牦牛乳及乳制品、犏牛和黑白花奶牛乳的脂肪酸组成分析

用气相色谱 质谱联用仪(GC MS)对牦牛乳、黑白花奶牛乳、犏牛乳及牦牛乳制品（奶油、酥油、曲拉、酸奶）中的脂肪酸组成进行了测定。结果表明,牦牛乳中功能性脂肪酸,如共轭亚油酸（CLA）、亚油酸（LA）、α 亚麻酸（ALA）、γ 亚麻酸（GLA）占总脂肪酸的比重均显著高于犏牛乳和黑白花奶牛乳（P＜0.05）;犏牛乳中ω 6/ω 3 PUFA的比值（1.55）略高于牦牛乳（1.54）,差异不显著（P＞0.05）,但都在最佳膳食平衡比值范围内,黑白花奶牛乳中ω 6/ω 3多不饱和脂肪酸（PUFA）的比值（11.33）超过了推荐最佳比值。加工处理能够改变乳制品脂肪酸的构成,如牦牛乳奶油中检测出原奶中所不含的一种亚油酸（18:2Δ8c,11c）。酥油主要以不饱和脂肪酸（UFA）为主,而曲拉主要以饱和脂肪酸（SFA）为主,牦牛酸奶中没有检测到GLA。     

乳及乳制品中皮革水解蛋白检测方法的研究进展

本文介绍了乳及乳制品中皮革水解蛋白的几种检测方法,主要包括比色法、氨基酸自动分析仪测定法、高效液相色谱法、高效液相色谱-质谱联用法、毛细管电泳法,并对各种方法的原理及其研究情况进行了详细阐述。     

复合益生菌制剂对奶牛泌乳性能及乳品质的影响

为研究复合益生菌制剂对奶牛泌乳性能及乳品质的影响,试验选取45头泌乳期相近的荷斯坦奶牛,随机分为3组,对照组、试验1组、试验2组,每组3个重复,每个重复5头。对照组饲喂基础日粮,试验1、2组分别在基础日粮中添加1%、2%的复合益生菌制剂,试验期为60d。结果表明:试验2组在第10、30、60天奶牛产奶量较对照组分别提高2.28%、0.62%、9.08%(P<0.05),试验1组在第10、60天较对照组分别提高4.6%、8.9%(P<0.05);第30天时,试验1、2组乳中总固形物含量较对照组均显著性提高(P<0.05),乳糖率、乳蛋白率、乳脂率之间差异不显著(P>0.05);第60天时,与对照组相比,试验1、2组乳中乳糖率分别提高了4.41%、7.02%(P<0.05),乳蛋白率提高了4.16%、9.97%(P<0.05),总固形物含量提高了2.44%、3.02%(P<0.05),乳脂率含量之间差异不显著(P>0.05)。综上,日粮中添加复合益生菌制剂可有效提高奶牛产奶量及乳品质,且添加2%复方益生菌制剂效果更优。     

不同粗饲料对奶牛乳产量和乳成分的影响

选择18头荷斯坦奶牛,设置3个处理,每个处理6个重复,每个重复1头奶牛,研究不同粗饲料对奶牛泌乳性能和乳成分的影响,3个处理的粗饲料分别为玉米秸(Ⅰ组)、玉米秸+青贮玉米秸(Ⅱ组)、羊草(Ⅲ组)。试验结果表明:①试验Ⅱ组与试验Ⅲ组平均产奶量差异不显著(P>0.05),试验全期分别比Ⅰ组提高了8.82%(P<0.05)和9.57%(P<0.05);②不同处理间的乳糖、乳脂含量差异不显著(P>0.05);对于乳蛋白,在试验40d时3个试验组差异不显著(P>0.05),在第15d时Ⅱ组、Ⅲ组分别比Ⅰ组降低了7.43%(P<0.05)和8.57%(P<0.05)。对于乳干物质,Ⅱ组与Ⅲ组差异不显著(P>0.05)。根据上述生产性能指标综合评定,玉米秸+青贮玉米秸可有效替代羊草饲喂奶牛,而不降低泌乳性能。     

