牛至油和过瘤胃蛋氨酸不同组合对奶牛产奶性能和氮排泄的影响

本试验旨在研究牛至油(Oo)和过瘤胃蛋氨酸(RPMet)的不同添加量组合对奶牛产奶性能与氮排泄的影响。选取年龄、体重、胎次、产奶量、乳成分及泌乳期(90±15) d相近的荷斯坦奶牛40头随机分为10个组,每组4头。对照(C)组饲喂基础日粮,试验组饲喂不同添加水平的Oo和RPMet,Oo添加水平分别为11.5(L)、13.0(M)、14.5(H) g·(d·头)^-1;RPMet添加水平分别为22.5(L)、25.0(M)、27.5(H) g·(d·头)^-1,共组成9个不同的添加量组合,分别为LL、ML、HL、LM、MM、HM、LH、MH、HH(第1个字母为Oo添加水平,第2个字母为RPMet添加水平)。预试期15 d,正试期60 d。结果表明:产奶量方面,LL、HL、HM、MH、HH组产奶量极显著高于对照组(P<0.01),以MH组最高。乳成分方面,MH、HM组乳脂率极显著提高(P<0.01);HM、HH组乳蛋白率极显著提高(P<0.01),各试验组在乳体细胞数均极显著低于对照组(P<0.01)。在氮排泄方面,LL、ML、LM、MM、HM、LH、MH、HH组氮排泄极显著低于对照组(P<0.01),以MH组最低。综合考虑上述指标,在本试验条件下,以MH组[Oo 13.0 g·(d·头)^-1、RPMet 27.5 g·(d·头)^-1]组合效果最好。     

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...     

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)。     

日粮添加过瘤胃保护胆碱对喀斯特山区奶牛泌乳性能的影响及其延续效应研究

研究日粮添加过瘤胃胆碱(RPC)对喀斯特山区奶牛泌乳性能及其延续效应的影响。以10头喀斯特山区泌乳盛期奶牛为试验动物,进行自身对照试验设计。试验按照对照期、正试期(试验Ⅰ期、试验Ⅱ期)、延续效应期(试验Ⅲ期)连续进行,每期12 d。其中,正试期RPC每头奶牛的添加水平为40 g/d;试验Ⅲ期停喂RPC以观察其是否可对奶产量产生延续效应。结果表明,对照期、试验Ⅰ期、试验Ⅱ期、试验Ⅲ期奶牛干物质采食量差异不显著(P>0.05)。试验Ⅰ期奶产量显著高于其他3期(25.5∶27.7∶26.5∶24.8 kg/d,P<0.05);正试期(试验Ⅰ期、试验Ⅱ期)奶产量显著高于对照期、延续效应期(25.5∶27.2∶24.8 kg/d,P<0.05);当停喂RPC后,延续效应期奶产量即下降至对照期水平(25.5∶24.8 kg/d,P>0.05)。奶成分不受日粮添加RPC的影响(P>0.05),乳脂、乳固型物含量数值上较对照期有所增加。由此可见,日粮添加RPC有利于提高喀斯特山区奶牛泌乳性能,但未对奶产量表现出延续效应,生产实践中需持续添加。     

日粮添加过瘤胃氨基酸对高产奶牛生产性能、乳成分和经济效益的影响

试验旨在研究日粮添加过瘤胃蛋氨酸和过瘤胃赖氨酸对高产奶牛生产性能、乳成分及经济效益的影响。按照胎次、产奶日期、日产奶量一致的原则,选择处于泌乳高峰期的健康中国荷斯坦奶牛96头,随机分为对照组和试验组,每组48头牛,每头牛1个重复。对照组饲喂基础日粮,试验组饲喂基础日粮+过瘤胃氨基酸[过瘤胃蛋氨酸添加量20 g/(头·d);过瘤胃赖氨酸添加量27 g/(头·d)]。预试期7 d,正试期30 d。结果表明:①日粮添加过瘤胃蛋氨酸和过瘤胃赖氨酸极显著提高奶牛日产奶量3.63%(P0.01),极显著提高饲料转化率4.49%(P0.01)。②日粮添加过瘤胃蛋氨酸和过瘤胃赖氨酸极显著降低尿素氮含量26.92%(P0.01),对乳脂率、乳蛋白率、体细胞数无显著影响(P0.05)。③与对照组相比,试验组奶牛经济效益增加2.30元/(头·d)。在本试验条件下,日粮添加过瘤胃蛋氨酸和过瘤胃赖氨酸能够提高高产奶牛产奶量,提高饲料转化率,提高经济效益。     

