Microbial signature inferred from genomic breeding selection on milk urea concentration and its relation to proxies of nitrogen-utilization efficiency in Holsteins

Increasing the nitrogen-utilization efficiency (NUE) of dairy cows by breeding selection would offer advantages from nutritional, environmental, and economic perspectives. Because data collection of NUE phenotypes is not feasible in large cow cohorts, the cow individual milk urea concentration (MU) has been suggested as an indicator trait. Considering the symbiotic interplay between dairy cows and their rumen microbiome, individual MU was thought to be influenced by host genetics and by the rumen microbiome, the latter in turn being partly attributed to host genetics. To enhance our knowledge of MU as an indicator trait for NUE, we aimed to identify differential abundant rumen microbial genera between Holstein cows with divergent genomic breeding values for MU (GBVMU; GBV_HMU vs. GBV_LMU, where H and L indicate high and low MU phenotypes, respectively). The microbial genera identified were further investigated for their correlations with MU and 7 additional NUE-associated traits in urine, milk, and feces in 358 lactating Holsteins. Statistical analysis of microbial 16S rRNA amplicon sequencing data revealed significantly higher abundances of the ureolytic genus Succinivibrionaceae UCG-002 in GBV_LMU cows, whereas GBV_HMU animals hosted higher abundances of Clostridia unclassified and Desulfovibrio. The entire discriminating ruminal signature of 24 microbial taxa included a further 3 genera of the Lachnospiraceae family that revealed significant correlations to MU values and were therefore proposed as considerable players in the GBVMU–microbiome–MU axis. The significant correlations of Prevotellaceae UCG-003, Anaerovibrio, Blautia, and Butyrivibrio abundances with MU measurements, milk nitrogen, and N content in feces suggested their contribution to genetically determined N-utilization in Holstein cows. The microbial genera identified might be considered for future breeding programs to enhance NUE in dairy herds.     

Factors affecting energy and nitrogen efficiency of dairy cows: A meta-analysis

A meta-analysis was performed to explore the correlation between energy and nitrogen efficiency of dairy cows, and to study nutritional and animal factors that influence these efficiencies, as well as their relationship. Treatment mean values were extracted from 68 peer-reviewed studies, including 306 feeding trials. The main criterion for inclusion of a study in the meta-analysis was that it reported, or permitted calculation of, energy efficiency (Eeff; energy in milk/digestible energy intake) and nitrogen efficiency (Neff; nitrogen in milk/digestible nitrogen intake) at the digestible level (digestible energy or digestible protein). The effect of nutritional and animal variables, including neutral detergent fiber, acid detergent fiber (ADF), digestible energy, digestible protein, proportion of concentrate (PCO), dry matter intake, milk yield, days in milk, and body weight, on Eeff, Neff, and the Neff:Eeff ratio was analyzed using mixed models. The interstudy correlation between Eeff and Neff was 0.62, whereas the intrastudy correlation was 0.30. The higher interstudy correlation was partly due to milk yield and dry matter intake being present in both Eeff and Neff. We, therefore, also explored the Neff:Eeff ratio. Energy efficiency was negatively associated with ADF and PCO, whereas Neff was negatively associated with ADF and digestible energy. The Neff:Eeff ratio was affected by ADF and PCO only. In conclusion, the results indicate a possibility to maximize feed efficiency in terms of both energy and nitrogen at the same time. In other words, an improvement in Eeff would also mean an improvement in Neff. The current study also shows that these types of transverse data are not sufficient to study the effect of animal factors, such as days in milk, on feed efficiency. Longitudinal measurements per animal would probably be more appropriate.     

