Effect And Mechanism Of Saccharomyces Cerevisiae And Its Fermentation Products Supplementing On Peformance Of Dairy Cows During Perinatal And Early Lactation

The perinatal period of cows is characterized by the need for a large amount of energy for the synthesis and secretion of milk,but the negative energy balance caused by a serious lack of feed intake,and a large number of metabolic stress.All of these can lead to a decline in the body's immunity,which can easily cause diseases such as ketosis and mastitis,and reduce the production performance of cows in the next lactation cycle.Due to the huge consumption of labor,and to meet the needs of calves at the same time,colostrum lost a lot of energy,minerals and immune substances,leading to lower blood levels of calcium in pre-lactating dairy cows.Meanwhile,because of decreased appetite and decreased digestive function,these nutritional and immune elements are not timely supplemented,and their own milk production gradually increases.In order to improve the negative nutritional status of dairy cows,dairy cows mobilize body fat and body white to meet the needs of lactation,resulting in a decrease in body weight.Saccharomyces cerevisiae and its metabolites stimulate the ruminant microorganisms of ruminants,regulate microecological balance,and promote the growth of beneficial bacteria to achieve the purpose of improving production performance.Saccharomyces cerevisiae can also improve ruminal fermentation,increase feed digestibility and utilization efficiency,the number and viability of microorganisms,and enhance immunity.This experiment intends to explore the effect of probiotics(main components are Saccharomyces cerevisiae and their fermentation products)on the performance of perinatal and pre-lactating milk production and mechanism research through supplementary feeding.Experiment 1: To investigate the effect of Saccharomyces cerevisiae and its fermentation products on performance,blood hormone levels,and rumen flora of perinatal cows.60 perinatal cows were selected and divided into two groups based on parity and expected date.Each group was supplemented with 0 and 100 g of probiotics per head per day on the basis of equivalent TMR.The results showed that supplementation with Saccharomyces cerevisiae and its fermentation products could significantly increase the feed intake of perinatal cows(P<0.01),had no significant effect on the apparent digestibility of nutrients;increased lactose content 21 days postpartum,increased milk production The amount of the trend;can increase blood glucagon and ?-hydroxybutyric acid content,reduce insulin and growth hormone levels.It can significantly increase the content of acid and isovalerate in rumen fluid of dairy cows in perinatal period,and reduce the content of valerate.At the same time,supplementation with Saccharomyces cerevisiae and its fermentation products reduced the abundance of rumen microbes in periparturital dairy cows,but increased the content of Bacteroidetes.Experiment 2: Explore the effect of Saccharomyces cerevisiae and its fermentation products on the performance and blood hormone levels of pre-lactating cows.60 pre-lactating cows were selected and divided into two groups according to parity and milk yield.Each group was fed with 0 and 100 g of probiotics per head per day on the basis of equal amounts of TMR.The results of the trial showed that the supplementation of Saccharomyces cerevisiae and its fermentation products reduced milk protein content but increased the crude fat digestibility of pre-lactation cows,with no significant effect on milk production and feed intake.Supplementing Saccharomyces cerevisiae and its fermentation products can increase blood levels of glucagon,BHBA and leptin and reduce insulin and free fatty acid levels.And it can improve the content of isobutyric acid in rumen fluid of lactating cows.