日粮甜菜碱和过瘤胃脂肪对育肥湖羊生长性能和消化参数的影响

选取48只3月龄湖羊公羔,随机分为6个处理组、每个处理组8个重复,每个重复1只羊,试验过渡期10d、预试期7d、试验期50d。采用2×3双因素试验,即两个RPF添加浓度(0和2.4%),3个Bet水平(0、4和8g·d-1)。旨在研究添加甜菜碱(betaine,Bet)和过瘤胃脂肪(rumen protected fat,RPF)对育肥湖羊生长性能、血液参数和瘤胃发酵参数的影响。结果表明,1)添加2.4%的RPF能显著降低湖羊日增重、采食量和末体重(P0.05),显著提高血浆中胆固醇(TCH)和甘油三酯(TG)含量(P0.05),对血浆中的葡萄糖(Glu)含量无显著影响(P0.05);日粮添加Bet对育肥湖羊生长性能和血液指标无显著影响(P0.05)。二者交互对育肥湖羊生长性能和血液指标无显著作用(P0.05)。2)添加2.4%的RPF能显著降低饲料中中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)消化率(P0.05),对干物质(DM)、有机物(OM)和粗蛋白(CP)消化率无显著影响(P0.05),对瘤胃挥发性脂肪酸浓度及比例无显著影响(P0.05);日粮添加Bet对养分消化率和瘤胃挥发性脂肪酸浓度及比例无显著影响(P0.05)。二者互作对瘤胃发酵和养分消化率无显著影响(P0.05)。综上可知,在本研究条件下,甜菜碱对湖羊无调控作用,RPF主要通过降低湖羊采食量及纤维消化率影响生产性能。实际生产中,若以羊肉产量为目标不宜添加2.4%RPF。     

Effect of raw soya bean particle size on productive performance and digestion of dairy cows

Differing soya bean particle sizes may affect productive performance and ruminal fermentation due to the level of fatty acid (FA) exposure of the cotyledon in soya bean grain and because the protein in small particles is more rapidly degraded than the protein in large particles, which influence ruminal fibre digestion and the amounts of ruminally undegradable nutrients. The objective of this experiment was to investigate the effects of raw soya bean particle size on productive performance, digestion and milk FA profile of dairy cows. Twelve Holstein cows were assigned to three 4 × 4 Latin squares with 21‐day periods. At the start of the experiment, cows were 121 days in milk (DIM) and yielded 30.2 kg/day of milk. Cows were fed 4 diets: (i) control diet (CO), without raw soya bean; (ii) whole raw soya bean (WRS); (iii) cracked raw soya bean in Wiley mill 4‐mm screen (CS4); and (iv) cracked raw soya bean in Wiley mill 2‐mm screen (CS2). The inclusion of soya beans (whole or cracked) was 200 g/kg on dry matter (DM) basis and partially replaced ground corn and soya bean meal. Uncorrected milk yield and composition were not influenced by experimental diets; however, fat‐corrected milk (FCM) decreased when cows were fed soya bean treatments. Soya bean diets increased the intake of ether extract (EE) and net energy of lactation (NE_L), and decreased the intake of DM and non‐fibre carbohydrate (NFC). Ruminal propionate concentration was lower in cows fed WRS than cows fed CS2 or CS4. Cows fed cracked raw soya bean presented lower nitrogen in faeces than cows fed WRS. The milk of cows fed WRS, CS2 and CS4 presented higher unsaturated FA than cows fed CO. The addition of raw soya bean in cow diets, regardless of the particle size, did not impair uncorrected milk yield and nutrient digestion, and increased the concentration of unsaturated FA in milk. Cows fed cracked raw soya bean presented similar productive performance to cows fed whole raw soya bean.     

