Effect of Chromium Propionate Substituting 25% Rumen-protected Choline on Production Performance and Blood Indicators of Perinatal Dairy Cows

The object of this study was to investigate the effects of chromium propionate replacing 25%rumen-protected choline(RPC)on production performance and blood indicators of perinatal dairy cows.According to the principle of ensuring that chromium propionate and RPC were fed 14 days prepartum,27 healthy Holstein cows(age,parity,lactation volume,body condition and expectancy were similar)were randomly divided into three groups(GroupsⅠ,ⅡandⅢ),with nine cows in each group.Cows in GroupⅠwere fed basal diets;cows in GroupⅡwere fed the same basal diets with 10 g•d-1 RPC per cow;and cows in GroupⅢwere fed the same basal diets,but 7.5 g RPC and 2.5 g chromium propionate(4 mg chromium)per cow.The results showed that dry matter intake(DMI)of prepartum in GroupsⅡandⅢwas significantly increased(P<0.05),compared with GroupⅠ;however,there was no significant difference between GroupsⅡandⅢ(P>0.05).The milk fat content in GroupⅢwas significantly higher than that in GroupⅠon the 7th day of postpartum(P<0.05).The urea nitrogen content in GroupsⅡandⅢsignificantly lower than that in GroupⅠon the 21st day of postpartum(P<0.05),but there were no significant difference between GroupsⅡandⅢ(P>0.05).The somatic cell counts in GroupⅢwere significantly lower than those in GroupsⅠandⅡon the 14th and 21st days of postpartum(P<0.05).The contents of the total cholesterol in GroupⅢdecreased significantly compared to GroupⅡon the 7th day of prepartum,on the day of calving and the 7th day of postpartum(P<0.05).The concentration of high-density lipoprotein(HDL)in GroupⅢwas significantly higher than that in GroupⅡon the 7th day of prepartum,on the day of calving and the 7th day of postpartum(P<0.05).On the 7th day of postpartum the concentration of insulin in GroupⅢwas obviously higher than that in GroupⅡ(P<0.05).In summary,replacing 25%of rumen-protected choline with chromium propionate reduced production costs and improved dairy farming benefits.

Effects of Rumen-protected Methionine on Rumen Fermentation, lactation Performance and Plasma Characteristics in Dairy Cows

The objective was to evaluate effects of rumen-protected methionine （RP-Met） supplementation on rumen fermentation, lactation performance and plasma characteristics in dairy cows. Twenty-four multiparous （2.2 - 0.40 parity） Holstein dairy cows, averaged 620 ± 12.3 kg of BW, 68 ± 2.5 day in milk and daily milk production averaged 26.0 ±0.3 kg/cow were used in a replicated 4 × 4 Latin square experiment. The treatments were： control （without RP-Met）, LRP-Met, MRP-Met and HRP-Met with 20, 40 and 60 g RP-Met per cow per day, respectively. RP-Met was hand-mixed into the top one-third of the daily ration. Experimental periods were 30 days with 15 d of adaptation and 15 d of sampling. Dry matter （DM） intake and milk yields were not affected （P 〉 0.05） with increasing RP-Met supplementation. Yields of 4%FCM, ECM, milk fat and milk protein were higher （P 〈 0.03） for RP-Met supplementation than control and were quadratically （P 〈 0.05） changed due to the higher percentage of milk fat and protein for RP-Met supplementation than control （P 〈 0.03）. Ruminal pH tended to be lower （P = 0.071） for RP-Met supplementation than control, whereas total VFA concentration tended to be higher （P = 0.086） for RP-Met supplementation than control. Ratio of acetate to propionate decreased linearly （P = 0.001） from 4.01 to 3.57 as RP-Met supplementation increased due to the increase in propionate production. Digestibilities of DM, OM, CP, NDF and ADF in the total tract were higher （P 〈 0.05） for RP-Met supplementation than control and were quadratically （P 〈 0.05） increased with increasing RP-Met supplementation. Plasma concentrations of glucose not affected （P 〉 0.05） with RP-Met supplementation, Plasma concentrations of non-esterified fatty acids （NEFA） were significantly lower （P = 0.017） for RP-Met supplementation than control and were linearly （P = 0.011） changed. Plasma concentrations of beta-hydroxybutyrate tended to be lower （P = 0.068） for RP-Met supplementation than control and were linearly （P = 0.001） changed. The present results indicate that supplementation of diet with RP-Met improved the content of milk fat and protein, rumen fermentation and feed digestion, decreased plasma concentrations of NEFA. It was suggested that the RP-Met stimulated the digestive microorganisms or enzymes in a dose-dependent manner. In the experimental conditions of this trial, the optimum RP-Met dose was about 25 g RP-Met per cow per day.

