在放牧干扰下冷蒿种群脯氨酸含量的变化

对放牧干扰下土壤含水量、冷蒿体内含水量、脯氨酸含量变化进行的研究结果表明随着放牧强度的增加土壤含水量降低,冷蒿叶片、根中含水量呈下降趋势。在生长初期,随着放牧强度的增加冷蒿叶片内脯氨酸含量迅速积累;生长盛期脯氨酸含量虽随牧压有所增加,但增加的幅度较小;生长末期脯氨酸含量较高,而且随着牧压的增加略有下降。地下部分,脯氨酸含量在牧压梯度间变化较小。相关分析表明,在生长初期和盛期,冷蒿叶片、根的含水量与土壤含水量呈正相关,生长末期不相关。冷蒿脯氨酸含量与植物的含水量呈负相关,在生长初期和末期呈显著负相关,而生长盛期相关不显著;与此不同,在生长初期冷蒿体内脯氨酸含量与土壤含水量呈负相关,在生长末期二者负相关性不显著,这说明随着放牧干扰强度的增加土壤含水量降低,导致冷蒿体内水分胁迫增加,致使脯氨酸开始逐渐积累。而生长末期的降温和群落中植物种间竞争减少,使脯氨酸的积累速度也相应放慢。在放牧干扰下,脯氨酸大量积累,对冷蒿的生存和生长起到了重要的作用,是冷蒿种群耐啃食、耐践踏、逐渐取代禾本科植物而成为退化草原的优势植物的生理基础之一。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Lack of mutagenicity of fasciolicides

Six fasciolicides, bithionol, bromofenofos, DS-6, nitroxynil, oxyclozanide and tribromsalan, were tested for mutagenicity in the Salmonella reverse mutation test using S. typhimurium tester strains TA100, TA98, TA1535, TA1537 and TA1538 and the micronucleus test in mice. None of the fasciolicides increased the number of revertant colonies in any tester strain in the presence and absence of S9 mix, nor did they induce a significant increase of the micronuclei in erythrocytes. Taking the high correlation between mutagenicity and carcinogenicity into consideration, these results suggest that the fasciolicides tested in this investigation are devoid of carcinogenic action.     

Parasites of the stomach in donkeys of the highveld of Zimbabwe

Fourteen donkeys from a communal area of the Zimbabwean highveld were examined for stomach parasites during July and November of 1986 and January and April of 1987. All 14 animals were infected. Habronema muscae occurred in 12, Draschia megastoma in 11, H. majus in 9, Trichostrongylus axei in 9, Gasterophilus intestinalis in 14 and G. nasalis in 1 donkey. The lowest level of infection was in January for the helminths and in April for Gasterophilus larvae. The peak burdens of parasites were in July for Habronema spp. and in November for D. megastoma and Gasterophilus larvae. Infections with spirurid worms and Gasterophilus develop mainly from the middle of the rainy season to the beginning of the dry season (January to May/June). G. intestinalis seems to have an annual cycle.     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

母猪繁殖障碍疾病的原因分析及防制

母猪繁殖障碍疾病在各种猪场都有不同程度的发生,该病已成为大中型猪场重要疾病。母猪繁殖障碍综合征发生的原因多而复杂,有传染性因素、寄生虫性因素、非传染性因素,但对于规模化养猪场来讲,传染性疾病是猪繁殖障碍的主要原因。母猪繁殖障碍造成的经济损失严重,因而有必要对发病原因进行分析,阐述流行及主要表现,制定合理免疫程序,提出综合防制措施。     

雏鸡喹乙醇中毒血液生化指标测定

为探讨喹乙醇急性中毒雏鸡血液生化指标的变化情况,。将200只5日龄伊莎公鸡雏随机分为2组,对照组饲喂基础饲粮,试验组饲喂基础饲粮+150mg/kg喹乙醇。在染毒后5、10、15d,对相关血液生化指标进行检测。结果表明,喹乙醇中毒时,在各时间点,试验组血清K+含量均高于对照组,在15d差异显著(P<0.05);试验组血清中Ca2+、PO43-、Na+含量均低于对照组,在15d差异均显著(P<0.05);试验组血清ALB、TP含量均低于对照组,ALB在15d差异显著(P<0.05),TP在10d和15d差异显著(P<0.05);试验组血清ALP、GOT、GPT活性高于对照组,GOT、GPT在15d差异显著(P<0.05)。结果显示喹乙醇中毒能够引起雏鸡相关血液生化指标的改变,喹乙醇有一定的蓄积毒性。     

