高锌对奶牛血清锌和乳锌含量的影响

选择泌乳中后期的中国荷斯坦奶牛24头,分为4组,每组6头,采用单因子试验设计,研究不同锌添加水平对奶牛血清锌和乳锌含量的影响。试验设:对照组(基础日粮),试验Ⅰ组、Ⅱ组、Ⅲ组分别加锌300、500、800mg/kg日粮干物质。结果表明:(1)各高锌组可极显著提高血清锌水平(P<0.01),且各高锌组间差异显著(p<0.05)。(2)高锌日粮可极显著提高乳锌含量(p〈0.01),试验Ⅰ组、Ⅱ组间差异显著(p<0.05),试验Ⅱ组、Ⅲ组间差异不显著(p>0.05)。     

高铜锌日粮对奶牛生产性能的影响

本文选择经产胎次和产奶量相近的健康中国荷斯坦奶牛32头,随机分成4组,每组8头,分别饲喂基础日粮及添加10 mg/kg Cu+40 mg/kgZn、20 mg/kg Cu+80 mg/kg Zn、30 mg/kg Cu+120 mg/kg Zn的日粮.结果表明添加不同水平的铜锌对牛奶中乳脂率和乳糖含量无显著影响(P＞ 0.05),20 mg/kg Cu+80 mg/kg Zn可提高乳蛋白8 4％(P＜0.05);20 mg/kg Cu+80 mg/kg Zn可提高产奶量7 6％(P＜0.05).     

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)。     

高锌对奶牛生产性能和乳锌含量影响的研究

选择泌乳中后期的健康中国荷斯坦奶牛24头，分为4组，每组6头，采用单因子试验设计、分别饲喂4种不同锌水平的日粮，对照组（基础日粮），试验1、2、3组分别加锌300、500、800mg/kg日粮干物质，研究高锌对奶牛生产性能和乳成分的影响。试验结果表明：（1）各高锌组产奶量与对照组差异不显著（P＞0．05）。（2）高锌日粮不影响乳蛋白含量和乳脂率（P＞0．05）。（3）高锌日粮可显著提高乳锌含量（P＜0．01）。试验1、2、3组乳锌含量分别比对照组提高66．91％、104．83％和115．7％。     

高锌对奶牛生产性能和乳锌含量影响的研究

选择泌乳中后期的健康中国荷斯坦奶牛24头,分为4组,每组6头,采用单因子试验设计,分别饲喂4种不同锌水平的日粮,对照组(基础日粮),试验1、2、3组分别加锌300、500、800mg/kg日粮干物质,研究高锌对奶牛生产性能和乳成分的影响,试验结果表明:①各高锌组产奶量与对照组差异不显著(P>0.05)。②高锌日粮不影响乳蛋白含量和乳脂率(P>0.05)。③高锌日粮可极显著提高乳锌含量(P<0.01),试验1、2、3组乳锌含量分别比对照组提高66.91%、104.83%和115.7%。     

日粮对奶牛生产性能及经济效益的影响

60头中国荷斯坦奶牛饲喂4种不同紫花苜蓿干草配比、不同精粗比的日粮,以研究日粮配方对奶牛生产性能、经济收益的影响,确定最佳日粮配方。试验结果说明,大比例紫花苜蓿干草(紫花苜蓿=24%DM)、低精粗比(40:60)日粮极显著提高乳脂率(P<0.01);日粮营养水平提高(P<0.05),产奶量提高(P<0.01);最佳经济效益日粮为含大比例紫花苜蓿、精料比例低、营养水平较低的日粮(P<0.01);在低的精粗比例下,紫花苜蓿干草不是日粮成本的限制因素,而青贮饲料配比为日粮成本的限制因素。合理安排精粗比例,适当使用紫花苜蓿干草,可提高奶牛饲养经济效益。     

