Effects Of TMR Mixing Time And Alfalfa Hay Addition On Dry Matter Intake, Chewing Activity And Performance Of Lactating Dairy Cows

TMR technology is widely used over the past decade with the rapid development of Chinadairy industry. TMR mixing time have a significant effect on particle size of dairy diets, manydomestic and foreign studies have shown that dietary particle size, especially the particle sizeof roughage, had an effect on cows dry matter intake, rumination and digestibility of nutrientsto some extent, but for the appropriate particle size of the dairy diets, the study did not obtaina consistent result. Adding appropriate alfalfa hay in dairy cow diets can help to improve themilk yield, increase milk fat percentage, maintain the health of cows, and reduce the incidenceof metabolic diseases, but the price of alfalfa hay in the international market continued to risein recent years, it is necessary to handle well the relationship between dairy production andcost in actual dairy production, the study about alfalfa hay appropriate addition has a certainacademic and economic value.Experiment1was conducted to study the influence of different TMR mixing time on drymatter intake, chewing activity and performance in dairy cows, which was used to determinethe appropriate particle size and TMR mixing time in large-scale dairy farms of Shandongprovince; Experiment2was conducted to study the influence of diets containing differentalfalfa hay addition on dry matter intake and performance in dairy cows, which was used todetermine the appropriate alfalfa hay addition in large-scale dairy farms of Shandongprovince. Both of the experiments was expected to provide technical guidance for Scientificfeeding and management in dairy farms.In Experiment1, four multiparous and mid-lactation Holstein dairy cows were randomlyassigned to a4×4Latin square. Treatments were four diets of different TMR mixing time:Treatments1(mixing time of Alfalfa hay:12min, mixing time of Leymus chinensis:20min),Treatments2(mixing time of Alfalfa hay:9min, mixing time of Leymus chinensis:15min),Treatments3(mixing time of Alfalfa hay:6min, mixing time of Leymus chinensis:10min),Treatments4(mixing time of Alfalfa hay:3min, mixing time of Leymus chinensis:5min).Experiment period were19d in duration (14d of treatment adaptation and5d of datacollection), Monitoring system were used to measure Chewing activity from the16th day tothe17th day of the experiment period, total fences and urine were collected to evaluate thetotal-tract apparent digestibility and N balance from the18th day to the19th day of theexperiment period. The results indicated: compared with Treatment3and Treatment4,total-tract apparent digestibility and NDF digestibility was higher for Treatment1andTreatment2(p<0.05); compared with Treatment4, the ratio of fecal N and N intake was lower for Treatment1and Treatment2(p<0.05);fecal N and the ratio of total N loss and N intaketended to be higher among Treatments(0.05<p<0.1).Intake of DM, OM, peNDF, NDF,N didnot differ for cows fed diets of different mixing time(p>0.05);Milk yield,milkcomposition(milk fat, milk protein, milk lactose), milk composition(milk fat, milk protein,milk lactose)yield did not differ for cows fed diets of different mixing time(p>0.05); nosignificant difference were detected on chewing activity caused by diets of different mixingtime(p>0.05).In Experiment2, four multiparous and mid-lactation Holstein dairy cows were randomlyassigned to a4×4Latin square. Treatments were four basal diets (Alfalfa hay addiction:3,4,5,6kilogram) with the same NEL, IDCP and. proportion of forage to concentrate.Experiment period were19d in duration (14d of treatment adaptation and5d of datacollection), total fences and urine were collected to evaluate the total-tract apparentdigestibility and N balance from the18th day to the19th day of the experiment period. Theresults indicated: Milk yield was affected by Treatments (p<0.05),compared with Treatment1and Treatment4,Milk yield was higher for Treatment2; compared with Treatment1, Milkyield was higher for Treatment3; compared with Treatment1, milk protein percentage tendedto be higher for Treatment4(0.05<p<0.1); compared with Treatment1, milk proteinproduction tended to be higher for Treatment2and Treatment3(0.05<p<0.1); compared withother treatments, total protein concentration in Plasma before the morning feeding was higherfor Treatment1(p<0.05); compared with Treatment4,urea concentration in Plasma after themorning feed(6h) tended to be increased for Treatment3(0.05<p<0.1); compared withTreatment1and Treatment4, Propionate acid concentration in Plasma after the morningfeed(6h) tended to be higher for d Treatment2(0.05<p<0.1).Intake, total-tract apparentdigestibility of DM, OM, NDF,N did not differ for cows fed diets of different Alfalfa hayaddition(p>0.05); Energy metabolism did not differ for cows fed diets of different Alfalfa hayaddition(p>0.05); no significant difference were detected on Acetic acid, butyric acid, volatilefatty acids (VFA) concentration, the ratio of acetic acid and Propionate acid caused amongtreatments(p>0.05)The study shows that: under the experimental conditions, the suitable parrticle size of rationcould be:the percentages in dry matter>19mm、8-19mm、1.2-8mm and<1.2mm were45.20%、25.50%、16.55%�'�12.75%,respectively, the suitable TMR mixing time for Alfalfa hay andLeymus chinensis were9min and15min, respectively.The suitable Alfalfa hay addition formultiparous cows (Milk Yield:30Kg) fed corn silage as the main roughage were4kilograms.