The effect of stress, applied immediately before stunning, on pork quality.

The effect on meat quality characteristics of stress, applied during a short period just before stunning, was studied on slaughterpigs (113 boars, 85 gilts). Sexes were kept separately and only pigs that had been stunned correctly were included. Aggressive behaviour during lairage occurred more frequently in boars (about twice) than in gilts.

An internal duplication in the 5' noncoding region of strain H: a bovine viral diarrhoea virus (BVDV) isolated from pigs.

A pig pestivirus isolate, strain H, was characterized by using reverse transcription-PCR (RT-PCR) and direct sequencing of the amplicons. A duplication of 74 nucleotides was found at the 5' terminus of the 5' noncoding (NC) region, which was also found in RNA isolates from tonsils from two other pigs from the same farm. When the duplication was omitted, the 5' NC region showed 97.

Spontaneous BHV1 recombinants in which the gI/gE/US9 region is replaced by a duplication/inversion of the US1.5/US2 region.

In a bovine herpesvirus 1 (BHV1) vaccine strain, a spontaneous BHV1 mutant (Za) was found that arose from a recombination between two isomeric forms of the BHV1 genome. In this Za mutant one end of the U(S) region, containing part of the US1.5 gene, was found duplicated in an inverted orientation at the other end of the U(S) region.

Characterisation of a polymorphic Tc1-like transposable element of the parasitic nematode Haemonchus contortus.

Hctc1, a member of the Tc1-family of transposable elements was isolated from the parasitic nematode Haemonchus contortus. Hctc1 is 1590 bp long, is flanked by 55 bp inverted repeats and carries a single open reading frame of a 340 amino acid transposase-like protein. Hctc1 is similar to Tc1 of Caenorhabditis elegans and elements Tcb1 and Tcb2 of Caenorhabditis briggsae in the inverted terminal repeats, the open reading frame, as well as the target insertion sequence.

Transmission of classical swine fever virus by artificial insemination.

Classical swine fever (CSF) virus was introduced into an artificial insemination centre during the CSF epizootic of 1997-1998 in the Netherlands. The risk of further spread of CSF virus via contaminated semen was recognised, but could not be assessed because scientific data on this issue were not available. An animal experiment was performed to determine whether CSF virus could be transmitted via artificial insemination with contaminated semen.

High carbon dioxide tension (PCO2) and the incidence of cardiac arrhythmias in rapidly growing broiler chickens.

The purpose of this investigation was to determine whether two-week-old rapidly growing broiler chickens with high metabolic activity have an increased risk of the development of heart failure three to five weeks later. The incidence of cardiac arrhythmias was assessed in broiler chickens with either a relatively high carbon dioxide tension (PCO2) or a low PCO2 in their venous blood. Their electrocardiograms (ECGS) were measured when the birds were between five and seven weeks old by means of a biotransplant which allowed them to move freely.

Effect of the ratio between essential and nonessential amino acids in the diet on utilization of nitrogen and amino acids by growing pigs.

In 36 growing pigs (30 to 60 kg), N balance and amino acid (AA) composition of weight gain were measured to evaluate the interactive effect of the ratio between N from essential amino acids (EAA(N)) to nonessential amino acids (NEAA(N)) and total N level (T(N)) in the diet on N retention and utilization of N, EAA(N), NEAA(N), and AA. Nine diets composed from ordinary feedstuffs and supplemented with crystalline AA were used (three EAA(N):NEAA(N) ratios of 38:62, 50:50, and 62:38 at three T(N) levels of 18.8, 22.

The effect of shot biopsy on behavior, salivary cortisol, and heart rate in slaughter pigs.

This paper describes behavioral and physiological responses of pigs to shot biopsy, an experimental method used to study muscle tissue processes or to predict meat quality. One biopsy sample from the longissimus muscle was obtained from 23-wk-old gilts (n = 10) using a cannula connected to a captive bolt. Ten other gilts were used as a control and received a sham shot.

