Genetic study of fertility traits and production in different parities in Italian Friesian cattle

ZUSAMMENFASSUNG: Genetische Analyse von Fruchtbarkeits- und Produktionsmerkmalen bei italienischen Schwarzbunten in verschiedenen Laktationen Produktions- und Reproduktionsdaten von italienischen Schwarzbunten sind für die Analyse von Wechselbeziehungen zwischen den Merkmalen Zwischentragzeit, Rastzeit, Tr?chtigkeitsrate bei Erstbesamung, Anzahl von Besamungen je Tr?chtigkeit einerseits und der 305 Tage Milchleistung andererseits verwendet worden. Die Milchleistung der Kühe wurde für Laktationsnummer, Kalbealter und Zwischentragezeit korrigiert. Die Analyse wurde für die ersten drei Abkalbungen getrennt durchgeführt. Die Sch?tzwerte für die Heritabilit?t liegen für die Fruchtbarkeitsmerkmale zwischen .01 und .03 und für die Milchleistungsmerkmale zwischen .16 und .22. Für die Wiederholbarkeiten wurden Werte zwischen .02 und .08 (Fruchtbarkeit) bzw. .49 und .59 (Milchleistung) gesch?tzt. Die genetische Korrelation zwischen Milchmenge und Zwischentragezeit, zwischen Milchmenge und Rastzeit sowie zwischen Tr?chtigkeitsrate bei Erstbesamung und Anzahl Besamungen je Tr?chtigkeit betr?gt .70, .92 und -.98, resp. Zwischen Fruchtbarkeits- und Milchleistungsmerkmalen wurden generell negative Korrelationen gesch?tzt, was als Antagonismus zwischen Fruchtbarkeit und Milchleistung interpretiert werden mu?. Dies bedeutet, da? bei ausschlie?licher Selektion nach Milchleistung negative Auswirkungen bezüglich der Fruchtbarkeit der Kühe zu erwarten sind. Als m?gliche Selektionsmerkmale für die Zuchtwertsch?tzung auf Fruchtbarkeit werden Tr?chtigkeitsrate bei Erstbesamung und Rastzeit (oder alternativ Anzahl Besamungen je Tr?chtigkeit) vorgeschlagen. SUMMARY: A data set of production records with breeding information was used to analyse the relationship between open period, days to first breeding, conception rate at first service, number of services per conception and 305 day milk yield adjusted for age/month of calving and open period in the Italian Friesian Cattle Breed. Separate analyses were performed for the first three parities. Heritability estimates for reproductive traits varied from .01 to .03 and for productive traits from .16 to .22 depending on parities. Repeatabilities for fertility traits were .02 to .08 while for milk yield they were between .49 and .59. Open period and days to first service were found to be highly correlated (genetic correlation: +.70 / +.92) as were conception rate at first service and number of services per conception (-.98). An antagonistic genetic relationship was found between all reproductive traits considered and production. The magnitude of the antagonistic genetic association between production and fertility indicate that genetic deterioration of fertility is to be expected if selection pressure continues to be applied to milk production only. For multiple trait selection, the reproductive measures which complement each other are days to first service and first service conception rate (or number of services per conception).     

Experimental infection of calves with two strains of bovine virus diarrhoea virus: certain immunological reactions

Certain immunological responses of 4-6 month old calves experimentally inoculated with either cytopathic or non-cytopathic bovine virus diarrhoea virus (BVDV) were compared with those of uninfected control calves. The tests used to demonstrate the immunological responses were the transformation of lymphocytes by PHA mitogen, the percentage of lymphocytes with surface immunoglobulin, and the antibody titres induced by an intravenous inoculation of killed Brucella abortus. There were no significant differences between the two groups of calves and therefore, the mild experimental disease produced by BVDV did not appear to affect adversely the immunological response.     

Helping students learn veterinary physiology through the use of concept maps

Concept maps have become a ubiquitous tool in education in the last 20 years and are used extensively to teach scientific concepts. A concept map is a tool learners can use to organize information about a topic in terms of key concepts and the relationships among them. As a graphical representation, the map provides an overall picture of a particular concept or topic. This article describes how we have used concept maps to teach physiology to veterinary medical and veterinary technician students enrolled in our on-campus and distance-learning programs.     

