, other parameters such as ammonia nitrogen, total nitrogen and microorganism were analysed. The results showed that, with the increasing amounts of added compound probiotics, ammonia nitrogen content in cow dung showed significant linear (P=0.003) or quadratic (P=0.012) decrease. The total nitrogen content showed significant linear (P=0.002) or quadratic (P=0.010) increase. E. coli showed significant linear (P=0.002) or quadratic (P=0.008) decrease. Lactobacillus content showed significant linear (P=0,001) or quadratic (P=0.006) increase.Eighteen mid-lactation Australia Holstein cows with similar parity, body weight, lactation stage and milk yield were divided into three treatment groups and were fed with, respectively,0,50and100mL of compound probiotics per head every day in the feeding experiment. This experiment lasted for60days, during which the effects of compound probiotics on the milk yield, milk composition, somatic cell count, nutrient digestibility, immune indices, antioxidative index and the intestinal flora were determined. In addition, fresh cow manure was collected on day30and60in order to measure the NH3production after72h of fermentation. The results showed that feeding compound probiotics significantly improved the levels of milk lactose, milk fat, total solids, serum IgG, serum CAT and lactobacillus content in cow dung (P<0.05), while reduced significantly the somatic cell count (SCC) in milk and serum MDA. Throughout the trial period, supplementing compound probiotic significantly reduced the production of manure ammonia (P<0.05).These results suggest that the compound probiotics can change the rumen fermentation pattern, improve the milk production performance, immune and antioxidative function, adjust the intestinal micro ecology and improve the air quality in the barn.