不同牧草品种对体外发酵产气特性的影响

采用改进的体外产气技术评价了10种不同牧草的体外产气特性.利用非线性回归方程获得了Gompertz模型的发酵动力学参数(理论最大产气量、产气速率常数和延滞时间),分析了不同品种牧草间发酵动力学参数的差异及发酵动力学参数与营养成分之间的相关关系.结果表明,不同品种牧草间产气动力学参数差异显著(P<0.05).理论最大产气量、产气速率常数和产气延滞时间分别以苏丹草、黑麦草和桂牧1号最高,而以鲁梅克斯、鲁梅克斯和苏丹草最低.相关分析表明理论最大产气量和累积产气量分别与OM含量、NDS/CP值及(NDS-Ash)/CP值呈极显著正相关关系(P<0.001),而与CP含量呈极显著负相关关系(P<0.01).产气速率常数与营养成分无显著相关性.产气延滞时间与半纤维素的含量呈极显著正相关关系(P<0.01),而与NDS/CP值和(NDS-Ash)/CP值呈极显著负相关关系(P<0.001).结论认为牧草中非结构性碳水化合物与蛋白质比例决定了体外发酵产气的特性.     

Effect of monensin and vitamin E on milk production and composition of lactating dairy cows

Feeding unsaturated oils to lactating dairy cows impair ruminal biohydrogenation (BH) of unsaturated fatty acids (USFA) and increase ruminal outflow of BH intermediates such as trans‐10, cis‐12 CLA that are considered to be potent inhibitors of milk fat synthesis. Supplementing lactating dairy cow’s rations containing plant origin oils with monensin and/or vitamin E may minimise the formation of trans‐10 isomers in the rumen, thereby preventing milk fat depression. Therefore, this study was conducted to evaluate the effects of monensin and vitamin E supplementation in the diets of lactating dairy cows containing whole cottonseed, as the main source of FA on feed intake, milk production and composition, milk fatty acid profile, efficiency of nitrogen (N) utilisation, efficiency of net energy (NE) utilisation and nutrients digestibilities. Four multiparous Holstein lactating dairy cows (86 ± 41 days in milk) were assigned to a balanced 4 × 4 Latin square design. Each experimental period lasted 21 days with a 14 days of treatment adaptation and a 7 days of data collection. The control diet was a total mixed ration (TMR) consisted of 430 g/kg forage and 570 g/kg of a concentrate mixture on dry matter (DM) basis. Cows were randomly assigned to one of the four dietary treatments including control diet (C), control diet supplemented with 150 mg of vitamin E/kg of DM (E), control diet supplemented with 24 mg of monensin/kg of DM (M) and control diet supplemented with 150 mg of vitamin E and 24 mg of monensin/kg of DM (EM). Dry matter intake (DMI) ranged from 19.1 to 19.5 kg/d and was similar among the dietary treatments. Dietary supplementation with vitamin E or monensin had no effect on milk production, milk fat, protein and lactose concentrations, efficiency of utilisation of nitrogen and net energy for lactation (NE_L). Digestibility of DM, organic matter (OM), crude protein (CP) and ether extract (EE) was not affected by the dietary treatments. Digestibility of neutral detergent fibre (NDF) was higher in cows fed with the M and EM diets in relation to those fed the C and E diets. The concentrations of C4:0, C6:0, C8:0, C10:0, C12:0, C14:0, C15:0, trans‐10‐16:1, cis‐9‐16:1, 17:0, 18:0, trans‐11‐18:1, cis‐9‐18:1, cis‐9, trans‐11 conjugated linoleic acid (CLA), trans‐10, cis‐12 CLA, and 18:3n‐3 FA in milk fat were not affected by the dietary supplementations. While feeding the M diet tended to decrease milk fat concentration of C16:0, the milk fat concentration of C18:2n‐6 FA tended to be increased. Dietary supplementation with vitamin E or monensin had no effect on milk fat concentrations of saturated, unsaturated, monounsaturated, polyunsaturated, short chain and long chain FA, but feeding the M diet numerically decreased milk fat concentration of medium chain fatty acids (MCFA). The results showed that vitamin E and/or monensin supplementations did not improve milk fat content and did not minimise the formation of trans‐10 FA isomers in the rumen when whole cottonseed was included in the diet as the main source of fatty acids.     

