Effective rumen degradation of dry matter, crude protein and neutral detergent fibre in forage determined by near infrared reflectance spectroscopy

The objective of the present study was to examine if near infrared reflectance spectroscopy (NIRS) could be used to predict degradation parameters and effective degradation from scans of original forage samples. Degradability of dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF) of 61 samples of perennial ryegrass (Lolium perenne L.) and orchardgrass (Dactylis glomerata L.) was tested by using the in situ technique. The grass samples were harvested at three different stages, early vegetative growth, early reproductive growth and late reproductive growth. Degradability was described in terms of immediately rumen soluble fraction (a fraction, for DM and CP only as NDF does not contain a soluble fraction), the degradable but not soluble faction (b fraction) and the rate of degradation of the b fraction (c value). Overall effective degradability of DM, CP and NDF was also calculated. Near infrared reflectance spectroscopy was examined for its ability to predict degradation parameters and to make a direct prediction of effective degradation from scans of the original samples of perennial ryegrass and orchardgrass. Prediction of effective degradation of the different feed fractions showed different accuracy. The coefficients of determination (R(2)) from regressions of predicted vs. measured effective degradation, using a cross-validation method, were 0.92 for DM, 0.78 for CP and 0.61 for NDF. The attempt to predict the degradation parameters (a, b and c) by NIRS was less successful as the coefficients of determination for the degradation parameters were low. Concentrations of CP and NDF in the original samples were predicted by using NIRS and the validated R(2) value was 0.98 for CP and 0.92 for NDF. It is concluded that using NIRS predictions from scans of original samples is a promising method to obtain values for the effective degradation of DM, CP and NDF in ruminant feeds, but that larger calibration sets are necessary for obtaining improved accuracy.     

Bacteriuria in cats with feline lower urinary tract disease: a clinical study of 134 cases in Norway

Feline lower urinary tract disease (FLUTD) is considered to be one of the most common diagnoses in feline patients. Several authors have concluded that feline idiopathic cystitis is the most common cause of FLUTD, whereas infectious cystitis is diagnosed in only 2% of the cases. In the period from January 2003 to February 2005, 134 cats that presented with signs of lower urinary tract disorders were included in a study at the Norwegian School of Veterinary Science. Ninety-seven percent were first opinion cases. All the cats went through a physical examination, and blood samples were collected for haematology and clinical chemistry. The urine analysis included urine stix, specific gravity, microscopic examination of the sediment and microbiological culturing. The urine samples were collected as voided mid-stream urine samples, by catheter or by cystocentesis and the method used was registered. Of the 134 cats included in the study, 37% were diagnosed as having obstructive and 63% as having non-obstructive FLUTD. In total 44 cats (33%) were diagnosed with bacteriuria, exceeding 10(3) colony forming units per millilitre (cfu/ml) and 33 (25%) of these cats had bacterial growth exceeding 10(4) cfu/ml, either alone or in combination with crystals and/or uroliths. Six cats (18%) with bacterial growth exceeding 10(4) cfu/ml were older than 8 years. No significant difference was found between the sampling methods performed with regard to bacteriuria. This study indicates that bacteriuria may have been underdiagnosed in Norwegian cats with clinical signs of FLUTD. It also confirms the importance of microbiological culturing in first opinion cases with FLUTD and that a skilled operator can get representative samples regardless the choice of method.     

Evaluation of three serological tests for brucellosis in naturally infected cattle using latent class analysis

Serological methods are traditionally used in diagnosis of brucellosis. However, the comparative performance of these tests and their accuracy under the local environment in Zambia has not been assessed. Thus, the objective of our study was to evaluate the diagnostic performance of three serological tests for brucellosis; Rose Bengal Test (RBT), competitive ELISA (c-ELISA) and Fluorescence Polarisation Assay (FPA) in naturally infected cattle in Zambia without an appropriate reference test to classify animals into truly infected and non-infected. Serological test results from a study to determine sero-prevalence were used to compare the performance of RBT, c-ELISA and FPA in diagnosing brucellosis in traditional cattle. Since none of the tests can be seen as a perfect reference test or gold standard, their performance in a population of naturally infected cattle was evaluated using latent class analysis which allows the sensitivity (Se) and specificity (Sp) to be estimated in the absence of a gold standard. The highest Se was achieved by the c-ELISA (97%; Credible Posterior Interval (CPI)=93-100%) and the highest Sp by the FPA (93%; CPI=85-99%), conversely these tests also had the lowest Sp and Se, respectively, with the RBT performing well in both the Se (93%; CPI=84-98%) and Sp (81%; CPI=61-97).     

