The effect of grain species, processing and time of feeding on the efficiency of feed utilization and microbial protein synthesis in sheep

This study investigated the effect of cereal grain species (sorghum, wheat, oats and barley), extent of processing (cracked barley, finely ground barley, and wet whole barley) and time of feeding (barley grain mixed with ryegrass hay or fed 2 h before hay was fed), on whole tract dry matter digestibility (WTDMD), and microbial protein synthesis (MPS), as a supplement to ryegrass hay when fed to rumen-cannulated sheep.Expected dry matter digestibility (EDMD) in mixtures of cereal grain and ryegrass hay was calculated by interpolation between in vitro dry matter digestibility (DMD) of each grain and the ryegrass hay. These were compared with measured actual WTDMD to detect positive or negative associative effects. Among grain species, the percentage difference in digestibility between actual WTDMD and EDMD was negative at − 6.6% units for wheat but positive at + 2.3%, + 4.3% and + 5.7% units for sorghum, oats, cracked or finely ground barley, respectively.As expected, the supplementation of sheep fed ryegrass hay with different sources of carbohydrates increased urinary allantoin output (as an indicator of MPS) when compared to sheep fed ryegrass hay alone. The concentration of urinary allantoin was significantly higher in sheep supplemented with sorghum (1916 mg/sheep/day) than wheat, oats or cracked barley ([mean ± S.E.M.] 1451 ± 24 mg/sheep/day) grain. There was a significantly higher urinary allantoin concentration in sheep fed cracked barley compared to finely ground barley or wet whole barley (1479 vs. 1095 vs. 1031 mg/sheep/day, respectively). There was no significant (P > 0.05) difference in urinary allantoin output, expressed as output/kg DM intake, when cracked barley was mixed and fed with the hay or fed 2 h before hay. However, in terms of total output of allantoin this was significantly higher (P < 0.05) (1479 vs. 1209 mg/sheep/day).In sacco degradability characteristics of organic matter and nitrogen for sorghum, oats, wheat, barley at different levels of processing and for ryegrass hay were also measured in the rumen of cannulated sheep.Among grain species, wheat had the highest effective organic matter degradability in the rumen (78.1%) while sorghum had the lowest. The effective degradability of protein of finely ground barley in the rumen was found to be higher than cracked barley or wet whole barley.Wheat grain, being highly degradable in the rumen, had a negative effect on WTDMD. In contrast, sorghum grain, being more slowly degradable in the rumen, would be expected to provide a substantially increased supply of energy to microbes over time in the rumen for MPS.Both cracked barley and finely ground barley also had a positive associative effect on WTDMD when fed with ryegrass increasing it by 5.7% units. The MPS was significantly higher (P < 0.05) in sheep fed cracked barley compared to finely ground barley or wet whole barley. This supports the hypothesis that slowly degrading carbohydrate sources synchronise more closely with available N from degradation of forage in the rumen.     

Alfalfa as a supplement of dried cornstalk diets: Associative effects on intake, digestibility, nitrogen metabolisation, rumen environment and hematological parameters in sheep

The aim of the current study was to investigate the associative effects of a cornstalk-based diet supplemented with alfalfa (Medicago sativa) hay on intake, digestibility, nitrogen (N) metabolisation, rumen environment and hematological parameters in Xiaoweihan sheep. We also investigated the optimal range of alfalfa hay to achieve positive associative effects and avoid negative effects. Xiaoweihan sheep (n = 5; fitted with rumen T-cannula) were fed five cornstalk-based diets in a 5 × 5 Latin square design. Diets contained 0, 50, 150, 300, 450 g alfalfa, and were supplemented with 100 g concentrate, respectively. Our results suggested that supplementation of 300 g alfalfa hay reduced (P < 0.05) cornstalk intake, but significantly increased dry matter (DM) intake (P < 0.05). Additionally, DM digestibility of 150 g alfalfa hay supplementation was slightly higher than that noted in other diets. Metabolism studies showed 50–150 g alfalfa hay supplementation had a positive associative effect (P < 0.05) on N utilization, with the greatest benefit noted with 150 g per day (P < 0.05) compared to unsupplemented diets. Alfalfa supplementation (50–450 g per day) resulted in an elevated trend of ammonia nitrogen (NH₃–N) with 50 or 150 g of alfalfa hay more likely to promote sheep rumen environment, with a noticeable increase (P < 0.05) in serum urea nitrogen (UREAN) concentrations observed with 300 g alfalfa hay per day. Our data suggested that the optimal range to achieve beneficial effects and avoid negative effects was 150–300 g per day for cornstalk-based diets for sheep.     