Effect of wood kraft pulp feed on digestibility,ruminal characteristics,and milk production performance in lactating dairy cows

The effect of wood kraft pulp (KP) feed on dietary digestibility, ruminal fluid pH, rumen fermentation characteristics, and milk production performance in lactating dairy cows was examined. Four lactating dairy cows were used for the feeding experiment by the cross‐over design. The control group and KP group were set up as treatments. The control group was fed total mixed ration (TMR) (40% roughage and 60% concentrate) and the KP group was fed TMR containing 12% KP that replaced half of the rolled corn in the control diet. The dry matter intake, digestibility of the feed components, and milk yield were not significantly different between control group and KP group. The number of times that the ruminal fluid pH was below 6.1 tended to decrease in the KP group compared to the control group (p < 0.10). The acetic acid ratio in the ruminal fluid of the KP group increased compared to the control group (p < 0.05) and the propionic acid ratio in the ruminal fluid of the KP group decreased compared to the control group (p < 0.05). The acetate:propionate acid ratio was increased in the KP group compared with the control group (p < 0.05). Lipopolysaccharide levels in the ruminal fluid of the KP group tended to decrease compared to the control group (p < 0.10). Based on these results, it was indicated that the use of KP feed for lactating dairy cows induced the same rumen fermentation characteristics as those in cows given a large amount of roughage without depressing milk productivity. Therefore, KP could be a valuable feed resource substitute for grains, which would also reduce the risk for subacute rumen acidosis.     

Effects of ear corn silage supplementation on milk production and milk fatty acid profiles in grazing dairy farms

This study investigated the effects of substituting ear corn silage (ECS) for commercial formula feed on milk production and milk fatty acid profiles in grazing dairy farms during the summer season. A field survey was conducted on five grazing dairy farms in every summer month of 2017, 2018, and 2019. Three of the five farms substituted fresh ECS for the commercial formula feed at a ratio of 2:1 from July of each year (ECS farms). Other farms maintained the same feeding management as before (non‐ECS farms). An interview survey was conducted on each farm to calculate feed intake and milk yield per cow. Feed and milk samples were collected in each survey. Milk compositions and milk fatty acid profiles were determined. The substitution of ECS for the commercial formula feed did not affect milk yield or milk composition, but ECS farms maintained low levels of milk urea compared with non‐ECS farms (p < .01). The ECS substitution also influenced some of the milk fatty acid proportions; C16:0 and C16:1 increased, and trans‐11 C18:1, cis‐9,trans‐11 C18:2, and the sum of polyunsaturated fatty acids decreased, while these fatty acid proportions were maintained in non‐ECS farms throughout the summer season (p < .05).     

不同微生态制剂对奶牛产奶性能和乳品质的影响

[目的]研究旨在探讨不同微生态制剂对奶牛产奶性能和乳品质的影响,[方法]将40头荷斯坦奶牛随机分成4个处理组,对照组饲喂基础日粮,微生态制剂1组、微生态制剂2组、微生态制剂3组分别在基础日粮中添加0.1%的三种微生态制剂产品。[结果]结果显示：与对照组相比,微生态制剂1组、微生态制剂2组、微生态制剂3组的平均日产奶量、乳蛋白率均显著增加（P＜0.05）,体细胞数均显著降低（P＜0.05）。与对照组相比,微生态制剂1组的平均日采食量、乳脂率均显著增加（P＜0.05）,料奶比显著降低（P＜0.05）。与微生态制剂2组相比,微生态制剂1组的平均日产奶量、乳蛋白率均显著增加（P＜0.05）。[结论]说明三种微生态制剂产品均能在一定程度上提高奶牛的产奶性能和乳品质,以微生态制剂产品1的作用效果最好。     