论我国企业跨国并购中的薪酬整合问题

随着我国经济的持续增长,我国企业已经迈出了跨国并购的步伐,但是由于地区间文化与制度的差异,导致了我国企业跨国并购整合困难重重,其中尤以薪酬整合为甚为棘手。如何整合薪酬已成为我国企业跨国并购中的关键问题之一。文中就我国企业跨国并购中遇到的薪酬问题进行了讨论,并从战略的角度出发讨论了我国企业跨国并购的薪酬整合过程,即：全面薪酬调查、制定匹配的薪酬战略薪酬战略的有效实施。     

气味丰容对几种蛇类行为影响实验

2010年3月～11月,在成都动物园两爬馆饲养展出蛇类中选取了缅甸蟒、缅甸白蟒、加州王蛇和三色乳蛇等进行了不同气味丰容实验并对气味丰容前后蛇类自主活动行为进行观察比较。其中对缅甸白蟒和缅甸蟒均采用了兔子血、茶叶包进行气味丰容;对加州王蛇和三色乳蛇均采用了小白鼠、茶叶包进行气味丰容。实验结果表明,通过不定期采用不同气味对蛇类进行丰容刺激,可以显著改善蛇类的自主活动情况,从而提高蛇类的观赏展示效果,也有利于改善蛇类的健康状况。气味丰容方案可以在其他蛇类的饲养展出中进行推广应用。     

不同类型黑麦草营养价值评估

文章旨在通过体内外试验评估不同类型黑麦草的营养价值。试验选择平均体重为（66.87±2.34）kg的绵羊12头,随机分成3组,每组4个重复,每个重复1头。3组绵羊分别饲喂新鲜、青贮和晒干黑麦草。经过14?d的饲养试验后收集粪便和牧草样品进行后续分析。结果：晒干黑麦草的干物质、有机物和无氮浸出物含量均表现最高（P＜0.05）。新鲜黑麦草粗蛋白质和半纤维素含量较青贮黑麦草分别显著提高42.10%和10.82%（P＜0.05）。青贮黑麦草粗脂肪、粗纤维、中性洗涤纤维和酸性洗涤纤维含量显著高于其他两种类型的黑麦草（P＜0.05）。新鲜、青贮和晒干黑麦草的粗蛋白质、粗脂肪和粗纤维表观消化率无显著差异（P＞0.05）。晒干黑麦草干物质表观消化率较新鲜和青贮黑麦草显著提高6.34%和6.21%（P＜0.05）,同时晒干黑麦草有机物表观消化率较新鲜黑麦草显著提高6.65%（P＜0.05）,无氮浸出物表观消化率较青贮黑麦草显著提高15.44%（P＜0.05）。当体外代谢能值以MJ/kg有机物表示时,新鲜和青贮黑麦草代谢能值较晒干黑麦草分别显著提高21.34%和22.41%（P＜0.05）,而当体外代谢能值以MJ/kg干物质表示时,新鲜黑麦草能值最高,青贮黑麦草能值次之,晒干黑麦草能值最低（P＜0.05）。结论：新鲜、晒干和青贮黑麦草在不同营养成分上各有优势,但3种牧草主要营养物质的表观消化率和代谢能值无显著差异。因此,无论是新鲜、晒干还是青贮黑麦草都可以作为反刍动物粗饲料的良好来源。 [关键词]黑麦草;青贮;营养价值;消化     

重构胚移植用受体山羊同期发情处理效果比较

分别用CIDR（孕酮阴道栓）＋PMSG（处理1）和CIDR＋PMSG＋LH（处理2）两种处理方法对山羊进行同期发情处理。结果发现,两种处理均以撤栓后第1d发情率最高。撒栓后0-24h和24h-48h的发情率,处理1和处理2（61．4％,13．6％和48％,20％）之间差异不显著;撤栓后48h-72h的发情率,处理1（4．59,6）显著低于处理2（24％）（P〈0．05）;撤栓后0～72h发情率,两种处理（79．5％,92％）无显著差异（P〉0．05）。从手术时对卵巢的观察可以看出,有大卵泡或排卵的发情羊,处理1为91．2％,处理2为100％,二者无显著差异;排卵的发情羊,处理1为（58．8％）显著低于处理2为（91．2％）（P〈0．05）。     