Some neural and behavioural aspects of electrical and mechanical stunning in ostriches.

Different electrical and mechanical stunning procedures were studied in ostriches to determine the effectiveness of the method. Fifty-eight South-African Black ostriches were equipped with EEG electrodes and stunned with three different electrical head-only methods and with a new captive needle pistol, using air pressure. The first stunning procedure consists of two trials.

Sensitivity testing of veterinary pathogens with a semi-automatic image analysis system compared with tablet diffusion and agar dilution tests.

Recently a commercial computer-controlled image analysis system (IAS) was introduced to measure automatically the diameters of inhibition zones in the agar diffusion test. However, there is little information on the precision of this method. In the present study clinical isolates of Salmonella spp.

Prediction of daily milk yields from a limited number of test days using test day models.

A data set of weekly milk yield records was used to compare different test day models for their ability to interpolate and extrapolate missing milk yields. The criteria to compare the models were 1) the (co)variance structure modeled compared with the observed (co)variance structure in the data and 2) mean square error of predictions of missing observations (MSEP), which compared the predicted value of a missing record to the known value of the record. The test day models used were LEG(m), which are Legendre polynomials with an order of fit of m, and EXP, which is an exponential lactation function.

Genome analysis of Marek's disease virus strain CVI-988: effect of cell culture passage on the inverted repeat regions.

The genomes of different derivatives of Marek's disease virus (MDV) strain CVI-988, a low oncogenic isolate of a serotype 1 MDV, were analyzed by restriction enzyme analyses to detect whether alterations occurred after passages in cell culture. DNA molecules of strain 988 isolated directly from blood cells contained mainly two copies of the 132-bp repeat sequence previously reported within BamH1-H and -D fragment as previously reported for more virulent MDV strains. Although a minority of virus particles showed repeat amplification was already at the fifth passage level, amplification mainly occurred between passages 17 and 34 in cell culture.

Comparative sequence analysis of classical swine fever virus isolates from the epizootic in The Netherlands in 1997-1998.

Sixteen classical swine fever virus (CSFV) field isolates from outbreaks of classical swine fever from the period between February 1997 and March 1998 in the Netherlands were sequence analysed. Parts of the 5' noncoding region (5'NCR) and the E1/E2 gene were sequenced after RT-PCR. The obtained sequences were compared with isolates of recent outbreaks in Europe and those of former outbreaks in the Netherlands.

Scrapie-associated prion protein in the gastrointestinal tract of sheep with natural scrapie.

The scrapie-associated prion protein (PrPSc), which is closely associated with scrapie infectivity, accumulates in the brain and lymphoid tissues of sheep with natural scrapie. The most probable portal of entry of the scrapie agent in sheep is the alimentary tract; little attention, however, has been paid to the gastro-intestinal tract in scrapie research. In this study, we examined the presence and distribution of PrPSc within the gastro-intestinal tract of sheep with natural scrapie and scrapie-negative sheep.

Organic acids for performance enhancement in pig diets.

Organic acids and their salts appear to be potential alternatives to prophylactic in-feed antibiotics and growth promoters in order to improve the performance of weaned piglets, fattening pigs and reproductive sows, although their growth-promoting effects are generally less than that of antibiotics. Based on an analysis of published data, the growth-promoting effect of formates, fumarates and citrates did not differ in weaned piglets. In fattening pigs, formates were the most effective followed by fumarates, whereas propionates did not improve growth performance.

Intake and excretion of sodium, potassium, and nitrogen and the effects on urine production by lactating dairy cows.

The present study was designed to describe the relationship between mineral metabolism and urine production by lactating dairy cows. Regression studies were performed to predict urine volume from either observed concentrations of K, Na, and N in urine or observed intakes of K, Na, and N. In addition, empirical equations were derived to assist in the estimation of urinary excretion of K, Na, and N in practical situations.

Different techniques to study rumen fermentation characteristics of maturing grass and grass silage.