Effects of feeding rumen-protected choline on incidence of diseases and reproduction of dairy cows

The objectives of this study were to determine the effects of feeding rumen-protected choline (RPC) to dairy cows on the incidence of disease in early lactation, and on their fertility as measured by return to ovarian cyclicity and pregnancies per insemination (P/AI). In the first experiment, 369 cows were fed 15 g/day of RPC between 25 days pre-calving and 80 days post calving. In the second experiment, 578 primigravid cows were fed 15 g/day of RPC for the last 21 days of gestation only. In both experiments, P/AI were evaluated for the first and second inseminations, and health disorders were monitored daily until 90 days after calving. Return to cyclicity was evaluated in experiment 1 only, on days 51 and 61 post calving. In the first experiment, feeding RPC reduced the incidence of clinical ketosis, mastitis, and morbidity, and the number of cases of mastitis per cow. Feeding RPC did not influence cyclicity and P/AI. In the second experiment, cows fed RPC tended to have greater morbidity than controls because of an increased incidence of metritis and fever, although the incidence of retained fetal membranes was lower. The P/AI for first and second inseminations were similar between treatments. Supplementing the diets of dairy cattle with RPC from before until after calving improved the health of early lactation cows. However, in primigravid cows feeding RPC before calving only had mixed effects on health. Feeding RPC had no beneficial effects on reproduction in either experiment.     

氨基酸过瘤胃保护方法及其在奶牛营养中的应用

保护性氨基酸是调控奶牛小肠氨基酸平衡最直接有效的方法。作者主要就氨基酸的保护方法、保护性氨基酸的应用效果及保护性氨基酸效果的检测方法进行了综述。     

苜蓿青贮料替代苜蓿青干草对奶牛生产性能及乳品质的影响

试验旨在探讨苜蓿青贮料替代不同比例苜蓿青干草对奶牛生产性能、乳品质、营养物质表观消化率、血液生化指标及经济效益的影响。选取体重、产奶量、胎次相近的健康泌乳中期中高产中国荷斯坦奶牛15头,随机分为3组,每组5个重复,每个重复1头牛。对照组饲喂4.0 kg苜蓿青干草,试验A、B组分别用4.4,8.8 kg苜蓿青贮料代替2.0和4.0 kg等干物质的苜蓿青干草,正试期64 d。结果表明,1)各组间干物质采食量差异不显著(P>0.05),B组产奶量显著低于对照组(P<0.05),A组与对照组、B组间差异不显著(P>0.05); 2)用50%,100%的苜蓿青贮料替代等干物质的苜蓿青干草,其乳蛋白、乳脂率、乳糖均有所改善,但只有B组的乳脂率显著高于对照组(P<0.05),其余指标各组间差异均不显著(P>0.05);3)A、B组与对照组的中性洗涤纤维表观消化率、钙表观消化率无显著性差异(P>0.05),A、B组间粗蛋白和磷表观消化率差异不显著(P>0.05),但是粗蛋白表观消化率均显著低于对照组、磷表观消化率均显著高于对照组(P<0.05);4)苜蓿青贮料替代苜蓿青干草其血清总蛋白、白蛋白、血尿素氮、血糖、二氧化碳结合力等指标没有显著性改变(P>0.05);5)试验A、B组经济效益均有所增加,其中A组的净增收益最高,为0.61元/(头·d)。综上,用4.4 kg苜蓿青贮料代替2.0 kg苜蓿青干草对中高产奶牛是适宜的,能提高其生产性能,改善乳品质,增加收益。     

