Effects Of Roughage On Chewing Behavior And Rumen Internal Environment In Lactating Dairy Cows

The diets of lactating dairy cows need a certain amount of fiber to maintain normal rumen internal environment and prevent the decrease in milk fat, but the source of dietary has different effect on rumen internal environment. Thus, the nutritional value of dietary fiber is a problem for dairy nutrition science. The concept of pe NDF has received increasing attention because it amalgamates information on both chemical fiber content and particle size of feedstuffs. but the concept of pe NDF still has obvious deficiency. Thus, the experiment was conducted to study the effects of roughage level, source and length on chewing behavior and rumen internal environment in lactating dairy cows.The effects of dietary roughage level on chewing behavior and rumen internal environment in lactating dairy cows. Twelve multiparous Holstein cows in mid-lactation were randomly allocated to 4 treatments in a triplicated 4×4 Latin square experiment with one cow in each treatment surgically fitted with rumen cannula. Treatments were varied dietary roughage levels, which were 40, 50, 60, or 70% on DM basis for the four treatments respectively.Results indicated: Increasing with dietary roughage level, DM, CP, OM, and NEL intake decreased, ADF intake increased, milk yield decreased. Intake of NDF was quite stable across treatments(7.79 to 8.05 kg/d/cow). Daily eating time increased linearly, the number of meal was quite stable(8.30 to 8.50 times/day). Ruminating time was increased to a near tendency and had no significant effects on both ruminating periods and chewing time per period. Total chewing time expressed as time per kg of ADF intake was similar across treatments and was183.53 min per kg of ADF intake. Total VFA concentration and molar percentage of propionate in ruminal fluid were decreased linearly. Eating saliva secretion increased linearly,ruminating saliva secretion was increased to a near tendency level, resting saliva secretionwas decreased to a near tendency level, but the total saliva secretion was not affected by treatments.The effects of roughage source on chewing behavior and rumen internal environment in lactating cows. Twelve multiparous Holstein cows in mid-lactation were randomly allocated to 4 treatments in a triplicated 4×4 Latin square experiment with one cow in each treatment surgically fitted with rumen cannula. Four treatments were : 0%, 30% or 60% of alfalfa hay and oaten hay was replaced with soyhulls and 60% and 40% of alfalfa hay and oaten hay was replaced with soyhulls and wildrye hay. Results indicated, increasing with the level of replacement: Dietary DM, NDF, ADF, CP and NEL intake were increased, dietary pe NDF>4mm and pe NDF>8mm intake significantly reduced, the intake of DM and other nutriments in 60%group did not significant difference with 60%+wildrye hay. The yield of milk production,4%FCM, milk fat and milk lactose did not significantly difference, the content of protein increased significantly. The yield of milk protein in 60% group did not significantly difference. The eating time was decreased, rumination time was not difference, total chewing time was decreased. The eating and ruminating time of 60% group were not difference with60%+wildrye hay. The number of eating meals and rumination periods did not significantly difference. The ruminal p H was decreased, the time of ruminal p H<5.8 was increased. The ruminal p H of 60%+wildrye group higher than 60% group, the time of ruminal p H<5.8 was decreased. Total VFA and acids concentration were increased, the VFA and acids cocentration of 60%+wildrye hay group was not significantly difference. The eating and rumination saliva secretion did not significantly affect, but the resting saliva secretion was increased, but total saliva secretion did not significant affect. The saliva secretion of60%+wildrye hay group were not significant difference with 60% group.The effects of roughage source and length on chewing behavior and rumen internal environment. Twelve multiparous Holstein cows in mid-lactation were randomly allocated to4 treatments in a triplicated 4×4 Latin square experiment with one cow in each treatment surgically fitted with rumen cannula. Treatments were long oaten hay, short oaten hay, long wildrye hay and short wildrye hay on DM basis. Results indicated: The source of roughage did not affect on DMI, but the NDF intake of wildrye hay was higher than oaten hay, the reduced in roughage length increased the intake of DM and NDF. The nutriments total tract apparent digestibility of oaten hay were higher than wildrye hay. The yield of milk production,4%FCM, fat, protein and TS in wildrye hay group was lower significantly than oaten hay. The eating and total chewing time of oaten hay were lower than wildrye hay, the reduced in length of roughage significantly lowed the eating and total chewing time. The rumination time was not affected by roughage source and length. The meals of eating and periods of rumination did not significantly affect. The mean, minimum and maxmimum ruminal p H oaten hay group were significant lower than wildrye hay group, the reduced in length of roughage significantly decreased the mean, minimum and maxmimum ruminal p H. The area and time of ruminal p H< 5.8 of oaten hay group were significant higher than wildrye hay group, the reduced in length of roughage significantly increased the area and time of ruminal p H<5.8. The concentration of total VFA, propionate and butyrate in oaten hay group were significantly higher than wildrye hay group, the reduced in roughage length increased the concentration of total VFA and butyrate. The eating, ruminating, resting and total saliva secretion were not significantly affect by the source and length of roughage.In conclusion, the level, source and length of roughage did not significantly affect on total saliva secretion, dietary roughage increased saliva production may be not the determinant of regulating rumen acidity, rumen acidity may be determine by fermentability of nutrients in the diet.