Direct and Residual Contributions of Symbiotic Nitrogen Fixation by Legumes to the Yield and Nitrogen Uptake of Maize (Zea mays L.) in the Nigerian Savannah

Field experiments were conducted to determine the direct and residual contributions of legumes to the yield and nitrogen (N) uptake of maize during the wet seasons of 1994 and 1995 at the University Farm, Abubakar Tafawa Balewa University, Bauchi, Nigeria, located in the Northern Guinea savannah of Nigeria. Nodulating soybean, lablab, green gram and black gram contributed to the yield and N uptake of maize either intercropped with the legumes or grown after legumes as a sole crop. Direct transfer of N from the nodulating soybean, lablab, green gram and black gram to the intercropped maize was 24.9–28.1, 23.8–29.2, 19.7–22.1 and 18.4–18.6 kg N ha^–1, respectively. However, the transfer of residual N from these legumes to the succeeding maize crop was 18.4–20.0, 19.5–29.9, 12.0–13.7 and 9.3–10.3 kg N ha^–1, respectively. Four years of continuous lablab cropping resulted in yields and N uptake of the succeeding maize crop grown without fertilizer N that were comparable to the yields and N uptake of the succeeding maize crop supplied with 40–45 kg N ha^–1 and grown after 4 years of continuous sorghum cropping. It may therefore be concluded that nodulating soybean, lablab, green gram and black gram may be either intercropped or grown in rotation with cereals in order to economize the use of fertilizer N for maize production in the Nigerian savannah.     

Vaccination of the brushtail possum (Trichosurus vulpecula) against Mycobacterium bovis infection with bacille Calmette-Guérin: the response to multiple doses.

In New Zealand, the brushtail possum (Trichosurus vulpecula) is the principal wildlife vector of bovine tuberculosis. Control of infected possum populations contributes to the control of tuberculosis in domestic livestock. Vaccination is potentially a complementary strategy to population control, but to be cost-effective, administration of the vaccine to possums would need to be from an appropriately designed automatic vaccinator. Possums themselves would activate the vaccinator so that it would deliver an aerosol spray of vaccine. There would be no direct way to prevent possums receiving multiple doses of vaccine. This study examined the effect on protective immunity of repeated vaccination. Captive possums were vaccinated with BCG strain pasteur 1173P2 either 12 times at weekly intervals, twice at 6-weekly intervals, or once. Vaccination was by a combination of intranasal aerosol and conjunctival instillation. Eight weeks after the last dose of vaccine, all possums were challenged intratracheally with Mycobacterium bovis strain 83/6235. Vaccination induced a significant immune response as measured by the lymphocyte proliferation assay (LPA). A significant level of protection, as measured by the response to challenge, developed in all the vaccinated possum groups, but protection was greatest in the group vaccinated 12 times. It was concluded that protection would be enhanced if vaccinations were repeated at short intervals (weekly), but no benefit or detriment resulted from revaccination after longer intervals (1-2 months).     

Use of synthetic peptides in virology

A survey of the potential use of synthetic oligopeptides in the field of virology is given. The potential value of synthetic peptides as vaccines and diagnostic antigens is discussed. The advantages compared to conventional vaccines as well as the limitations, e.g. the poor efficiency of immune response, are described.     

Gas exchange in swine before, during and after motor activity of different intensity and length

4 female and 2 male untrained fattening pigs, weighing 43.9 +/- 1.6 kg at the beginning of the experiment underwent continuous measurement of VO2, VCO2, and rectal temperature, prior to, during, and after running on a horizontal exercise belt set to speeds of 0.7, 1.3, and 2.5 m.s-1. The highest values of VO2 and VCO2 (ml-min-1/kg-1) and rectal temperature (degrees C) were usually measured few minutes after running. They were 18.84 +/- 3.65 and 20.4 +/- 4.53 as well as 41.2 +/- 0.4, 28.41 +/- 4.07 and 33.26 +/- 5.92 or 41.3 +/- 0.5, 26.21 +/- 7.7 and 32.32 +/- 7.14 as well as 40.5 +/- 0.7, depending on the above belt speeds. Exercise belt speeds of 1.3 to 1.8 m.s-1 were found to be suitable for testing aerobic metabolic capacity of untrained young pigs.     

Einfluß von nutritiven Faktoren während einer Lernphase auf die Entstehung eines spezifischen Lysinhungers bei Legehennen

Bei 72 einzeln gehaltenen Legehennen wurde die Fähigkeit zur selektiven Lysinaufnahme überprüft. 2 unterschiedliche Alleinfutter auf der Basis von Federmehl (A) oder Maiskleber (B), aber mit dem gleichen defizitären Lysingehalt (0,36%), wurden während einer zweiwöchigen Lernphase jeweils an eine Hälfte der Tiere verfuttert. Anschließend wurden beide Vorbehandlungen in je 4 Gruppen geteilt, und eine der Mangelrationen und eine mit Lysin bedarfsgerecht supplementierte Ration (A+ bzw. B+, 0,64%) in folgenden Kombinationen zur Selbstauswahl über 14 Tage angeboten: A/A+, A/B+, B/A+ und B/B+. Über den prozentualen Rationsanteil am Gesamtfutterverzehr wurde die selektierte Lysinaufnahme ermittelt. Mit beiden Mangelrationen wurde eine Anorexie und in Folge eine Leistungsdepression ausgelöst, die jedoch bei B stärker ausgeprägt war. Die lysinangereicherte Ration wurde in fast allen Fällen innerhalb weniger Tage signifikant und stetig zunehmend bevorzugt, was für einen erlernten Lysinappetit bzw. -hunger spricht. Gleichzeitig wurde eine deutlichere Präferenz für die Federmehlration beobachtet, die bei Gruppe A/B+ nach B sogar zu einer Ablehnung der ergänzten Maiskleberration führte. Vertrautheit bzw. Neuartigkeit und sensorische Qualitäten einer Ration spielten neben den physiologischen Effekten eine bedeutende Rolle bei der Selbstauswahl. Die komplexen Wechselbeziehungen zwischen Futter, hedonistischen Komponenten und Erfahrung für die Entwicklung eines spezifischen Hungers wurden diskutiert.     