过瘤胃蛋氨酸和肉桂醛对奶牛血液生化指标的影响

试验旨在研究过瘤胃蛋氨酸(rumen-protected methionine,RPMet)和肉桂醛(cinnamic al-dehyde,CA)不同添加组合对奶牛血液生化指标的影响。选取年龄、体重、胎次、产奶量、乳成分及泌乳期[(90±15)d]相近的荷斯坦奶牛40头,随机分为10组,每组4头。对照组(C)饲喂基础日粮,试验组补饲不同水平组合的RPMet和CA,其中RPMet设3个水平,添加量分别为20(L)、25(M)、30(H)g/(d·头);CA设3个水平,添加量分别为15(L)、18(M)、21(H)g/(d·头),共9个不同水平组合,分别为LL、ML、HL、LM、MM、HM、LH、MH、HH。预试期15 d,正试期60 d。结果表明:饲粮中补饲RPMet和CA可以提高血清中总蛋白、白蛋白和生长激素的含量,降低血清中血糖、尿素氮和胰岛素的含量。在本试验条件下,综合考虑血液生化指标,最佳添加量组合为过瘤胃蛋氨酸30 g/(d·头),肉桂醛15 g/(d·头)。     

Effects of rumen-protected methionine in a low protein ration on metabolic traits and performance of early lactating cows as opposed to rations with elevated crude protein content

A 5‐week experiment with 24 multiparous early lactating Brown Swiss cows was conducted to investigate the effects of supplementary rumen‐protected methionine in conjunction with dietary protein reduction on metabolism and performance after 1 week of control measurement. Three rations containing 175, 150 and 125 g of crude protein/kg feed dry matter were supplemented with methionine. The fourth ration, also only containing 125 g of crude protein/kg dry matter, remained unsupplemented. The four treatment groups had a similar metabolic supply of other essential amino acids, protein and energy, as calculated by various approaches. The two low protein rations were, however, slightly deficient in ruminally degraded protein. Treatment effects remained low on feed intake, forage meal pattern, milk yield and fat as well as lactose content. In contrast, the content and yield of milk protein significantly declined only in the unsupplemented low protein ration relative to the initial value. Compared with this ration, the decline in milk protein yield was clearly delayed in the supplemented low protein ration. Blood plasma methionine tended to be reduced without supplementation and to be increased with additional methionine. Supplementation of methionine reduced other plasma amino acids. Plasma insulin, glucose, lactate, ketone bodies and aspartate amino transferase activity indicated a certain liver stress and a somewhat elevated energy requirement with high and particularly with low protein content (when unsupplemented). Methionine improved metabolic protein utilization, followed by the lowest plasma, urine and milk urea levels in the supplemented low protein diet. In conclusion, no major adverse effects were assessed under the conditions tested. Supplementation of methionine may nevertheless be useful in rations with particularly low protein content fed to early lactating cows in order to prevent negative long‐term effects which were only visible here as trends.     

影响奶牛生产性能及经济效益的因素

在规模化牛场的生产过程中,品种、营养、牛群结构、饲养管理、疾病防治等因素对奶牛生产及经济效益有很大影响.而选择高产品种、调整营养水平、建立合理的牛群结构、采取适宜的饲养管理和疾病防治措施,不仅能够提高奶牛的生产性能、繁殖性能,还能降低饲养成本、提高经济效益.文章对影响奶牛生产性能及经济效益的因素进行论述,为促进我国规模...     