植物甾醇对泌乳前期奶牛产奶量及乳成分的影响

根据年龄、胎次、泌乳时间和产奶量选择24头泌乳奶牛,随机分为对照组、试验Ⅰ组和试验Ⅱ组。对照组饲喂奶牛场配制的全混合饲料,试验Ⅰ和Ⅱ组每头奶牛日粮中分别添加40 g/d和80 g/d植物甾醇,研究植物甾醇对奶牛生产性能的影响。结果表明,与对照组相比,试验Ⅰ和Ⅱ组奶牛的产奶量分别提高了2.07 kg/d(5.64%,P0.05)和1.74 kg/d(4.75%,P0.05);试验Ⅰ和Ⅱ组奶牛乳脂率分别提高了8.22%(P0.01)和2.97%(P0.05);乳蛋白率分别提高了2.45%(P0.05)和1.05%(P0.05);非脂固形物分别提高了1.29%(P0.05)和0.23%(P0.05),体细胞数分别下降了37.31%和19.34%,但差异均不显著(P0.05);牛奶中乳尿素氮含量分别降低了5.29%(P0.05)和7.58%(P0.01)。结果表明泌乳前期奶牛补饲一定量的植物甾醇能够提高产奶量和改善乳成分。     

Concentrations of buparvaquone in milk and tissue of dairy cows

AIM: To determine the concentration of the anti-theilerial drug buparvaquone in the milk and tissue of dairy cattle following treatment with two different formulations, and to assess the effect of clinical theileriosis on the concentration of buparvaquone in milk.

METHODS: Healthy lactating dairy cows (n=25) were injected once (Day 0) I/M with 2.5?mg/kg of one of two formulations of buparvaquone (Butalex; n=12 or Bupaject; n=13). Milk samples were collected from all cows daily until Day 35. Five cows were slaughtered on each of Days 56, 119, 147, 203 and 328, and samples of liver, muscle and injection site tissue collected. Milk samples were also collected from cows (n=14) clinically affected with theileriosis for up to 21 days after treatment with buparvaquone. Milk and tissue samples were analysed by liquid chromatography-mass spectrometry; limits of detection (LOD) were 0.00018?mg/kg for muscle and 0.00023?mg/L for milk. Concentrations of buparvaquone in milk and tissues were log₁₀-transformed for analysis using multivariate models.

RESULTS: In healthy cows, concentrations of buparvaquone in milk declined with time post-treatment (p<0.001), but were above the LOD in 11 of 25 cows at Day 35. Concentration in milk was higher one day after treatment in cows treated with Butalex than in cows treated with Bupaject, but not different thereafter (p=0.007). Concentrations of buparvaquone in muscle were below the LOD for four of five animals at Day 119 and for all animals by Day 147, but were above the LOD at the injection site of one cow, and in the liver of three cows at Day 328. Tissue concentrations did not differ with formulation nor was there a formulation by time interaction (p>0.3).

Concentrations of buparvaquone in the milk of clinically affected animals were not different from those of healthy animals at 1 and 21 days post-treatment (p=0.72). Between 21 and 25 days post-treatment concentrations were below the LOD in 9/14 milk samples from clinically affected cows.

CONCLUSIONS: Detectable concentrations of buparvaquone were found in the milk of some cows for at least 35 days and in the liver and injection site of some cows until at least 328 days after injection. There were no biologically meaningful differences in milk or tissue concentrations between the formulations, or in the milk concentrations for cows that were clinically affected compared with those that were healthy at the time of treatment.     

过瘤胃赖氨酸对奶牛产乳量及乳成分的影响

试验采用随机分组试验设计,选择健康的中国荷斯坦奶牛48头,按照胎次、产奶量、泌乳日期一致原则,均匀分成4组,试验各组基础日粮相同,就饲粮中添加过瘤胃赖氨酸(Lys)对乳牛产乳量及乳成分的影响进行研究。4个处理组分别为:对照组(0添加组)不添加过瘤胃赖氨酸(RPLys)和试验Ⅰ组添加10 g(/头.d)、试验Ⅱ组添加20 g(/头.d)和试验Ⅲ组添加30 g(/头.d)。试验结果显示:经过饲喂后,试验各组与对照组相比,产奶量显著提高;试验Ⅲ组和试验Ⅱ组都与对照组差异显著(P0.05),其中试验Ⅲ组与对照组差异极显著(P0.01);乳蛋白含量有所提高,其中试验Ⅲ组与对照组有显著差异(P0.05);其他乳成分指标略有提高,但差异不显著(P0.05)。     