The effect of oxygen and carbon dioxide concentrations on bacterial soft rot of potatoes. I. King Edward potatoes inoculated withErwinia carotovora var.atroseptica

Summary MatureKing Edward potatoes were wounded, inoculated withErwinia carotovora var.atroseptica and stored at +10°C and 100% r.h. in controlled concentrations of oxygen and carbon dioxide for up to 18 days. After incubation in air or in 5% O₂ in N₂ rots were brown, dry and restricted; more extensive, soft spreading rots were produced in potatoes stored in 5% O₂+16% CO₂, in 1% O₂+20% CO₂, in 1% O₂ and in N₂, the most extensive rots occurring in the anaerobic conditions. In addition toE. carotovora var.atroseptica, pectolytic clostridia could also be recovered from the spreading rots. The experiments demonstrate the extent to which the concentration of oxygen and carbon dioxide in the environment may effect the sensitivity of tubers to bacterial attack.     

Influence of daylength and temperature during formation of seed potatoes on subsequent growth and yields under long day conditions

Production of high quality seed potatoes is normally favoured by a cool climate with minor pest problems. Growth chamber studies aimed to reveal if daylengths (12 and 24 hrs) and temperatures (18/12 and 12/9°C day/night) during production also might influence progeny growth. Results showed no significant carry-over effect from daylength conditions, while growth vigour and yields were affected by parent plant growth temperature. Further experiments, including a greater range of temperatures, different cultivars and measurements of physiological age, are required to discuss theoretical and practical implications of the results.     

Factors influencing the soft-rotting of potato tubers by bacteria

Summary The production of extensive soft rot in potato tubers which were wounded, inoculated withErwinia carotovora var.atroseptica and stored inc. 100% RH at 20° was greatly increased by replacing air in containers with N₂. Accumulation of CO₂ due to tuber respiration did not significantly affect the production of rots in these conditions. When tubers were inoculated with sterile water in place of theErwinia and held under anaerobic conditions, spreading soft rots were also produced andClostridia, but not soft rotErwinia, were isolated from the rotted tissue. Some of theseClostridia were shown to be capable of breaking down potato tissue, and may be a significant cause of potato soft rots developing in store.     

A method of testing the effect of antibacterial compounds on bacterial soft rot of potatoes,and results for preparations of dichlorophen and sodium hypochlorite

Summary A product containing dichlorophen as the main active ingredient was bacteriostatic against, strains ofErwinia carotovora and pectolytic clostridia in culture at concentrations equivalent to 25 mg/litre and 30 mg/litre respectively of dichlorophen. An aqueous solution of the product containing 200 mg/litre dichlorophen was rapidly bactericidal toE. carotovora var.atroseptica but a solution containing 2.3 g/litre a.i. failed to kill spores of a pectolytic clostridium. Immersion of tubers in a solution containing 200 mg/litre dichlorophen gave a concentration of about 53 mg/kg in the peel. Formulations applied as dips or sprays at concentrations of up to 2.3 g/litre dichlorophen failed to reduce the incidence of soft rot in tubers stored under <1% O₂ in N₂ at 100% relative humidity and 20 C for up to 11 days. BothE. carotovora and pectolytic clostridia were isolated from rots occurring after treatment of tubers with 2 g litre dichlorophen. Solutions of sodium hypochlorite (0.6–2 g litre free chlorine, pH 9.4–9.7) reduced the incidence of soft rot in unwounded tubers stored in the above conditions.