亚急性瘤胃酸中毒耐受性不同的奶牛血浆和乳中脂肪酸及代谢物组成分析

The present study aimed to explore the differences in plasma and milk metabolism of dairy cows with different subacute rumen acidosis (SARA) tolerance. Twelve fistulated Holstein dairy cows in mid lactation[days in milk=(114±22) d] were selected and fed the same diet consisting of 60% forage and 40% concentrate mixture. On days 20 and 21 of the trial period, the rumen pH was monitored at 0, 2, 4, 6, 8, and 12 h after morning feeding. Milk samples were collected before feeding in the morning and evening. Blood samples were collected from the jugular vein 6 h after morning feeding. All the milk and blood samples were stored in liquid nitrogen for subsequent fatty acid composition and metabolome analysis. Cows with the lowest and highest ruminal pH were assigned into the susceptible (SUS, n=4) and tolerant (TOL, n=4) groups, respectively. The fatty acid composition results showed that the proportions of ≤C16 fatty acids in the blood and milk were significantly increased in the SUS group (P< 0.05), while the proportions of > C16 fatty acids were significantly decreased (P< 0.05). The levels of the saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) in the milk were significantly decreased in the SUS group (P< 0.05). The LC-MS metabolomics results revealed that the L-phenylpyruvate was significantly reduced, while the levels of remaining MG (18: 0/0: 0/0: 0), 9-HODE, niacinamide, isovalerylcarnitine, phosphocreatine, L-glutamic acid, and 12(13) Ep-9-KODE were substantially increased in the SUS group. The results of milk metabolome analysis indicated that the levels of 1-stearoylphosphoglycerolserine and sphingosine were significantly increased, while the levels of 14 different metabolites were significantly decreased in the SUS group (P< 0.05), including glyceryl-phosphoryl-ethanolamine, glycerol 3-phosphate, and orotic acid. These differential metabolites were mainly involved in glycerophospholipid metabolism (P< 0.05), glycerolipid metabolism, and pantothenate and CoA biosynthesis. In conclusion, the fatty acids and metabolic profiles in the plasma and milk of cows with different tolerance to SARA were different. For the SUS group, the amino acid metabolism and the de novo synthesis ability of milk fat was enhanced in the plasma, while the ability to absorb long chain fatty acids from blood was weakened. At the same time, the levels of phospholipid, orotic acid and other nutrients were decreased in the milk, which indicated that the quality of milk was reduced for the SUS cows. © 2021, Editorial Office of Acta Prataculturae Sinica. All rights reserved.     

Milk yield,gross composition and fatty acid profile of dual‐purpose Aosta Red Pied cows fed separate concentrate‐forage versus total mixed ration

This study was designed to evaluate the effects of two feeding methods on milk yield, composition and fatty acid (FA) profile obtained from dual‐purpose cattle. Twenty‐four Aosta Red Pied cows beyond peak of lactation were assigned to two groups and fed hay and concentrates in the proportions 0.69 and 0.31 on a dry matter basis for 10 weeks. Concentrates were offered separately from forages 6 times a day (separate ration, SR) or as a total mixed ration (TMR). The feeding method did not significantly influence dry matter intake (16.8 vs. 16.9 kg/head/day for SR‐ and TMR‐fed cows, respectively), milk yield (17.4 vs. 17.5 kg/head/day), milk fat, protein and lactose contents (36.4 vs. 35.2, 33.5 vs. 32.8, and 47.3 vs. 47.4 g/kg) and yields (607.9 vs. 613.4, 567.4 vs. 572.7 and 805.5 vs. 829.7 g/head/day). The overall milk FA profile was very similar between groups. Milk concentrations of FA used as indirect markers of rumen function (C18:2 t10c12, odd‐ and branched‐chain FA) and the extent of ruminal biohydrogenation were comparable (P > 0.05) between SR‐ and TMR‐fed cows, suggesting that ruminal pH did not vary considerably as a consequence of the feeding strategy applied.     

Effect of anthocyanin‐rich corn silage on digestibility,milk production and plasma enzyme activities in lactating dairy cows

Anthocyanin in purple corn (Zea mays L.) has been reported to show several functional and biological attributes, displaying antioxidant, antiobesity and antidiabetic effects in monogastric animals. The objective of this study was to investigate the effect of feeding anthocyanin‐rich corn (Zea mays L., Choko C922) silage on digestibility, milk production and plasma enzyme activities in lactating dairy cows. The cows were fed diets based on the control corn or the anthocyanin‐rich corn silage (AR treatment) in a crossover design. The anthocyanin‐rich corn silage‐based diet had a lower starch content, nutrient digestibility and total digestible nutrients content when compared to the control diet. The milk yield, lactose and solids‐not‐fat contents in the AR‐treatment cows were lower than in the control cows. The feeding of the anthocyanin‐rich corn silage led to a reduction in aspartate aminotransferase (AST) activity and an increase in superoxide dismutase (SOD) activity in the plasma. These data suggest that the anthocyanin‐rich corn has a lowering effect on AST activity with concomitant enhancement of SOD activity in lactating dairy cows. However, a new variety of anthocyanin‐rich corn with good nutritional value is needed for practical use as a ruminant feed.     