低酸度酒精阳性乳患牛乳汁蛋白组分及氨基酸含量变化

采用聚丙烯酰胺凝胶电泳和酸水解法对低酸度酒精阳性乳患牛乳汁中蛋白组分及17种氨基酸含量进行了测定。结果显示,酒精阳性乳患牛乳汁中总蛋白、SA、lgG-H、-αLG、-βLG相对百分含量无显著变化(P0.05),tCN相对百分含量显著降低(P0.05);在酪蛋白中,-αCN相对百分含量无显著变化(P0.05),-βCN相对百分含量上升(P0.05),-κCN相对百分含量极显著下降(P0.01);17种氨基酸中,Cys含量极显著下降(P0.01),而Arg含量极显著上升(P0.01),Leu含量亦呈上升趋势(P0.05)。结果表明,酒精阳性乳患牛乳汁中主要蛋白组分及氨基酸的含量均发生了变化,乳汁中酪蛋白微球的稳定性遭到了严重破坏,乳汁胶体的稳定性降低,导致酒精试验呈阳性反应。     

胡萝卜对奶牛产奶量及乳成分的影响

试验通过在产奶牛日粮中添加胡萝卜,研究胡萝卜不同饲喂量对舍饲奶牛的奶产量和乳成分的影响。试验牛选用中国荷斯坦奶牛,体重500~600 kg,胎次为头胎、泌乳100 d左右的健康荷斯坦奶牛30头,采用完全随机区组设计,分为3个处理组,试验1组为对照组(基础日粮),试验2组(基础日粮+5 kg胡萝卜)、试验3组(基础日粮+7.5 kg胡萝卜)为试验组,基础日粮由全株青贮玉米、羊草和精料组成。研究结果显示,奶牛在添加胡萝卜后能够显著提高产奶量,90 d后试验2组的产奶量比对照组提高了11.94%(P<0.05),试验3组的产奶量比对照组提高了16.17%(P<0.05),牛奶的风味也得到很大的改善。     

奶牛产乳热的发生及阴离子盐的应用

本文就影响产乳热的发生因素、防治措施及阴离子盐在预防奶牛产乳热中的应用作一介绍。     

饲料甜菜对奶牛产奶量的影响

目的：为探索在奶牛日粮中添加饲料甜菜对其泌乳量的影响,提高奶牛养殖的经济效益。方法：2011年9月20日至11月20日,选择健康黑白花奶牛6头,随机分为试验组（饲料甜菜组）和对照组（普通饲料组）,进行饲料甜菜对奶牛产奶量的影响试验。结果：试验组比对照组头均日产奶量增加2 kg,产奶量提高7.9%,差异极显著（P〈0.01）;试验组比对照组粗饲料采食量增加14%,饲料成本增加504元,差异极显著（P〈0.01）;试验组比对照组头日均收入高6.8元,增加纯收入1 124元,经济效益提高13.2%,差异极显著（P〈0.01）。结论：饲料甜菜饲喂奶牛,牛奶产量和质量明显提高,经济效益提高,在实践中应大力推广。     

Effects of increasing days of exposure to prepartum transition diets on milk production and milk composition in dairy cows

Objective To evaluate the effects of length of exposure to prepartum transition diets on milk yield, fat and protein production. Design Prospective cohort study. The number of days that the cows were fed the prepartum transition diets was the exposure of interest. Procedures Holstein and Holstein x Jersey cows (n = 1008) were enrolled. Diets given in the far-off dry period (from end of lactation until approximately 3 weeks before expected parturition) consisted of ad libitum access to perennial ryegrass pastures. Prepartum transition diets included perennial ryegrass pasture, ryegrass silage, cereal hay, grain, grain by-product, protein meals, BioChlor(R), sodium monensin, virginiamycin or tylosin, MgSO(4), trace elements and vitamins. On a dry matter basis, these contained 16.0% crude protein, 4.2% rumen undegradable protein, and 9.9 mJ metabolisable energy/kg. Diets provided an estimated metabolisable protein balance of 286 g/day and dietary cation anion difference of -150 meq/kg dry matter. Statistical models controlled for effects of herd, calving day, breed, age and gestation period. Results Increasing length of exposure to the prepartum transition diets significantly increased the 4.0% fat- and 3.2% protein-corrected milk yield and milk-protein yield as a linear and quadratic effect. The optimal duration of exposure to the prepartum transition diets was 25 days for fat- and protein-corrected milk production and 22 days for milk protein production. Milk-fat percentage decreased significantly and linearly with increasing exposure to the prepartum transition diets; however, milk-fat yield or milk-protein percentage did not vary significantly with duration of exposure to the diets. Conclusions Increasing exposure to prepartum transition diets increased milk and milk-protein yields and decreased the milk fat-percentage, but not the milk-protein percentage or milk-fat yield. Aust Vet J 2008;86:341-351.     