Starch–protein interaction in the rumen of weaned dairy calves

The objectives of this study were to investigate the effect of starch and protein interaction on rumen environment, in situ digestion, and total-tract digestibility of nutrients in weaned dairy calves between 8 and 16 wk of age. Sixteen rumen-cannulated calves were randomly divided into 4 dietary treatment groups with 4 calves fed in each treatment. The treatment diets had 2 levels of starch [18%, low starch (LS), or 38%, high starch (HS)] and 2 levels of protein [16%, low protein (LP), or 22%, high protein (HP)] on a dry matter (DM) basis in calf grower: (1) LPLS, (2) LPHS, (3) HPLS, and (4) HPHS. Calves were fed for ad libitum intake (95% assigned grower and 5% grass hay), and refusals were collected weekly. Total-tract digestibility collection and in situ digestibility procedures were performed for each calf at 11 and 15 wk. Samples for in situ digestibility, grass hay (GH), soybean hulls (SBH), wheat middlings (WM), ground corn (GrC), and soybean meal (SBM) were incubated for 9 and 24 h. There was no starch and protein interaction on total-tract digestibility of calves. Total-tract DM, neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibility, and feed efficiency were affected by both protein and starch inclusion level in calf diet. Total-tract starch digestibility was lower for LS diets. Dry matter digestibility and feed efficiency were greater in calves fed HP and HS diets compared with calves fed LP and LS diets, respectively. Fiber digestibility (NDF and ADF) was less in calves fed HS diets compared with calves fed LS diets but was greater in calves fed HP diets compared with calves fed LP diets. Level of protein did not affect in situ DM and NDF disappearance of GH, but HP increased in situ DM and NDF disappearance of SBH. High-starch diets decreased DM and NDF disappearance of both GH and SBH. At 20 h after feeding, ruminal pH was 0.51 unit higher in calves fed HPHS compared with calves fed LPHS. Total ruminal VFA and proportion of propionate was greater with HS versus LS, whereas proportion of acetate was greater with LS versus HS. The DM disappearance of SBM and WM and NDF disappearance of WM was greater for calves fed HPHS compared with calves fed LPHS at 11 wk of age. In our study, when HP was fed with HS, rumen pH, in situ digestion of WM and SBM, and total-tract digestion of DM, NDF, and ADF increased. This provides evidence for starch–protein interaction in the rumen of recently weaned dairy calves. Improvements in total-tract and in situ digestibility suggest that both protein and starch levels are important for 8- to 16-wk-old calves.     

造纸过程节能潜力分析与节能技术应用

介绍了造纸脱水过程的特点,对比分析了国内外造纸过程的能耗状况,阐述了造纸过程各工段的用能状况及节能潜力.结合生产实际探讨了造纸过程的节能技术,重点介绍了干燥部相关的节能技术,并对其应用做了综述.     

基于DEA交叉效率模型的浙江省纺织产业绿色转型效率评价

从绿色经济效益、绿色生产制造、绿色生态保护、绿色社会支持4个方面构建了纺织产业绿色转型效率评价指标体系,并结合DEA交叉效率模型,根据浙江省及其11个地级市2014—2018年的数据,分析了浙江省纺织产业绿色转型的效率水平及地区差异。结果表明:2014年以来,浙江省纺织产业绿色转型效率不断上升,但整体处于较低水平。经过投影分析证明,浙江省纺织产业的生产要素投入尚未达到最优配置,绿色产出不足;浙江省11个地级市纺织产业绿色转型发展水平不均衡,存在明显的市际差异。最后提出提升浙江省纺织产业绿色转型效率的政策建议。     

纸机干燥部能源效率在线监测与评价方法研究

通过分析纸机干燥部的能耗,初步探索了干燥部能源效率在线监测与评价方法,提出了干燥部能源效率在线监测的4类指标,即干燥部蒸汽单耗、干燥部热效率、通风与余热回收子系统电单耗、通风与余热回收子系统热回收效率,并建立了各个指标的计算模型;基于提出的指标对干燥部能源效率的评价方法进行了进一步拓展研究,提出的干燥部能源效率在线评价方法可从能效对标和能效等级2个维度实时评价干燥部能效水平。     

Three-breed rotational crossbreds of Montbéliarde,Viking Red,and Holstein compared with Holstein cows for feed efficiency,income over feed cost,and residual feed intake