Effect of brewer's grain on rumen fermentation, milk production and milk composition in lactating dairy cows

Six lactating Holstein cows were divided into two groups (n = 3) and used in a double reversal trial with three periods of 14 days each to evaluate the rumen fermentation, milk production and milk composition of cows fed brewer's grain (BG). The control diets contained 14% chopped Sudangrass hay, 24% corn silage, 18% alfalfa hay cube, 34% concentrate mixture‐1 and 10% concentrate mixture‐2 (wheat bran, soybean meal and cottonseed). In the experimental diet, wet BG replaced the concentrate mixture‐2. The protozoal population, concentration of ammonia‐N and volatile fatty acids in the ruminal fluid did not differ between the control and BG diets. The molar percentage of acetic acid was significantly higher (P < 0.05) with the BG diet at 5 h after feeding. The milk yield, the percentage of protein, lactose, solids not‐fat and somatic cell counts of milk did not differ between the two diets. The percentage of milk fat tended to increase with the BG diet. The BG diet significantly increased the proportions of C18:0 and C18:1 in milk fat (P < 0.01, P < 0.05, respectively) and tended to increase that of conjugated linoleic acid.     

Effect of a non‐forage fiber of red bean hulls on ruminal mat characteristics,chewing activity and milk production in dairy cows

The evaluation of red bean hulls (RBH) as a non‐forage fiber source on ruminal mat formation, chewing activity and milk production was determined using two experiments. In experiment 1, four non‐lactating, rumen‐cannulated Holstein cows were offered a control diet of 60.1% forage, and an RBH diet of 51.6% forage and 9.4% RBH. Although the neutral detergent fiber (NDF) intake was higher with the RBH diet than the control diet, the physically effective NDF (peNDF) intake was lower. The rumination period tended to be longer with the RBH diet than with the control diet and the ruminal mat was formed even when the RBH diet was consumed. Ruminal fermentation parameters were not affected by treatment. In experiment 2, 40 lactating cows were fed a control diet of 53.4% forage or an RBH diet of 50.3% forage and 8.1% RBH. Dry matter intake, chewing activity and milk production were not affected by diet. Cows sorted against NDF in the control diet, but not in the RBH diet. It is concluded that normal ruminal function can be maintained because the ruminal mat was stratified and rumination activity was not reduced even when a low peNDF diet that contained RBH was given to dairy cows.     

Effects of substituting kraft pulp with corn silage on dry matter intake,ruminal mat formation,rumen fermentation,and rumination activity in non‐lactating cows

The present study examined the effects of substituting kraft pulp (KP) with corn silage (CS) on dry matter intake (DMI), ruminal mat and rumen fermentation characteristics, and rumination. Four non‐lactating, rumen‐cannulated Holstein cows were fed a CS diet comprising 36% grass silage (GS) and 64% CS or a KP diet comprising 36% GS, 57% KP, and 7% soybean meal. DMI was significantly lower in cows fed the KP diet than in those fed the CS diet (p < 0.05), whereas rumination time did not significantly differ between the treatments. Dry matter content in the rumen immediately before and 3 h after feeding was significantly higher in cows fed the KP diet than in those fed the CS diet (p < 0.05). The consistency and thickness of the ruminal mat did not significantly differ between the treatments. The ruminal mean retention time of feed particles tended to be longer in cows fed the KP diet than in those fed the CS diet (p < 0.10). The ruminal digestion rate of KP was comparable to that of GS and CS. Because ruminal mat was formed and rumination was stimulated, KP was considered to have the equivalent physical effectiveness as CS.     