大豆寡糖对瘤胃微生物区系的影响

本文旨在研究大豆寡糖对绵羊瘤胃细菌总数、纤维分解菌数、甲烷产生菌数和瘤胃原虫数的影响.选用9只带有永久性瘤胃瘘管的试验羊,随机分为3组,饲喂相同的基础日粮,并在此基础上分别灌注占干物质采食量(DMI)1.2%、0.6%和0.0%的大豆寡糖.细菌和纤维菌的计数采用Hungate的滚管法;甲烷菌的计数采用最大可能计数法进行;原虫计数采用血球计数室计数法.结果表明,灌注大豆寡糖提高了瘤胃纤维分解菌的数量,降低了甲烷产生菌的数量.这表明大豆寡糖对绵羊瘤胃微生物区系有着较为显著的影响,有利于中性洗涤纤维(NDF)在瘤胃内的降解和减少饲料能量的损失.     

奶牛瘤胃微生物的研究进展

奶牛的瘤胃中含有大量的微生物,这些微生物对奶牛的生产和健康具有重要意义,可以将日粮中的一些营养物质分解成微生物蛋白以及挥发性脂肪酸,为奶牛提供能量,维持其生产性能。测定奶牛瘤胃中的微生物变化,可以检测奶牛机体的变化,为奶牛疾病及代谢的诊断提供依据。此外,实现人工干预瘤胃菌群的组成,可以有效调控奶牛消化代谢,提高生产性能。本文归纳了奶牛瘤胃微生物的功能及其影响因素,介绍了瘤胃微生物移植方法及研究进展,以期为同行提供参考。     

鼠李糖乳杆菌对全株玉米青贮品质及瘤胃降解率的影响

本试验旨在研究鼠李糖乳杆菌(Lactobacillus rhamnosus GG,LGG)对全株玉米青贮品质及瘤胃降解率的影响。采用单因素试验设计,设置对照组(CON)和LGG处理组(添加105 CFU/g鲜重LGG),于0、24、36、48 d取样,测定其常规营养价值、发酵品质和瘤胃降解特性。结果表明:与CON组相比,LGG组干物质(DM)和粗蛋白质(CP)含量在48 d下降,中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)在36 d后显著降低,淀粉含量在36 d显著升高;不同天数的pH均显著下降;36 d和48 d乳酸含量显著升高,乙酸和丙酸在24 d时显著升高;氨态氮在整个发酵过程中变化不显著;LGG组DM慢速降解速率常数c和有效降解率(ED)均显著高于CON组;LGG组CP快速降解参数a、慢速降解速率常数c和ED显著升高,LGG组NDF慢速降解参数b和ED显著升高(P<0.05)。以上结果表明,鼠李糖乳杆菌能显著改善全株玉米青贮发酵品质,提高DM、CP和NDF在瘤胃内的ED。     

Anaerobic Fungal Diversity in the Rumen of Gayals (Bos frontalis) in Yunnan Province,China