Rotational 3-breed crossbred cows of Montbéliarde, Viking Red, and Holstein (CB) were compared with Holstein (HO) cows for alternative measures of feed efficiency as well as income over feed cost (IOFC) and residual feed intake (RFI) during the first 150 d of first, second, and third lactations. Primiparous and multiparous CB (n = 63 and n = 43, respectively) and HO (n = 60 and n = 37, respectively) cows were fed the same total mixed ration twice daily with refusals weighed once daily. Feed was analyzed for dry matter content, net energy for lactation, and crude protein content. Body weight (BW) was recorded twice weekly. Daily production of milk, fat, and protein were estimated from monthly test days with best prediction. Measures of efficiency from 4 to 150 d in milk (DIM) were feed conversion efficiency (FCE), defined as fat plus protein production (kg) per kilogram of dry matter intake (DMI); ECM/DMI, defined as kilograms of energy-corrected milk (ECM) per kilogram of DMI; net energy for lactation efficiency (NE_LE), defined as ECM (kg) per megacalorie of net energy for lactation intake; crude protein efficiency (CPE), defined as true protein production (kg) per kilogram of crude protein intake; and DMI/BW, defined as DMI (kg) per kilogram of BW. The IOFC was defined as revenue from fat plus protein production minus feed cost. The RFI from 4 to 150 DIM for each lactation was the residual error remaining from regression of DMI on milk energy output (Mcal), metabolic BW, and energy required for change in BW (Mcal). Statistical analysis of measures of feed efficiency and RFI for primiparous cows included the fixed effects of year of calving and breed group. For multiparous cows, statistical analysis included breed as a fixed effect and cow as a repeated effect nested within breed group. Primiparous CB cows had higher means for FCE (+5.5%), ECM/DMI (+4.0%), NE_LE (+4.0%), and CPE (+5.2%) and a lower mean DMI/BW (–5.3%) than primiparous HO cows. Primiparous CB cows ($875) also had higher mean IOFC than primiparous HO cows ($825). In addition, mean RFI from 4 to 150 DIM was significantly lower (more desirable) for primiparous CB cows than HO cows. Likewise, multiparous CB cows had higher means for FCE (+8.2%), ECM/DMI (+5.9%), NE_LE (+5.8%), and CPE (+8.1%) and a lower mean for DMI/BW (–4.8%) than multiparous HO cows. Multiparous CB cows ($1,296) also had a higher mean for IOFC than multiparous HO cows ($1,208) and a lower mean for RFI from 4 to 150 DIM than HO cows.     

不同蒸煮设备的能耗分析

介绍了化学法蒸煮木浆的卡米尔连蒸、碱法立锅、酸法立锅的热效率和能量效率及化学法蒸煮草浆的横管连蒸、蒸球的热效率和能量效率。     

测定卷发剂卷发效果的一种方法

本文介绍一种采用模拟卷发过程,以测定头发的卷曲半径及卷曲保留率的方法,定量地衡量卷发剂的卷曲效果。     

纺织行业节能减排技术应用

高能耗、高水耗和高排放是纺织生产急需解决的问题,简述了革新染整工艺技术,增加高效、连续、短流程的节能减排染整设备,提高能源效率和资源利用率,研发新型多功能衬衣等几方面的改革、调整措施。实践证明这一系列措施在提高产品质量、降低成本、节能减排方面有显著的成效,实现了清洁、绿色生产。     

1.4m紧凑型加热器可取代高温短程加热器用于变形整理PA,PET和PP

利用这种新型加热器可节约能源高达 70 % ;高温技术适用于大批量生产 ,而不适用于灵活生产 ;简洁的流程使生产设备维修容易。     

糖厂蒸发站热力效能的评价方法

本文根据有效能分析的方法，提出了蒸发站热力效能的评价方法，这个方法对蒸发站耗汽的数量和质量进行综合的分析，是一个合理的评价和比较不同的蒸发方案的优劣的方法，而且具有简单快捷的优点。     