The cervical vertebral column of horses--a clinico-radiological study

For various anamnestic reasons the cervical vertebral column of 78 horses was examined radiologically. Statistical comparisons showed that male "warmbloods" were more frequently affected than was expected. Our horses were older than comparable animals in the international literature. Independently of their history the radiologic diagnosis of "cervical spondylarthrosis" was established in 56 horses. Arthrosis and other conditions were clinically manifested by spinal ataxia (44 horses) or mechanical impairment of the neck's mobility (21 horses). 10 of the arthrotic patients had synovial cysts causing compression of the spinal cord. 79 percent of all dorsal intervertebral arthrotic joints were found in the caudal column (C6/7 to C7/Th1). With 38 percent, C6/7 was the most frequently affected joint. Clinical and radiological findings could be compared with patho-anatomic results in 29 horses. The correlation was satisfactory.     

Implications of using an average relationship matrix in genetic evaluation for a population using multiple-sire matings

SUMMARY: Ambiguous paternity can be incorporated into the mixed model equations (MME) by including the average numerator relatinship matrix (average A), which averages the true sire-offspring relationship over the putative sires. A previous study has shown that some overestimation of genetic trend results from this substitution. A population of 40 breeding females and 2 breeding males was simulated 1,000 times with either random mating or sequential selection continuing for 8 breeding cycles. In the selection case candidates were ranked on estimated breeding values (EBVs) calculated from the MME with an animal model and the average A. Variances of the EBVs and prediction errors were computed. The results showed the average A incorrectly perceives both the variance of family sizes among males and the variance loss due to selection to be smaller. This will lead to an overestimation of genetic trend. ZUSAMMENFASSUNG: Folgerungen aus der Anwendung einer durchschnittlichen Verwandtschaftsmatrix bei der Zuchtwertsch?tzung für eine Population mit mehreren V?tern in einer Paarungsgruppe In den Mischmodellgleichungen kann eine unklare v?terliche Abstammung durch die Verwendung einer durchschnittlichen Verwandtschaftsmatrix, die die Abstammung zu gleichen Teilen über die m?glichen V?ter aufteilt, berücksichtigt werden. Eine frühere Arbeit hat gezeigt, da? diese Ma?nahme zu einer gewissen übersch?tzung des genetischen Fortschritts führt. Eine Population mit 40 weiblichen und 2 m?nnlichen Tieren wurde 1000mal über 8 Paarungsperioden simuliert und zwar mit und ohne gerichteter Selektion. Im Falle der Selektion wurden die Tiere aufgrund der mit einem Tiermodell und der durchschnittlichen Verwandtschaftsmatrix gesch?tzten Zuchtwerte geordnet. Die Varianzen der Zuchtwerte und der Sch?tzfehler wurden berechnet. Die Ergebnisse zeigen, da? durch eine durch-schnittliche Verwandtschaftsmatrix die Varianz der Gr??e der Nachkommensgruppen der V?ter und der Verlust an genetischer Varianz aufgrund der Selektion untersch?tzt wird. Dies führt zu einer übersch?tzung des genetischen Fortschritts.     

Studies of cardiac pathomorphology in swine which died during transport

The following findings were obtained from pathomorphological examination of the myocardium of 100 pigs which had died on transport: Degenerative or necrobiotic changes of certain myocardial fibres were recorded from 73 per cent of all cases, usually in the form of granular degeneration (60 per cent). They were "scattered" in 33 per cent of all cases, "multiple" in 22 per cent, and "frequent" in five per cent. In 26 per cent, the myocardial fibres had undergone coarse granular or hyalin plaque-type decomposition, among them with "scattered" manifestation in 15 per cent, "multiple" in four per cent, "frequent" in five per cent, and "massive" in two per cent. Moderate focal resorptive myositis was recorded from eight per cent, while earlier myocardial scars were exhibited by four per cent. The figure for reactive inflammatory processes was twelve per cent. Prestatic hyperaemia of different degrees had taken place in 75 per cent of all animals, and it had been accompanied by varied congestion. The following results were obtained from comparative checks of 100 hearts of clinically intact pigs after slaughter under normal conditions: Granular degeneration was recorded only from 18 per cent of all cases, with actual manifestations "scattered" in 16 per cent and "multiple" in two per cent. Their myocardial fibres had undergone coarse granular or hyalin plaque-type decomposition of moderate intensity in three per cent only, all of them having been "scattered". Reactive inflammatory changes were not recorded at all and signs of prestatic hyperaemia only in 46 per cent. The degenerative-necrobiotic alterations of myocardial fibres which had been observed in the context of death on transport are interpreted as a result of hypoxaemic or hypoxic conditions accompanying acute shock-type circulatory failure in pigs.