Demonstrating freedom from disease using multiple complex data sources 2: case study--classical swine fever in Denmark

A method for quantitative evaluation of surveillance for disease freedom has been presented in the accompanying paper (Martin et al., 2007). This paper presents an application of the methods, using as an example surveillance for classical swine fever (CSF) in Denmark in 2005. A scenario tree model is presented for the abattoir-based serology component of the Danish CSF surveillance system, in which blood samples are collected in an ad hoc abattoir sampling process, from adult pigs originating in breeding herds in Denmark. The model incorporates effects of targeting (differential risk of seropositivity) associated with age and location (county), and disease clustering within herds. A surveillance time period of one month was used in the analysis. Records for the year 2005 were analysed, representing 25,332 samples from 3528 herds; all were negative for CSF-specific antibodies. Design prevalences of 0.1-1% of herds and 5% of animals within an infected herd were used. The estimated mean surveillance system component (SSC) sensitivities (probability that the SSC would give a positive outcome given the animals processed and that the country is infected at the design prevalences) per month were 0.18, 0.63 and 0.86, for among-herd design prevalences of 0.001, 0.005 and 0.01. The probabilities that the population was free from CSF at each of these design prevalences, after a year of accumulated negative surveillance data, were 0.91, 1.00 and 1.00. Targeting adults and herds from South Jutland was estimated to give approximately 1.9, 1.6 and 1.4 times the surveillance sensitivity of a proportionally representative sampling program for these three among-herd design prevalences.     

New insights into the structural characteristics of the arabinogalactan-protein (AGP) fraction of gum arabic

The structural characteristics of the gum exudate of Acacia senegal (gum arabic) have been investigated by monitoring the composition and physicochemical properties before and after treatment with proteolytic enzyme and various alkaline systems. Molecular mass ( M w) and radius of gyration ( R g) measurements were performed using gel permeation chromatography (GPC) coupled to refractive index, UV absorbance, and multiangle light scattering detectors and indicated that the macromolecules present have a compact structure. It was found that treatment with proteolytic enzyme caused the arabinogalactan-protein component (AGP) with average molecular mass approximately 2 x 10 (6) Da to degrade, yielding material of molecular mass approximately 4 x 10 (5) Da, whereas the bulk of the material corresponding to the protein-deficient arabinogalactan component (AG) with molecular mass 4 x 10 (5) remained unaffected. Barium hydroxide was found to hydrolyze the polysaccharide component (AG) itself in addition to the proteinaceous component as demonstrated in control experiments using dextran. However, sodium borohydride/sodium hydroxide treatments were unable to hydrolyze dextran and were assumed to hydrolyze only the proteinaceous component of gum arabic. The AGP component was completely degraded, yielding material of molecular mass approximately 4.5 x 10 (4) Da. It has been concluded, therefore, that the enzyme did not fully hydrolyze all of the protein present and that the AGP component of gum arabic consists of carbohydrate blocks of approximately 4.5 x 10 (4) Da linked to a polypeptide chain consistent with the wattle blossom structure. Because the AGP was degraded to differing extents using a mild and more severe sodium borohydride/sodium hydroxide treatment, it was concluded that the polysaccharide moieties were linked through both O-serine and O-hydroxyproline residues. The gum arabic sample was deglycosylated by treatment with anhydrous hydrogen fluoride and revealed the presence of two putative core proteins of approximately 3 x 10 (4) and approximately 5 x 10 (3) Da, respectively, which correspond to proteins of approximately 250 and 45 amino acids in length. A new model for the structure of the AGP component has been proposed.     

Quantification of the group B soyasaponins by high-performance liquid chromatography

High-performance liquid chromatographic methods were developed for the isolation and quantitative determination of the group B soyasaponins, including 2,3-dihydro-2,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP)-conjugated soyasaponins alphag, betag, and betaa, and their non-DDMP counterparts, soyasaponins V, I, and II, respectively, with formononetin used as the internal standard. The limits of quantification for soy products were 0.11-4.86 micromol/g. The within-day and between-days assay coefficients of variation were <9.8 and < 14.3%, respectively. The group B soyasaponin concentrations in 46 soybean varieties ranged from 2.50 to 5.85 micromol/g. Soy ingredients (soybean flour, toasted soy hypocotyls, soy protein isolates, textured vegetable protein, soy protein concentrates, and Novasoy) and soy foods (commercial soy milk, tofu, and tempeh) contained the group B soyasaponins from 0.20 to 114.02 micromol/g. There was no apparent correlation between isoflavone and soyasaponin concentrations in the soy products examined.     

Interaction between protein, phytate, and microbial phytase. In vitro studies

The interaction between protein and phytate was investigated in vitro using proteins extracted from five common feedstuffs and from casein. The appearance of naturally present soluble protein-phytate complexes in the feedstuffs, the formation of complexes at different pHs, and the degradation of these complexes by pepsin and/or phytase were studied. Complexes of soluble proteins and phytate in the extracts appeared in small amounts only, with the possible exception of rice pollards. Most proteins dissolved almost completely at pH 2, but not after addition of phytate. Phytase prevented precipitation of protein with phytate. Pepsin could release protein from a precipitate, but the rate of release was increased by phytase. Protein was released faster from a protein-phytate complex when phytase was added, but phytase did not hydrolyze protein. Protein was released from the complex and degraded when both pepsin and phytase were added. It appears that protein-phytate complexes are mainly formed at low pH, as occurs in the stomach of animals. Phytase prevented the formation of the complexes and aided in dissolving them at a faster rate. This might positively affect protein digestibility in animals.