肝脏、乳腺和体脂活体采样对奶牛生产性能影响研究

为了探讨肝脏、乳腺和体脂活体采样对奶牛生产性能的影响,本研究对8头荷斯坦泌乳牛进行了活体采样手术,记录采样操作和术后护理过程,同时测定体温、采食和产奶量的变化状况。结果表明,规范的活体采样手术操作和良好的术后护理对奶牛体温和干物质采食量影响较小,产奶量可在术后第3天恢复正常。     

日粮添加共轭亚油酸钙盐和葵花油对奶牛产奶性能及饲料消化率的影响

试验研究了奶牛日粮中添加过瘤胃共轭亚油酸(Ca-CLA),同时添加葵花油对奶牛生产性能和饲料利用率的影响。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。对照组(A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每天每头牛分别添加Ca-CLA100g(B组)、葵花油350g(C组)、Ca-CLA100g+葵花油350g(D组)、Ca-CLA50g+葵花油175g(E组)。试验共进行52d。结果表明:C组产奶量较对照组差异不显著(P>0.05),B、D、E组产奶量较对照组都分别显著提高2.20%、9.95%、11.16%(P<0.05);B、C、D、E组牛奶的乳脂率较对照组都分别显著降低15.00%、6.74%、21.74%、14.35%(P<0.05)。与对照组相比,B组显著提高饲料中EE、CP、NDF、ADF消化率;C组除脂肪外其它营养成分消化率有降低的趋势但差异不显著;D、E组除脂肪消化率显著提高外,其它营养成分消化率差异不显著。     

Immune response and milk production of dairy cows fed graded levels of rumen-protected glutamine

The objective of the study was to determine the effects of dietary supplementation with glutamine on the immune function and milk production of dairy cows. The experiment involved 24 Friesian cows, divided into three groups of eight each, according to the level of rumen-protected glutamine supplementation: a diet with no supplementation (Control), a diet supplemented with 160 g/day/cow (G160) and a diet supplemented with 320 g/day/cow (G320). At 0, 30, and 60 days of the experiment, lymphocyte response to phytohemoagglutinin (PHA) was determined in vivo for each animal. Humoral response to chicken egg albumin (OVA) and interleukin - (IL)-1β, IL-6 and IL-10 plasma levels were measured at 0, 15, 30, 45, and 60 days. Results demonstrate that supplementing 160 g/day/cow of glutamine can modulate immune responses of dairy cows and enhance the amino acid profile of cow milk.     

Effect of yeast culture on milk production and metabolic and reproductive performance of early lactation dairy cows

Background

The main objective of this study was to estimate the effect of supplementation with Saccaromyces cerevisiae (SC) (Yea-Sacc^® 1026) on milk production, metabolic parameters and the resumption of ovarian activity in early lactation dairy cows.

Methods

The experiment was conducted during 2005/2006 in a commercial tied-house farm with an average of 200 milking Estonian Holstein Friesian cows. The late pregnant multiparous cows (n = 46) were randomly divided into two groups; one group received 10 g yeast culture from two weeks before to 14 weeks after calving. The groups were fed a total mixed ration with silages and concentrates. Milk recording data and blood samples for plasma metabolites were taken. Resumption of luteal activity was determined using milk progesterone (P₄) measurements. Uterine bacteriology and ovarian ultrasonography (US) were performed and body condition scores (BCS) and clinical disease occurrences were recorded. For analysis, the statistical software Stata 9.2 and R were used to compute Cox proportional hazard and linear mixed models.

Results

The average milk production per cow did not differ between the groups (32.7 ± 6.4 vs 30.7 ± 5.3 kg/day in the SC and control groups respectively), but the production of milk fat (P < 0.001) and milk protein (P < 0.001) were higher in the SC group. There was no effect of treatment on BCS. The analysis of energy-related metabolites in early lactation showed no significant differences between the groups. In both groups higher levels of β-hydroxybutyrate (BHB) appeared from days 14 to 28 after parturition and the concentration of non-esterfied fatty acid (NEFA) was higher from days 1–7 post partum (PP). According to US and P₄ results, all cows in both groups ovulated during the experimental period. The resumption of ovarian activity (first ovulations) and time required for elimination of bacteria from the uterus did not differ between the groups.

Conclusion

Supplementation with SC had an effect on milk protein and fat production, but did not influence the milk yield. No effects on PP metabolic status, bacterial elimination from the uterus nor the resumption of ovarian activity were found.