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Zusammenfassung Das Ausl?sen der bakteriellen Nassf?ule in Kartoffeln wird weitgehend durch die Umweltbedingungen, besonders durch das Vorhandensein eines Wasserfilms und die nachfolgende Ersch?pfung des Sauerstoffes in den Knollen, bestimmt. Um den Einfluss antibakterieller Pr?parate auf die Nassf?ule an Kartoffeln in einem Labortest zu bewerten, k?nnen Knollen in einer Atmosph?re von <1% O₂ in N₂, bei 100% rel. Feuchtigkeit und 20 C zum Faulen gebracht werden. Dichlorophen wurde unter dem Pesticides Safety Precautions Scheme in Grossbritannien als Spray oder Bad mit einer Konzentration von nicht mehr als 2 g/l für die Anwendung an Kartoffeln nach der Ernte freigegeben. Der Einfluss einer Handelsformel. die 100 g/l Dichlorophen enth?lt (Formulierung 1), auf St?mme vonErwinia carotovora und auf pektinolytische Clostridien wurde, untersucht. Der Einfluss von 4 Formulierungen (1–4) von Dichlorophen auf die bakterielle Nassf?ule von Kartoffeln wurde mit jenem von Natriumhypochlorit-L?sungen verglichen. Die kleinsten hemmenden Konzentrationen der Formulierung 1 gegen 10 St?mme vonE. carotovora und 6 St?mme von pektinolytischemClostridium spp. waren ?quivalent mit 25 bzw. 3 mg/l Dichlorophen. Eine L?sung dieses Produktes mit 0.2 g/l Dichlorophen war bei 10⁸ ml¹ E. carotovora var.atroseptica (E. atroseptica) in 30 Sekunden t?dlich. aber eine L?sung mit 2.3 g/l Dichlorophen konnte die Sporen eines pektinolytischen Clostridiums in 30 Minuten nicht t?ten. Eintauchen von Knollen der Sorte Désirée in eine 0.2 g/l Dichlorophen enthaltende L?sung ergab eine Konzentration in der Schale von ungel?hr 53 mg/kg. Formulierung 1 mit 0.2–2.3 g/l Dichlorophen, als Bad (Dauer 2–30 Minuten) angewendet, brachte keine nachfolgende Abnahme der Nassf?ule bei unverletzten oder verletzten Knollen mit oder ohne vorherige Inokulation mitE. atroseptica (Tabellen 1 und 2). Drei weitere Formulierungen, bei denen unverletzte Knollen w?hrend 2 Minuten in ein Bad mit bis zu 2 g/l Dichlorophen (Formulierungen 2 und 3) oder bis zu 4 g/l Duchlorophen (Formulierung 4) eingetaucht wurden, ergaben keine Verringerung des Umfangs an Nassf?ule. SowohlE. carotovora als auch pektinolytisches Clostridium wurden aus F?ulnisstellen in Knollen isoliert, die mit einer 2.3 g/l Dichlorophen enthaltenden L?sung behandelt waren. Eintauchen von Knollen in L?sungen von Natriumhypochlorit (0.6 g/l aktives Chlor, pH 9.4-2 g/l aktives Chlor, pH 9.7) senkte das Ausmass an Nassf?ule, die in den Lentizellen ihren Anfang nahm. Eine vollst?ndige Bek?mpfung wurde aber nicht erreicht (Tabelle 3). Anwendung der Formulierungen 1 und 4 als Spray mit 2 g/l Dichlorophen zu Kartoffeln, die über einen Walztisch rollten, zeigten keinerlei Abnahme der Nassf?ule, wenn die Kartoffeln nachher unter den Testbedingungen im Labor bebrütet wurden (Tabelle 4).