Survival of infective larvae of nematode parasites of cattle during drought

In a study originally designed to determine the seasonal origin of the high levels of availability of nematode larvae to cattle in winter and spring, plots were serially contaminated with eggs of Ostertagia ostertagi and Cooperia oncophora by naturally-infected calves at monthly intervals from February 1980 to September 1980. The availability of infective larvae was monitored by monthly pasture sampling and larval recovery. Because of the intervention of a 15 month drought, recoveries of larvae from the pastures were very low until March 1981 (autumn in Australia) when large numbers of larvae appeared on pastures contaminated in the preceding spring. Examination of dry dung pats at that time showed that significant numbers of larvae were present in pats deposited up to a year previously, and particularly in pats deposited in May, August and September. Following the resumption of normal rainfall in May 1981, larval numbers in pats rapidly declined and concentrations of larvae on the pastures increased to extremely high levels. It is suggested that survival of infective larvae in dry dung pats was enhanced by the drought, with implications for control of nematode infections of cattle, particularly in winter rainfall environments.     

Effect of rate of induction of carbon dioxide anaesthesia on the time of onset of unconsciousness and convulsions

The effect of different rates of induction of carbon dioxide anaesthesia on the time to loss of consciousness was investigated in broilers and hens. In experiment 1, 24 and 17 broilers, respectively, were exposed to 45 per cent carbon dioxide within 8 or 18 seconds (accession time). In experiment 2, 18 to 20 broilers and hens were exposed to either 35, 45, 55 or 65 per cent carbon dioxide within 8 seconds. The results indicated that, in general, the rate of accession is more critical than the final concentration of carbon dioxide; however, in 35 per cent carbon dioxide an exposure time of longer than 5 minutes is required to kill the birds. The time to sustained eye closure, time to onset of clonic and tonic convulsions and the duration of convulsive episodes were shorter in broilers than in hens. It is suggested that under commercial situations a final concentration of 55 per cent carbon dioxide would be suitable for killing broilers and hens.     

Sites of persistence of feline calicivirus

Various tissues were collected from eight cats persistently infected with feline calicivirus (FCV) strain 255 to determine the sites of viral persistence. Tissues were tested by virus isolation and an immunohistochemical technique in which infected cells were detected in formalin-fixed, paraffin-embedded tissue sections using rabbit antiserum to FCV 255, a biotinylated second antibody and streptavidin-peroxidase. Virus was detected by one or both techniques in tonsillar tissues of each animal, and not in other samples. Infected cells were detected in samples from six of eight kittens, and in each animal were few in number, and were cells of the superficial tonsillar epithelium or the stratum germinativum of the adjacent fossa mucosa. Transmission electron microscopic examination of tissues from three of the cats revealed calicivirus-like particles in cells similar to those identified immunohistochemically. These results confirm that the tonsillar region is the major site of FCV persistence and indicate that virus replication during persistence is confined to the surface epithelium of the tonsil and adjacent fossa mucosa.     

Effects of application in spring of urea fertiliser on aspects of reproductive performance of pasture-fed dairy cows

AIMS: To assess if raising concentrations of crude protein (CP) in pasture in spring by the frequent application of urea fertiliser would affect ovarian follicular dynamics, luteal function, onset of oestrus and reproductive performance of dairy cows under farming conditions in New Zealand. METHODS: Spring-calved dairy cows were grazed for 101 days in paddocks that were either not fertilised (Control; n=20) during the course of the study, or were fertilised with 40-50 kg nitrogen (N)/ha every 4-6 weeks (High-N; n=20). Similar generous pasture allowances were offered to both groups. Concentrations of CP in pasture, urea in serum and progesterone in milk were measured. Ovarian follicular and luteal dynamics were determined using ultrasonography. Oestrous behaviour and the number, time and outcome of inseminations were also recorded. RESULTS: Mean concentrations of CP in pasture and urea in serum was higher in the High-N than the Control group (25.2 vs 21.6 and 8.3 vs 5.4 mmol/L for CP and urea, respectively; p<0.001). Intervals between calving and first oestrus, first insemination and conception, the time of first emergence of a dominant follicle, milk progesterone concentration, and the diameter of the corpus luteum (CL) in the first luteal phase did not differ significantly between groups. The interval from calving to first ovulation tended (p=0.10) to be lower and the diameter of the dominant follicle of the oestrous cycle at which cows conceived was greater (p=0.02) in Control than High-N cows. CONCLUSIONS: The use of large amounts of urea fertiliser during spring and the consequent increases in concentrations of CP in pasture and urea in serum did not negatively affect any of the parameters of reproductive performance of pasture-fed dairy cows that were assessed in this study.     