Efficiency of converting nutrient dry matter to milk in Holstein herds

Production of milk from feed dry matter intakes (DMI), called dairy or feed efficiency, is not commonly measured in dairy herds as is feed conversion to weight gain in swine, beef, and poultry; however, it has relevance to conversion of purchased input to salable product and proportion of dietary nutrients excreted. The purpose of this study was to identify some readily measured factors that affect dairy efficiency. Data were collected from 13 dairy herds visited 34 times over a 14-mo period. Variables measured included cool or warm season (high ambient temperature <21 degrees C or >21 degrees C, respectively), days in milk, DMI, milk yield, milk fat percent, herd size, dietary concentrations (DM basis) and kilograms of crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and forage. Season, days in milk, CP % and forage % of diet DM, and kilograms of dietary CP affected dairy efficiency. When evaluated using a model containing the significant variables, dairy efficiency was lower in the warm season (1.31) than in the cool season (1.40). In terms of simple correlations, dairy efficiency was negatively correlated with days in milk (r = -0.529), DMI (r = -0.316), forage % (r = -0.430), NDF % (r = -0.308), and kilograms of forage (r = -0.516), NDF (r = -0.434), and ADF (r = -0.313), in the diet, respectively. Dairy efficiency was positively correlated with milk yield (r = 0.707). The same relative patterns of significance and correlation were noted for dairy efficiency calculated with 3.5% fat-corrected milk yield. Diets fed by the herds fell within such a small range of variation (mean +/- standard deviation) for CP % (16.3 +/- 0.696), NDF % (33.2 +/- 2.68), and forage % (46.9 +/- 5.56) that these would not be expected to be useful to evaluate the effect of excessive underfeeding or overfeeding of these dietary components. The negative relationships of dairy efficiency with increasing dietary fiber and forage may reflect the effect of decreased diet digestibility. The results of this study suggest that managing herd breeding programs to reduce average days in milk and providing a cooler environment for the cows may help to maximize dairy efficiency. The mechanisms for the effects of the dietary variables on dairy efficiency need to be understood and evaluated over a broader range of diets and conditions before more firm conclusions regarding their impact can be drawn.     

Performance and health responses of dairy calves offered different milk replacer allowances

Eighty female Holstein calves (12 ± 4.1 d of age and 42 ± 4.3 kg of BW) were collected from different herds, brought to the study site, and blocked by age and assigned to either a 6 L/d maximum daily milk replacer (MR) allowance (LMR) or a maximum MR allowance of 8 L/d (HMR). Calves were kept in individual hutches until 52 d of age and then moved into pens, forming groups of 10. All calves had ad libitum access to a mash starter feed. Calves in both treatments received the MR distributed in 3 separate allotments between 1 wk after the beginning of the study and 52 d of age. Then, all calves were moved to group pens and preweaned by offering 2 L/calf of the same MR twice daily in a trough until the age of 59 d, when MR offer was further reduced to a single dose of 2 L until the age of 73 d, when all calves were completely weaned. Individual starter feed and MR consumption was recorded on a daily basis until 52 d of age, and on a group basis until weaning time. Body weight was measured at the beginning of the study and at 52 (preweaning), 73 (weaning), and 110, 160, and 228 d of age. Solid feed consumption (mean ± SE) was greater in LMR (821 ± 42.1 g/d) than in HMR calves (462 ± 42.1 g/d) between 42 d of age and 52 d (preweaning). As expected, as age increased, solid feed consumption increased, and LMR showed a more marked increase than HMR calves. Despite the greater solid feed intake of LMR calves, HMR grew faster than LMR calves until preweaning time, but from preweaning to weaning, LMR calves grew more than HMR calves (977 vs. 857 ± 30.7 g/d, respectively; mean ± SE). No differences in feed efficiency were observed. While calves were individually housed, no differences were observed in the incidence of bovine respiratory disease or diarrhea between treatment groups. We concluded that, under the milk regimen, age range of calves, and weaning method used in the current study, before preweaning, HMR calves grow more than LMR calves, but between preweaning and weaning, LMR grow more than HMR calves, overcoming the difference in BW at preweaning. As a result, with the weaning scheme followed herein, providing more milk does not ensure greater performance; no differences are obtained in BW at weaning and at 228 d of life. Also, based on solid feed consumption patterns seen in this study, we determined that the optimum age to reduce MR allowances and foster solid feed intake is around 45 d of age.     