Grass samples were harvested during the 1993 growing season after a precut on April 27, 1993 and were stored frozen or left to ensile in 30-L buckets. Effects on chemical composition and fermentation kinetics of the maturation of the grass and of ensiling were investigated. Chemical composition and fermentation kinetics were determined using the gas production technique, in vitro techniques, and the nylon bag technique.

Influence of capacitation and fluids from the male and female genital tract on the zona binding ability of bull spermatozoa.

Before fertilization, inseminated spermatozoa acquire the ability to fertilize an egg, a phenomenon called capacitation. Bovine sperm capacitation is influenced by factors originating from both the male and female genital tract, and results in intracellular and membrane changes of the spermatozoa that facilitate the induction of the acrosome reaction. However, the effects of reproductive tract secretions and capacitation on the binding of spermatozoa to the zona pellucida have not been investigated.

Effect of genetic variants of the heart fatty acid-binding protein gene on intramuscular fat and performance traits in pigs.

In order to find genetic markers to improve the meat quality of pigs by breeding we studied the relationship between variation in the heart fatty acid-binding protein (H-FABP) gene (FABP3) and intramuscular fat (IMF) content. To estimate the effect of H-FABP, pigs from two Duroc populations were selectively mated in such a way that at least two genotypes were present in each litter. In total, data from 983 pigs and pedigree information from three preceding generations were analyzed.

Protection against Fasciola hepatica in the intestine is highly correlated with eosinophil and immunoglobulin G1 responses against newly excysted juveniles.

Rats were infected with Fasciola hepatica and challenged at regular intervals up to 38 weeks using an ex vivo gut loop, a technique developed in our laboratory. The kinetics of the observed immune responses against F. hepatica in gut tissue and serum were investigated and correlated to protection.

The effect of feed withdrawal on broiler blood glucose and nonesterified fatty acid levels, postmortem liver pH values, and carcass yield.

Feed withdrawal should start 5 h before broilers are captured and transported to the processing plant. This practice results in a total feed withdrawal period of about 8 h before slaughter. To check observance of this period at the plant reliably, blood samples were collected at slaughter from broilers.

Effects of repeated jugular puncture on plasma cortisol concentrations in loose-housed dairy cows.

In three experiments, the effects of venipuncture on plasma cortisol concentrations were studied in loose-housed dairy cows. In Exp. 1, two blood samples were collected 18 min apart on three alternate days from 20 dairy cows for studying their adrenocortical response to a single venipuncture.

A single social defeat transiently suppresses the anti-viral immune response in mice.

Most of the studies dealing with effects of stress on anti-viral immunity have been carried out with stressors that are of long duration and that bear little relationship to the nature of the species. In this paper, we investigated the effect of a stressor mimicking real-life situations more closely, being social defeat of male mice, on anti-viral immunity. A single social defeat was applied at 3 or 6 days after inoculation with pseudorabies virus, a herpes virus.

Efficacy and stability of a subunit vaccine based on glycoprotein E2 of classical swine fever virus.

The purpose of this study was to determine the efficacy and stability of an E2 subunit vaccine against classical swine fever virus (CSFV). The vaccine, which contains E2 produced in insect cells by a baculovirus expression vector is a potential marker vaccine, as it allows discrimination between infected and vaccinated pigs. Several vaccination-challenge experiments were performed to determine the dose that protects 95% of the vaccinated pigs (PD95), and to determine the stability and efficacy of the vaccine several months after production.

Recovery of infectious classical swine fever virus (CSFV) from full-length genomic cDNA clones by a swine kidney cell line expressing bacteriophage T7 RNA polymerase.

A new method for the recovery of infectious classical swine fever virus (CSFV) from full-length genomic cDNA clones of the C-strain was developed. Classical reverse genetics is based on transfection of in vitro transcribed RNA to target cells to recover RNA viruses. However, the specific infectivity of such in vitro transcribed RNA in swine kidney cells is usually low.