Relationship between fat accumulation in the liver and energy intake, milk fat yield and blood metabolites in dairy cows

In the present study, 42 multiparous Holstein cows were used to investigate the relationship between fat accumulation in the liver and dry matter intake, milk yield and blood metabolites. Based on the percentage of fat in the liver cell at 2 weeks post‐parturition, the cows were classified into three groups. These groups were: (i) less than 10% of fat (normal group, n = 29); (ii) 10–20% of fat (mild group, n = 6); and (iii) more than 20% of fat (moderate group, n = 7). The bodyweight of the moderate group was high (771 kg) before calving. The sufficiency rates of total digestible nutrients (TDN) were remarkably decreased (approximately 65%) in early lactation. The milk fat yield and milk fat composition of the moderate group were higher (P < 0.05) than the other groups at 1 and 2 weeks post‐parturition. It was suggested that non‐esterified fatty acids (NEFA) mobilized from adipose tissues was directly used by the mammary gland for synthesis of milk fat. The percentage of bromsulfalein (BSP) retention of the moderate group was high (21.1%) at 30 min, and it showed that the BSP clearance function was significantly decreased. The concentrations of NEFA, β‐hydroxybutyric acid and glucose were appropriate indicators of energy status; however, aspartate aminotransferase, γ‐glutamyl transpeptidase and total bilirubin were not sensitive indicators of a moderate fatty liver. Thus, high‐yielding cows that calve in an overweight condition are more likely to develop excessive fat accumulation in the liver because of great mobilization from adipose tissues post‐parturition. In cows with a moderately fatty liver, a decrease in TDN sufficiency rates, an increase of milk fat yield and a reduction of liver function were observed in early lactation. The increase of serum NEFA and milk fat composition resulting from mobilization of adipose tissues helped to diagnose moderate fatty liver.     

过瘤胃氨基酸高能复合物对奶牛产奶量及乳成分的影响

为研究不同过瘤胃氨基酸高能复合物对奶牛产奶量及乳成分的影响,试验选择胎次(3～5胎)、产奶量、产犊日期相近,体重(600±20)kg健康荷斯坦泌乳高峰期奶牛24头,随机分为4组,每组6头。1组为对照组,饲喂牛场常规日粮;2、3、4组为试验组,分别在常规日粮基础上添加过瘤胃氨基酸高能复合物Ⅰ、Ⅱ、Ⅲ500 g/(d.头)。正式期60 d。结果表明:奶牛日粮中添加过瘤胃氨基酸高能复合物后,均可明显提高奶牛产奶量、乳脂率、乳蛋白率及乳中总干物质含量。尤其是复合物Ⅲ,添加效果最为理想,平均日产奶量、乳脂率、乳蛋白率及总干物质含量分别比对照组提高21.19%(P<0.05)、21.31%(P<0.05)、9.72%(P<0.05)和10.34%(P<0.05),平均日校正乳产量提高35.70%(P<0.05)。     

饲料中添加烟酸对夏季奶牛产奶性能的影响

试验选取9头泌乳早期处于热应激的荷斯坦牛,采用3×3拉丁方设计,分别饲喂基础日粮(对照组)和在基础日粮中添加5g/d和10g/d烟酸日粮,研究添加烟酸对奶牛生产性能影响。结果表明:添加5g/d和10g/d烟酸可使奶牛产奶量分别提高13.20%和9.39%(P<0.05);而4%标准乳量无显著差异(P>0.05);添加烟酸对乳蛋白和乳脂率无显著影响(P>0.05)。     

Effect of linseed oil supplementation on performance and milk fatty acid composition in dairy cows