江都县蚕业调查引起的思考

通过对江苏省江都县蚕业调查分析,揭示目前蚕业生产发展中的矛盾,并参照日本蚕业发展的历史过程,结合我国情况,提出解决方法。     

微生物检测有效性的保证要点

本文分析了做好微生物检测的几个要点,培养基有效性的校验、微生物监控体系的完善、检测人员素质水平和培训工作,这是确保微生物检测有效性的必要保证。     

磷钾肥对云南旱作马铃薯产量和养分吸收的影响--测试文章

在云南省曲靖地区的低肥力和中高肥力试验地分别开展旱作马铃薯的田间小区试验,研究磷钾施用量对马铃薯生物量、养分利用、产量和经济效益的影响。结果表明：相同施肥量的条件下,中高肥力试验地的东山组马铃薯产量远高于低肥力的越州组,产量相差10 305.00～20 140.20 kg·hm^-2;越州组NP2K3(N,150 kg·hm^-2; P₂O₅,90 kg·hm^-2; K₂O, 405 kg·hm^-2)处理产量产值最高,NP2K1(N,150 kg·hm^-2; P₂O₅,90 kg·hm^-2; K₂O, 135 kg·hm^-2)处理净收益最高; 东山组NP2K2(N,150 kg·hm^-2; P₂O₅,90 kg·hm^-2; K₂O, 270 kg·hm^-2)处理产量、产值及净收益均是最高; 两组试验的马铃薯干重变化趋势相似,NP2K2处理的干重积累量较多,无钾无磷处理干重积累少;马铃薯体内累积K最多,其次为N,最后为P, NPK养分吸收积累的高峰期在马铃薯块茎膨大期到淀粉积累期; 东山组的马铃薯PK利用效率明显高于越州组。NP1K2(N,150 kg·hm^-2; P₂O₅,45 kg·hm^-2; K₂O, 270 kg·hm^-2)处理的P肥利用率和P素农学效率较高,P肥利用率和P素农学效率都有随施P量增加而降低的趋势。NP2K1处理的K肥利用率和K素农学效率最高,K肥利用率和K素农学效率均有随施K量增加而降低的趋势。     

红外—喷动床联合干燥设备研制与分析

为较好地解决单一红外干燥均匀性差的问题,利用红外加热高效节能的特点,结合喷动床流动性好、传热均匀的特点,设计了红外联合喷动床干燥设备。该装置包括喷动床干燥系统、红外辐射加热系统、回风式空气调节系统、动力循环系统和控制系统等。并以新鲜毛豆为物料,对该装置干燥均匀性和产品品质进行试验验证。结果表明,单一红外干燥耗时270 min,而红外—喷动床联合干燥耗时160 min,与单一的红外干燥相比,红外—喷动床联合干燥时间缩短了40.7%;同时,红外—喷动床联合干燥设备减轻了毛豆仁干瘪皱缩现象,使干制品具有较好的豆香味和感官品质。     

克雷伯氏肺炎杆菌电击转化条件的优化

针对克雷伯氏肺炎杆菌(Klebsiella pneumoniae)TUAC01的电击转化方法进行了研究。主要考察了培养基EDTA的浓度、细胞的生长状态、感受态细胞的密度、电击电压、质粒浓度等参数对转化效率的影响,建立了一种适合K.pneumoniae TUAC01的电击转化方法。结果:K.pneumoniae TUAC01培养基中添加EDTA至终浓度0.7mmol/L;当细胞生长至OD600为0.7时收集菌体,制作感受态细胞;制作的感受态细胞浓度OD600大于30时,使用2mm的电转杯在2kV的电压下转化,转化效率达到最大值,达到8.58×105cfu/μg DNA。