Parasites of the stomach in donkeys of the highveld of Zimbabwe

Summary

Fourteen donkeys from a communal area of the Zimbabwean highveld were examined for stomach parasites during July and November of 1986 and January and April of 1987. All 14 animals were infected. Habronema muscae occurred in 12, Draschia megastoma in 11, H. majus in 9, Trichostrongylus axei in 9, Gasterophilus intestinalis in 14 and G. nasalis in 1 donkey. The lowest level of infection was in January for the helminthes and in April for Gasterophilus larvae. The peak burdens of parasites were in July for Habronema spp. and in November for D. megastoma and Gasterophilus larvae. Infections with spirurid worms and Gasterophilus develop mainly from the middle of the rainy season to the beginning of the dry season (Januari to May/June). G. intestinalis seems to have an annual cycle.     

Diagnostic value of cytology of bronchoalveolar fluid for lung diseases of sheep

Bronchoalveolar lavage fluid was collected postmortem from the lungs of 113 sheep, and total and differential cell counts were analysed in relation to the presence of gross and microscopic lung pathology. The diffuse lung diseases, maedi and adenomatosis, were both characterised by an increase in overall cellularity and by increases in the percentages of lymphocytes and neutrophils, respectively. Focal parasitic lung disease was characterised by an increase in the percentage of eosinophils and mast cells. Consolidated lung lesions were characterised by a slight increase in cellularity but no change in the differential cell profile. In regions of parasitised and consolidated lungs without lesions the differential cell profile was consistent with focal lung pathology, although the slight increase in cellularity observed in the consolidated regions was not observed in the regions without lesions. A decision tree was developed to facilitate the interpretation and indicate the likely predictive capacity of the differential cytology of the fluid.     

Lack of mutagenicity of fasciolicides

Six fasciolicides, bithionol, bromofenofos, DS-6, nitroxynil, oxyclozanide and tribromsalan, were tested for mutagenicity in theSalmonella reverse mutation test usingS.typhimurium tester strains TA100, TA98, TA153, TA1537 and TA1538 and the micronucleus test in mice. None of the fasciolicides increased the number of revertant colonies in any tester strain in the presence and absence of S9 mix, nor did they induce a significant increase of the micronuclei in erythrocytes. Taking the high correlation between mutagenicity and carcinogenicity into consideration, these results suggest that the fasciolicides tested in this investigation are devoid of carcinogenic action.     

一日龄大通牦牛和平原黄牛骨骼肌显微结构的比较

为了探讨1日龄大通牦牛骨骼肌组织学特点及对低氧的适应,以平原黄牛为对照,利用光镜和计算机图像分析系统测定骨骼肌肌纤维直径、表面积密度;通过透射电镜比较骨骼肌线粒体的面数密度、面积密度、体积密度、平均体积等结构参数。结果显示,1日龄大通牦牛骨骼肌肌纤维直径显著细于1日龄平原黄牛,表面积密度明显大于平原黄牛,差异极显著(P<0.01);1日龄大通牦牛骨骼肌细胞中线粒体平均体积小于1日龄平原黄牛,并具有极显著差异(P<0.01);而1日龄大通牦牛骨骼肌细胞中线粒体体积密度、面积密度、面数密度均大于1日龄平原黄牛,且差异极显著(P<0.01)。以上结果表明,大通牦牛通过增加骨骼肌线粒体面数密度、面积密度、体积密度,降低线粒体平均体积来提高其在低氧环境中对氧的利用,并且在长期进化中形成了肌纤维直径小,表面积密度大的组织学特点。     

C-reactive protein in monitoring and evaluation of effects of therapy of the MMA syndrome of sows

The elevated concentration of CRP in sows at the early stage of the MMA reflected the inflammation in the reproductive tract and in the mammary gland. Monitoring the level of CRP during the first days after parturition may be used to diagnose early stages of the MMA and to start therapy. In the treated MMA sows the level of CRP steadily decreased, and by the end of the experiment it had returned to the normal level. In the non-treated MMA sows CRP persisted at a high level and at day 10 of the experiment it was 13 times higher than in the treated animals and 16 times higher than in controls. Measurements of serum CRP are valuable in monitoring the health status of sows after parturition and should be introduced as the diagnostic method of the MMA syndrome in sows. The determination of the concentration of serum CRP during the first two days after parturition should be used for diagnosis of the early stages of MMA syndrome in sows and to start therapy when clinical symptoms of MMA are still absent.