Rumen-protected lysine supplementation improved amino acid balance,nitrogen utilization and altered hindgut microbiota of dairy cows

This study was conducted to evaluate the effects of dietary crude protein(CP)and rumen-protected lysine(RPL)supplementation on lactation performance,amino acid(AA)balance,nitrogen(N)utilization and hindgut microbiota in dairy cows.Treatments were in a 2×2 factorial arrangement,and the main effects were CP concentration(16%vs.18%)and RPL supplementation(with or without RPL at40 g/cow per day).Forty cows were randomly allocated to 4 groups:low-CP diet(LP),low-CP diet plus RPL(LPL),high-CP diet(HP),high-CP diet plus RPL(HPL).The experiment was conducted for 8 weeks.Results showed that RPL increased the dry matter intake(P<0.01),milk protein yield(P=0.04)and energy corrected milk(P=0.04),and tended to increase milk fat yield(P=0.06)and fat corrected milk(P=0.05).Cows in the HP group tended to have higher milk urea N(P=0.07).Plasma concentrations of Arg,Ile,Lys,Met,Pro,total essential AA and total nonessential AA were increased by RPL(P<0.05).The total essential AA,total nonessential AA and most AA(except Ile,Phe,Gly and Pro)were increased in the HP group(P<0.05).N excretion was increased in the HP group through an increase in urea N excretion(P<0.01)and an upward trend in plasma urea N(P=0.07).In addition,RPL tended to increase milk protein N secretion(P=0.08),milk N(P=0.07)and microbial protein synthesis(P=0.06),and decreased plasma urea N(P<0.001).In the hindgut,the bacterial community were different between the LP and LPL groups(P<0.01).The probiotic abundances of Christensenellaceae_R-7_group and Acinetobacter were increased by RPL(P=0.03 and 0.03,respectively).The pathogenic abundances of Clostridium_sensu_stricto_1(P<0.001)and Turicibacter(P<0.01)were decreased by RPL.In conclusion,supplementing RPL with low dietary CP could balance AA supply and increase milk protein yield,resulting in an improvement in N utilization efficiency,and altered the composition of the hindgut microbiota to favor the lactation performance of dairy cows.

Rumen-protected glucose supplementation in transition dairy cows shifts fermentation patterns and enhances mucosal immunity

Manipulation of perinatal diets,such as supplementing feed with rumen-protected glucose(RPG),has been positively regarded as a strategy to improve milking performance.This study was conducted to assess the effects of RPG on the fermentation profiles,resident microbiota and mucosal immunity in the cecum.Ten Holstein dairy cows were randomly assigned to either a 25 g/kg RPG diet(DM basis)or a 11 g/kg coating fat diet(control,CON).Compared with the CON group,the acetate-to-propionate ratio was lower in the RPG group.Gene expression analysis indicated that RPG supplementation tended to upregulate the expression of Na^(+)/H^(+)hydrogen exchanger 3(NHE3)(P=0.076).RPG supplementation downregulated the expression of genes involved in self-rehabilitation such as matrix metalloproteinase 1(MMP1),MMP3,MMP9 and MMP13.Additionally,the mRNA expression of genes involved in immunity including Toll-like receptors(TLR4,TLR6 and TLR7)and proinflammatory cytokines(immune interferon gamma[IFNG]and interleukins interleukin 17 A[IL7 F],IL17 A,IL22),was downregulated by RPG supplementation.Nonetheless,no differences existed in the bacterial copy number and beta diversity between the 2 groups.Overall,supplementation with RPG would probably cause a shift towards propionate production in the cecal digesta,and promote the immune homeostasis of the cecal mucosa in transition dairy cows.Our results extended the basic understanding of RPG supplementation and utilization in transition dairy cows in terms of host microbe interplay in the cecum.

Analytical Evaluation of Omega 3 Fatty Acids Imbedded in Hydrophobic Starch in the Rumen

Two experiments were conducted to assess the value of hydrophobic starch as a method to encapsulate a supplement consisting of refined fish oil intended for use as a feed supplement for ruminant animals. In Study 1, the product was incubated in vitro for 24 hours. The entire media was analyzed to determine fatty acid composition. In Study 2, the test material was incubated for 0, 2, 4, 6, 8, 10, 12 and 24 hours in order to determine rate of loss of dry matter, as well as the fatty acid profile of the dry matter remaining at 24 hours. Results from Study 1 indicated that 61.1 % of the eicosapentaenoic acid (C20:5) and 75.3% docosahexaenoic acid (C22:6) were still intact after the 24 hour incubation period. In Study 2, 39.1% of the test material was solubilized in the 24 hour period. However, the losses in C20:5 and C22:6 fatty acids were less (25.32% and 27.90% respectively) indicating that the majority of the test product was protected against biohydrogenation. It was concluded that hydrophobic starch can be used to ruminally protected fish oil and to deliver C20:5 and C22:6 fatty acids past the rumen.