日粮对奶牛生产性能及经济效益的影响

60头中国荷斯坦奶牛饲喂4种不同紫花苜蓿干草配比、不同精粗比的日粮,以研究日粮配方对奶牛生产性能、经济收益的影响,确定最佳日粮配方。试验结果说明,大比例紫花苜蓿干草(紫花苜蓿=24%DM)、低精粗比(40:60)日粮极显著提高乳脂率(P<0.01);日粮营养水平提高,产奶量提高(P<0.05;P<0.01);最佳经济效益日粮为含大比例紫花苜蓿、精料比例低、营养水平较低的日粮(P<0.01);在低的精粗比例下,紫花苜蓿干草不是日粮成本的限制因素,而青贮饲料配比为日粮成本的限制因素。合理安排精粗比例,适当使用紫花苜蓿干草,可提高奶牛饲养经济效益。     

日粮对奶牛生产性能及经济效益的影响

60头中国荷斯坦奶牛饲喂4种不同紫花苜蓿干草配比、不同精粗比的日粮,以研究日粮配方对奶牛生产性能、经济收益的影响,确定最佳日粮配方。试验结果说明,大比例紫花苜蓿干草（紫花苜蓿=24％DM）、低精粗比（40：60）日粮极显著提高乳脂率（P〈0．01）;日粮营养水平提高（P〈0．05）,产奶量提高（P〈0．01）;最佳经济效益日粮为含大比例紫花苜蓿、精料比例低、营养水平较低的日粮（P〈0．01）;在低的精粗比例下,紫花苜蓿于草不是日粮成本的限制因素,而青贮饲料配比为日粮成本的限制因素。合理安排精粗比例,适当使用紫花苜蓿干草,可提高奶牛饲养经济效益。     

日粮对奶牛生产性能及经济效益的影响

60头中国荷斯坦奶牛饲喂4种不同紫花苜蓿干草配比、不同精粗比的日粮,以研究日粮配方对奶牛生产性能、经济收益的影响,确定最佳日粮配方。试验结果说明,大比例紫花苜蓿干草（紫花苜蓿=24％DM）、低精粗比（40：60）日粮极显著提高乳脂率（P〈0．01）;日粮营养水平提高,产奶量提高（P〈0．05;P〈0．01）;最佳经济效益日粮为合大比例紫花苜蓿、精料比例低、营养水平较低的日粮（P〈0．01）;在低的精粗比例下,紫花苜蓿干草不是日粮成本的限制因素,而青贮饲料配比为日粮成本的限制因素。合理安排精粗比例,适当使用紫花苜蓿干草,可提高奶牛饲养经济效益。     

不同蛋白质水平日粮对奶牛生产性能的影响

为了研究不同蛋白质水平日粮对奶牛生产性能的影响,试验将30头体况、年龄、胎次相近的健康荷斯坦奶牛随机分为1,2,3组,分别饲喂蛋白质水平为16.70%、18.60%、20.60%的日粮,测定生产性能指标和乳品质指标。结果表明:随着日粮蛋白质水平的提高,奶牛干物质采食量和产奶量显著增加(P<0.05);乳脂率和乳蛋白率显著降低(P<0.05),乳糖显著高于1,2组(P<0.05),乳中尿素氮3组间差异不显著(P>0.05)。说明日粮中过高的蛋白质水平可以增加奶牛产奶量,但对乳成分并没有改善作用。     

Effects of white,yellow, and blue colored LEDs on milk production,milk composition,and physiological responses in dairy cattle

Light emitting diode (LED) is more energy efficient than incandescent or fluorescent light. This study was to evaluate effects of different colored LEDs on milk production, milk composition, and physiology of Holstein cow. According to milk production and parity, cows (n = 186) were allotted to four treatments: control (natural daylight), white, yellow, and blue LED groups. Of these, 40 cows that had passed 57 day‐in‐milk were used. Yellow and blue LED groups demonstrated greater rates of decline in milk production than control and white LED groups. At the finish point, milk fat, protein, and lactose contents were the lowest in the blue LED group, whereas milk–urea–nitrogen levels were the highest in the yellow and blue LED groups. Extended exposure to blue LED light lowered antioxidant enzyme activity and insulin‐like growth factor‐1 levels. Prolactin concentrations were higher in the white and blue LED groups than in the control. Cortisol level was the highest in the blue LED group among the groups. Nonesterified fatty acid levels in the yellow and blue LED groups decreased to the greatest extent compared to the start point. These results suggest that blue LED light can decrease milk production and generate more stress than white and yellow LED lights.     