To investigate the anaerobic fungal diversity in the rumen of gayals (Bos frontalis),Yunnan yellow cattle,yaks,and Tibetan yellow cattle,the ITS region of ruminal anaerobic fungi was sequenced.The anaerobic fungi found in four types of cattle could be divided into 16 groups (Neocallimastix,Anaeromyces,Orpinomyces,Caecomyces,Cyllamyces and unknown groups 1-11).There were 10 anaerobic fungal groups in the rumen of gayals,with three belonging to known genera (Orpinomyces,Neocallimastix,and Caecomyces),which accounted for 2.8％ of sequences of gayals.There were fewer known anaerobic fungi in gayals than in Yunnan yellow cattle (Orpinomyces),yaks (Anaeromyces,Orpinomyces,and Cyllamyces) and Tibetan yellow cattle (Anaeromyces,Orpinomyces,Caecomyces,and Cyllamyces),accounting for 30.7％,93.9％,and 35％ of each of the relevant cattle species.The other seven unknown groups (NG1,NG4,NG6,NG7,NG9,NG10,and NG11) accounted for 91.6％ of sequences from gayals,which was higher than Yunnan yellow cattle [69.3％ (NG2,NG8 and NG9)],Tibetan yellow cattle [35％ (NG4,NG5 and NG9)],and yaks [6.1％ (NG3)].Furthermore,NG1,NG6,NG7,NG10,and NG11 were only found in gayals,whereas NG3 and NG5 were found only in Tibetan yellow cattle and yak,respectively.Piromyces was not found in any of the four types of cattle.The anaerobic fungi abundance in the rumen of gayals was significantly higher than that of the other three types of cattle.The ruminal anaerobic fungi of gayals might have an important role in cellulose degradation,resulting in the ability of this species to successfully graze coarser fodder.     

日粮中添加棕榈油、玉米油对奶牛瘤胃发酵的影响

试验旨在研究日粮中添加棕榈油、玉米油对奶牛瘤胃指标的影响,试验采用3×3拉丁方设计,选择年龄、胎次、体重相近的安装永久性瘤胃瘘管健康荷斯坦牛3头。试验日粮分别是在基础日粮、基础日粮+200g棕榈油、基础日粮+200g玉米油;结果表明,棕榈油组、玉米油组各时间点pH值均高于对照组,但各组间差异没有达到显著水平(P0.05)。棕榈油组、玉米油组在不同时间点NH3-N浓度都略高于对照组,但差异均没有达到显著水平(P0.05)。添加棕榈油、玉米油对奶牛瘤胃液乙酸、丙酸、丁酸浓度变化的影响差异不显著(P0.05)。棕榈油组、玉米油组在各时间点DM的降解率均低于对照组,在24h时棕榈油组、玉米油组与对照组相比分别下降8.8%、14.0%,但差异均没有达到显著水平(P0.05)。棕榈油组、玉米油组和对照组的各时间点NDF、ADF降解率差异均不显著(P0.05)。说明添加棕榈油、玉米油对奶牛瘤胃发酵无显著不良影响。     

Technical note: A wireless telemetric method of monitoring clinical acidosis in dairy cows

Ruminant animals convert forage containing cellulose by bacterial fermentation into nutrients. The health of the bacterial culture in the rumen is essential for the health and productivity of the animal. Over a number of years fistulated animals have been used to study the rumen and its bacterial population. It has been shown that techniques to maintain the pH of the rumen between 7 and 5.5 pH are essential for the health of the dairy cow. The rumen pH has been recorded by using sensors suspended in the rumen at intervals or exceptionally with data recorders. However, fistulation of an animal requires surgery and is only suitable for a few research animals. This paper describes the development of a telemetric bolus that measured and recorded pH continuously. When interrogated by wireless the bolus transmitted the recorded data to an operator standing beside the cow with a receiving station. Boluses were placed in fistulated animals so that a comparison could be made with a laboratory instrument. Data are presented that show a close correlation between the calibrated laboratory instrument and the bolus at time intervals when the instrument was inserted. From this it can be assumed that the bolus accurately records the temporal variation in rumen pH. Data are presented to show the diurnal change in rumen pH over a 6-week period. Methods of increasing the lifetime and accuracy of the bolus are discussed.     

牦牛永久性瘤胃试验瘘管安置术

[目的]为研究反刍动物的消化功能提供参考。[方法]于2005年4月~2006年5月采用自创手术对15头2~3岁、体重为90~250kg的牦牛进行永久性人造瘤胃试验瘘管安置。[结果]手术后,所有施术牦牛精神状态、体温及食欲等方面均表现正常。7 d后检查发现,全部施术牦牛的瘤胃壁都与腹膜、腹肌及皮肤愈合在一起,形成自然瘘管,没有出现腹腔感染的现象。安置的的瘤胃试验瘘管都保持到1.5年以上。[结论]该手术方法具有过程简单,可操作性强,瘘管不易滑脱,密闭性好,创口恢复快、无感染,没有瘤胃液渗出和感染现象等优点,术后牦牛能正常存活,可长期用于试验。