Supplementary effect of peppermint (Mentha × piperita) on dry matter intake, digestibility, ruminal fermentation and milk production in early lactating dairy cows

The aim of this research was to investigate the effect of peppermint feeding on dry matter intake, nutrient digestibility, ruminal fermentation and milk production in early lactating cows. Four Holstein cows were offered a diet with 5% dried peppermint and four Holstein cows remained on a diet without 5% of dried peppermint on a dry matter basis. The addition of peppermint to feed did not affect dry matter intake, although the eating time of feed was increased by mixing the feed with peppermint. There were no significant differences in the nutrient digestibilities between the two treatments. The ruminal ammonia and volatile fatty acids concentrations were similar in the two treatments, however, peppermint ingestion by cows led to a decrease in ruminal pH. The lowered pH value was within the stable pH condition range. No significant differences in the treatments were observed in milk production or milk composition except for the milk fat content. These results suggest that feeding peppermint to early lactating cows had little effect on their dry matter intake, nutrient digestibility, ruminal fermentation and milk production.     

Effects of forage source and particle size on chewing activity,ruminal pH,and saliva secretion in lactating Holstein cows

The present study investigated the effects of dietary forage source (quality) and particle size on chewing activity, saliva secretion, and ruminal pH. Twelve multiparous lactating Holstein cows, four of which were ruminally cannulated, were used in a replicated 4 × 4 Latin square experimental design with a 2 × 2 factorial arrangement of treatments. Cows fed wild‐rye hay diets had longer daily eating times than cows fed oaten hay diets. Treatments had no effect on ruminating time; therefore, resting time varied inversely to eating time. Neither the rate nor the amount of saliva secretion while eating, ruminating, or resting was affected by diet, resulting in similar total daily saliva secretions across treatments (231 L/day). Total volatile fatty acids (VFAs) in the ruminal fluid from animals fed oaten hay diets were higher than those from animals fed wild‐rye hay diets; further, VFAs increased with decreasing forage particle size (FPS). Consistent with elevated VFA concentrations, reducing FPS and including oaten hay in the diet decreased mean ruminal pH and increased the daily time of ruminal pH under 5.8. Results of this study suggest that forage source and particle size affect ruminal pH might be via variations in VFA production rather than increased salivary recycling of buffering substrates.     

清热解暑中药验方对热应激奶牛采食行为及产奶性能的影响

本试验探讨3种清热解暑中药验方对热应激奶牛采食行为及产奶性能的影响.40头泌乳末期的中国荷斯坦奶牛随机分为4组,分别接受4种处理,即对照组、清热健胃组、清暑组和加减白虎汤组.所有试验牛饲喂相同的全混合日粮,3个处理组分别补饲清热健胃散、清暑散和加减白虎汤散剂,用量为每日每头150 g.结果发现,全天采食量和牛舍各时点的温度和温湿指数极显著负相关.在奶牛处于轻度热应激时添加清热解暑中药对采食行为影响不显著,仅在第1天早饲时略影响采食速度.清暑组干物质采食量较高,产奶量下降较少,表明清暑散具有缓解热应激、促进食欲的作用.     

Effects of a pantothenic acid supplementation to different rations on ruminal fermentation, nutrient flow at the duodenum, and on blood and milk variables of dairy cows

To investigate the effects of a dietary pantothenic acid (PA) supplementation on duodenal nutrient flows, blood and milk variables and especially on duodenal PA flows and PA concentrations in blood and milk German Holstein cows, equipped with cannulas in the dorsal sac of the rumen and in the proximal duodenum were used. In the first experiment of the study two dry and six lactating cows received a diet with a forage to concentrate (F:C) ratio of 34:66 (high concentrate, HC), whereas in the second experiment a diet with a F:C ratio of 66:34 (high forage, HF) was fed to four dry and five lactating cows. The cows received both rations with or without 1 g PA/day. By supplementing PA to the HC ration, the molar percentage of acetic acid increased, whereas the concentration of total short chain fatty acids, the efficiency of microbial protein synthesis in the rumen and the serum glucose levels, decreased. With the HF ration the PA decreased the molar percentage of propionic acid and increased the amount of ruminally fermented organic matter. Furthermore, PA supplementation only increased the duodenal PA flow with the HF ration, while the serum and milk PA concentrations and milk PA yields were not affected. Based on the results of the present study, a rumen-unprotected supplementation of PA makes no sense.     