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。     

日粮中添加菌糠对奶牛产奶量、乳品质、血液生化指标及抗氧化功能的影响

试验为研究日粮中添加菌糠对荷斯坦奶牛产奶量、乳品质、血液生化指标及抗氧化功能的影响,根据单因素随机设计,将健康、体重接近的90头荷斯坦奶牛随机分为3个处理组,每组30头.对照组奶牛饲喂基础日粮;试验1组饲喂5％的菌糠;试验2组饲喂10％的菌糠.预试期7d,正式试验期30 d.结果 表明:与对照组相比,菌糠组的乳品质指标...     

影响江苏某牛场荷斯坦牛日产奶量和乳成分因素分析

[目的]探究江苏某牛场荷斯坦牛日产奶量和乳成分的影响因素。[方法]试验采集了该规模化牛场2018—2020年139 703条测定数据,并利用多因素方差模型对其进行系统的分析。[结果]不同胎次、测定季节、产犊季节、泌乳月对荷斯坦牛日产奶量、乳脂率、乳蛋白率、体细胞评分、乳尿素氮均有极显著影响(P<0.01)。产奶量与乳脂率、乳蛋白率、体细胞评分均存在极显著负相关。[结论]综上结果,在生产中,应结合胎次、季节、产犊时间、泌乳等多种因素,灵活调整牛群结构、生产规划和饲养管理,以实现提高产奶量和乳品质的目的。     

挤奶频率对奶牛生产性能的影响

文章介绍了挤奶频率对奶牛泌乳性能、繁殖性能、健康与福利等方面的影响。     

The effect of beta and kappa casein genes on milk yield and milk composition in different percentages of Holstein in crossbred dairy cattle

The objective of this study was to compare the genotype, and composite genotype frequency, and the association between beta and kappa casein genes and milk yield (MY), percentage of fat (%Fat), protein (%Prot), and solids non‐fat (%SNF) between two groups of crossbred Holstein: G1 ≤ 87.5% Holstein = 89 cows and G2 > 87.5% Holstein = 142 cows. Five genotypes of beta casein gene were observed. A1A2 and A1B were the most and rarest frequency, respectively, in both groups. Five genotypes of kappa casein gene were found. The highest and the lowest frequency were AA, and BB and BE, respectively, in both groups. Composite genotype A1A2AA was the most frequent in both groups. Linkage disequilibrium (LD) between two genes was detected. Significant differences of frequencies between both groups of both genes were not found. The association of the genes and the traits was different between G1 and G2. Negative effects on the traits were found in both groups. In addition, the stronger effect of the beta casein gene was observed in most of the traits. The conclusions were that different %Holstein caused different significant effects of these genes. A study of the association of these genes within each percentage of Holstein is strongly recommended.     

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.     

An investigation into reduced milk production following dietary alteration on an Irish dairy farm

A nutritional evaluation of an Irish dairy herd indicated gross overfeeding of late lactation cows, over-conditioning of cows at parturition and a high rate of body condition loss in early lactation. Metabolisable-energy based nutritional modelling software was used to guide recommended dietary changes to prevent excessive condition gain in late lactation. Immediately following the implementation of the changes there was an unexpected reduction in performance affecting both milk yield and protein concentration. An investigation into the poor performance revealed underestimation of peak milk yield; over-estimation of maize silage quality; a large difference in the concentrate being fed compared to the concentrate recommended, and failure of the blend of concentrate ingredients to maintain the intended proportions in the in-parlour feeding system. The estimated maximum cumulative effect of these errors was to cause undersupply of energy and protein in the recommended diet of 16% and 3% respectively to cows in early lactation. Use of a net-energy nutritional model would have indicated a requirement for a higher energy supply in this case. This report highlights the challenges in obtaining accurate on-farm data for use in dairy cow nutritional models.     

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)。     

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。