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Résumé Le développement des pourritures molles sur pomme de terre est largement influencé par des conditions d'environnement, plus particuliérement par la présence d'un film d'eau, et par voie de conséquence, par l'absence d'oxygéne autour des tubercules. En fonction de cela, et afin d'évaluer l'effet de composés bactéricides sur la pourriture molle de la pomme de terre par un test au laboratoire, les tubercules peuvent être mis à incuber dans une atmosphère contenant moins de 1% d'O₂ dans l'azote, à 100% d'humidité relative à 20°C de manière à induire les pourritures. Le dichlorophen a été utilisé selon les consignes de sécurité relatives à l'emploi des pesticides après récolte sur pomme de terre, par pulvérisation ou trempage à une concentration ne dépassant pas 2 g/l; l'effet d'une formulation commerciale contenant 100 g/l de dichlorophen (Formulation 1) a été étudié sur des souchesd Erwinia carotovora et sur desClostridium pectinolytiques. l'effet de 4 formulations (1–4) de dichlorophen sur pourriture molle des pommes de terre a été comparé à celui obtenu avec 4 solutions d'hypochlorite de sodium. Pour la formation 1, les concentrations minimales qui se sont révélées inhibitrices à l'égard de 10 souches d'E. carotovora et 6 souches deClostridium spp. pectinolytiques étaient équivalentes respectivement à 25 et 3 mg/l de dichlorophen. Une solution de ce produit, comprenant 0,2 g/l de dichlorophen, s'est révélée létale à 10⁸ ml¹, vis-à-vis d'E. carotovora var.atroseptica (E. atroseptica) en 30 secondes, tandis qu'une solution contenant 2.3 g/l de dichlorophen n'a pu détruire les spores de clostridium pectinolytiques en 30 minutes. Le trempage des tubercules de la variété Désirée dans une solution contenant 0,2 g/l de dichlorophen a donné une concentration dans les pelures de pomme de terre de l'ordre de 53 mg/kg: la formulation 1 appliquée en trempage et contenant 0,2–2,3 g/l de dichlorophen pendant 2–3 minutes ne permet pas d'obtenir une diminution des pourritures molles pour les tubercules non blessés ou blessés, avec ou sans inoculation préalable parE. atroseptica (tableaux 1 et 2). Trois autres formulations contenant jusqu' à 2 g/l de dichlorophen (formulations 2 et 3) ou jusqu' à 4 g/l de dichlorophen (formulation 4) et utilisées en trempage pendant 2 minutes pour des tubercules non blessés ne peuvent diminuer la quantité de pourritures bactériennes. E. carotovora et les clostridium pectinolytiques ont été isolées à partir des pourritures provenant des tubercules ayant été traités avec une solution à 2,3 g/l de dichlorophen. L'immersion de tubercules dans des solutions d'hypochlorite de sodium (0.6 g/l de chlore, pH 9,4–2 g/l de chlore, pH 9.7) a permis de diminuer la quantité de pourriture molle lenticellaire, mais n'a pas permis d'obtenir un contr?le total (tableua 3). L'application par pulvérisation des formulations 1 et 4 contenant 2 g/l de dichlorophen sur les pommes de terre passant sur une table de visite à rouleaux n'a permis aucune diminution de pourriture aprés incubation des pommes de terre dans les conditions de test au laboratoire (tableau 4).

     

Repeatability of flow cytometric and classical measurement of phagocytosis and respiratory burst in bovine polymorphonuclear leukocytes

Five methods for measurement of phagocytosis and respiratory burst activity of bovine blood polymorphonuclear leukocytes (PMNs) were evaluated. Eight cows were repeatedly sampled over a two week period and parallel samples tested in all five assays to assess the repeatability and stability of the methods. In the flow cytometric phagocytosis assay, ingestion of fluorescein labeled bacteria was measured, and in the flow cytometric assay for respiratory burst, oxidation of a dye by reactive oxygen species was recorded. In the classical assays, bactericidal effect on opsonized, live bacteria was quantified by the conversion of an indicator substance, superoxide anion production was assayed by the reduction of cytochrome c, whereas myeloperoxidase activity was determined with a radioactive iodination assay. The results showed that the Phagotest, Bursttest, cytochrome c and iodination assays gave repeatable results when samples were run in the same setup on the same day. Although day-to-day variability was significant in all assays, the described methods comprise a panel of useful tests for the evaluation of phagocytosis and respiratory burst activity in bovine PMNs. The flow cytometric methods represent a convenient alternative to the classical methods for measurement of phagocytosis and respiratory burst in bovine blood PMNs.     

Effect of marker‐data editing on the accuracy of genomic prediction

Genomic selection is a method to predict breeding values using genome‐wide single‐nucleotide polymorphism (SNP) markers. High‐quality marker data are necessary for genomic selection. The aim of this study was to investigate the effect of marker‐editing criteria on the accuracy of genomic predictions in the Nordic Holstein and Jersey populations. Data included 4429 Holstein and 1071 Jersey bulls. In total, 48 222 SNP for Holstein and 44 305 SNP for Jersey were polymorphic. The SNP data were edited based on (i) minor allele frequencies (MAF) with thresholds of no limit, 0.001, 0.01, 0.02, 0.05 and 0.10, (ii) deviations from Hardy–Weinberg proportions (HWP) with thresholds of no limit, chi‐squared p‐values of 0.001, 0.02, 0.05 and 0.10, and (iii) GenCall (GC) scores with thresholds of 0.15, 0.55, 0.60, 0.65 and 0.70. The marker data sets edited with different criteria were used for genomic prediction of protein yield, fertility and mastitis using a Bayesian variable selection and a GBLUP model. De‐regressed EBV were used as response variables. The result showed little difference between prediction accuracies based on marker data sets edited with MAF and deviation from HWP. However, accuracy decreased with more stringent thresholds of GC score. According to the results of this study, it would be appropriate to edit data with restriction of MAF being between 0.01 and 0.02, a p‐value of deviation from HWP being 0.05, and keeping all individual SNP genotypes having a GC score over 0.15.