Faecal characteristics and milk production of dairy cows in early-lactation fed diets differing in forage types in commercial herds

Effects of grass–clover silage (GCS) alone or combined with whole-crop cereal silage, maize silage (MS) or ensiled pressed sugar beet pulp (EPSB) on faecal characteristics and performance of early-lactation dairy cows were studied in 26 herds. Data were analysed with herd as the experimental unit and correlation coefficients among the variables were estimated. Feeding MS combined with GCS resulted in faeces of a firmer consistency (P?P?r?=?0.83, P?r?=??0.54, P?r?=?0.63, P?相似文献   

柑橘渣对奶牛泌乳性能、养分消化率及乳成分的影响

试验评估不同水平柑橘渣对奶牛泌乳性能、养分消化及乳成分的影响.将32头泌乳性能一致的奶牛随机分为4个组,每组4个重复,每个重复2头.对照组饲喂粗脂肪水平为3％的日粮,处理组分别饲喂粗脂肪水平为5.5％的日粮同时添加0 (T1)、5％(T2)和10％ (T3)柑橘渣.结果 显示,与对照组相比,处理组奶牛的粗脂肪摄入量、干...     

瘤胃保护共轭亚油酸和亚油酸对奶牛产奶性能的影响

选择健康、泌乳月份与产奶量相近的多胎荷斯坦泌乳牛20头,随机分成5组,每组4头,研究日粮中添加商业来源的瘤胃保护共轭亚油酸钙盐(Ca-CLA)同时添加自然来源亚油酸(葵花油)对奶牛生产性能的影响。试验期为52d。对照组基础日粮为60%粗饲料(苜蓿、羊草、青贮)和40%精料(以DM为基础),处理组在对照组日粮基础上分别添加Ca-CLA100g/d·头(CLA)、葵花油350g/d·头(Sunf);Ca-CLA100g/d·头 葵花油350g/d·头(CLA Sunf),Ca-CLA50g/d·头 葵花油175g/d·头(1/2CLA 1/2Sunf)。结果表明:在奶牛日粮中,单独添加自然来源亚油酸产奶量较对照组差异不显著(P>0.05),而单独添加共轭亚油酸钙盐或与自然来源亚油酸高低不同剂量添加产奶量较对照组都分别显著提高2.20%、9.95%、11.16%,无论单独添加自然来源亚油酸或Ca-CLA或二者以高低不同剂量同时添加,牛奶的乳脂率较对照组都分别显著降低15.0%,6.24%,21.74%,14.35%。总之,奶牛日粮中同时添加Ca-CLA和自然来源亚油酸能显著提高产奶量,降低乳脂率,并且,减少Ca-CLA的添加量同时添加自然来源亚油酸可以达到高剂量添加Ca-CLA相同的效果。     

Effects of fumaric acid on rumen fermentation,milk composition and metabolic parameters in lactating cows

The aim of this study was to determine the influence of fumaric acid (FA) on ruminal fermentation and its effects on the acid‐base balance of seven ruminally and duodenally fistulated multiparous German Holstein cows. The experiment was conducted in a change‐over design with three periods in which the animals were randomly arranged in one of three treatments: Control (C; without FA), 300 or 600 g FA per day. The diets consisted of 7.4 kg DM grass silage, 4.2 kg concentrate mixture and 0, 300 or 600 g FA or wheat starch as isocaloric compensation per day and cow. FA supplementation decreased the rumen pH, acetic acid and butyric acid and increased propionic acid in rumen fluid. The results of the single‐strand conformation polymorphism analysis (SSCP) did not show an influence of FA on the microbial population in the rumen. The beta‐hydroxybutyrate (BHB) concentration in blood and the pH of the urine decreased, while the blood gases were unaffected by supplementation of the acid. The microbial protein per MJ ME decreased in the duodenum with FA supplementation. The milk fat concentration decreased after addition of FA. We conclude that in this study feeding of up to 600 g FA per day did not result in an acidosis. It seems that up to 600 g FA per day did not have a significant influence on the acid‐base balance of dairy cows.