Thirty‐six Holstein‐Friesian crossbred lactating dairy cows were used to determine the effects of linseed oil supplementation on performance and milk fatty acid (FA) profile. Three treatments were as follows: basal diet (56:44 Roughage:concentrate [R:C] ratio, dry matter basis) supplemented with 500 g of palm oil as control (PO), 500 g mixture (1:1, w/w) of palm oil and linseed oil (POLSO) and 500 g of linseed oil (LSO). The LSO supplementation had no effects on total dry matter intake (DMI), milk yield and milk composition. Compared to control cows, cows supplemented with LSO increased milk concentrations of cis‐9,trans‐11 conjugated linoleic acid (CLA) and n‐3 FA (P < 0.05), particularly C18:3n‐3, C20:5n‐3 and C22:6n‐3. Feeding LSO reduced concentrations of milk short‐ and medium‐chain saturated fatty acids (P < 0.05) while it increased concentration of milk unsaturated fatty acids (P < 0.05). Milk proportions of n‐3 FA increased, whereas n‐6/n‐3 ratio decreased in the LSO as compared with the control (P < 0.05). In conclusion, supplementing dairy cows' diet based on corn silage with LSO at 500 g/day could improve the nutritional value of milk with potential health‐beneficial FA without detrimental effect on milk composition or cow's performance.     

Effect of the type of silage on milk yield,intake and rumen metabolism of dairy cows grazing swards with low herbage mass

The aim of this study was to evaluate the effect of herbage allowance (HA) and type of silage supplemented (TS) on milk yield, dry matter intake (DMI) and metabolism of dairy cows in early lactation. Thirty‐six Holstein‐Friesian dairy cows were allocated to four treatments derived from an arrangement of two HA (LHA = 17 or HHA = 25 kg of DM/cow/day) and two TS (grass (GS) or maize (MS)). Herbage allowance had no effect on DMI or milk yield. Rumen pH and NH₃‐N concentration were not affected by HA. The efficiency of microbial protein synthesis in the rumen (microbial protein (MP)) was affected by HA with 21.5 and 23.9 g microbial nitrogen per kg ruminal digestible organic matter for LHA and HHA, respectively (P < 0.05). Supplementation with MS showed higher values of milk yield by 2.4 kg/cow/day (P < 0.001), milk protein content by 0.10 % (P < 0.023) and herbage DMI by 2.2 kg/cow/day, and showed lower values for milk urea compared to GS (P < 0.001). The former results suggest that TS had a greater effect on milk yield, total feed intake and energy intake than increase in herbage allowance; however, increase in HA had greater effects on MP than TS.     

全混合日粮对奶牛产乳性能的影响

试验选用了12头奶牛,根据产奶量、泌乳天数和胎次相近的原则分为试验组和对照组,研究全混合日粮对奶牛产乳性能的影响。试验结果表明,试验组4％标准乳产量比对照组提高1 24kg,差异显著(P<0．05),乳脂率及乳脂、乳糖和乳固形物含量也分别比对照组显著提高11．60％、17．50％、13．21％和9．86％(P<0.05)。     

Effect of feeding Bacillus subtilis natto fermentation product on milk production and composition, blood metabolites and rumen fermentation in early lactation dairy cows

This experiment was conducted to determine the effect of Bacillus subtilis natto fermentation product supplementation on blood metabolites, rumen fermentation and milk production and composition in early lactation dairy cows. Thirty-six multiparous Holstein cows (DIM = 29 ± 6 days, parity = 2.8 ± 1.1) were blocked by DIM and parity and then randomly assigned to three treatments (12 per treatment) in a 9-week trial. Cows in control, DFM1 and DFM2 were fed TMR diets supplemented with 0, 6 and 12 g of B. subtilis natto solid-state fermentation product per day per cow respectively. Plasma non-esterified fatty acids were lower (p = 0.03) in DFM1 and DFM2 compared with control cows (633 and 639 vs. 685 μm). Ruminal propionate increased (23.9 vs. 26.3 and 26.9/100 mol, control vs. DFM1 and DFM2 respectively) and acetate decreased (64.2 vs. 62.7 and 62.1/100 mol, control vs. DFM1 and DFM2 respectively) with increasing B. subtilis natto fermentation product supplementation. DMI of the cows in three treatments was not affected by B. subtilis natto fermentation product supplementation, but milk yield was 3.1 and 3.2 kg/day higher for DFM1 and DFM2 than that for control cows on average across the 9-week trial, and significant differences were observed during weeks 5-9 of the trial, which resulted in 9.5% and 11.7% increase in feed efficiency. B. subtilis natto fermentation product supplementation did not affect milk fat percentage and protein yield but increased (p < 0.05) milk fat yield and lactose percentage (p < 0.01) and tended to decrease protein percentage (p = 0.06). The findings show that B. subtilis natto fermentation product was effective in increasing lactation performance of early lactation dairy cows possibly by altering the rumen fermentation pattern without any negative effects on blood metabolites.