Identification of bluetongue virus serotype 2 (Corsican strain) by reverse-transcriptase PCR reaction analysis of segment 2 of the genome

In October 2000, bluetongue virus was detected on the French island of Corsica. The disease was also reported in Sardinia, Calabria, Sicily and on the Spanish islands of Majorca and Minorca. This paper describes the use of molecular techniques for a rapid identification and serotype determination of serotype 2 of the virus. The nucleotide sequences of segments 2 and 7 of the genome of the Corsican strain were determined and its phylogenetic relationships are described.     

Antigen-specific IgG(T) responses in natural and experimental cyathostominae infection in horses

Equine clinical larval cyathostominosis is caused by simultaneous mass emergence of previously inhibited larvae from the mucosa of the colon. Clinical signs include diarrhoea, colic, weight loss and malaise, and in up to 50% of cases, the disease results in death. Cyathostominae spend a large part of their life cycle as larval stages in the intestinal mucosa. Definitive diagnosis is difficult due to the lack of diagnostic methods for pre-patent infection. In the present study, the enzyme-linked immunosorbent assay (ELISA) was used to investigate isotype responses to larval cyathostominae somatic antigen. Measurement of anti-larval IgG(T) responses appeared to have the most immunodiagnostic potential. An increase in IgG(T) response was detected to crude larval antigen by 5 weeks post-infection (PI) in individual infected ponies. Subsequently, IgG(T) responses to larval and adult somatic extracts were examined by Western blotting using sera from experimentally-infected horses and helminth-naive animals (n=6). Two antigen complexes, designated A and B, in larval somatic antigen were recognised specifically by the infected animals by 7 weeks PI. Sera taken from 23 endemically-infected animals, whose cyathostominae burdens had been enumerated, were also used to identify putative diagnostic antigens. Eighteen horses had positive mucosal worm burdens (range 723-3,595,725) and all but two of these animals had serum IgG(T) antibody specific to either complex. Moreover, IgG(T) responses specific to antigen complexes A and B were absent in all five parasite negative horses that were tested. Serum IgG(T) responses to either of the two complexes were identified in five clinical cases tested. IgG(T) responses to adult antigen somatic extracts were more heterogeneous, with no clear pattern between experimentally-infected ponies and helminth-free controls. The results indicate that increases in serum IgG(T) to mucosal larvae occur in the pre-patent period and that two antigenic complexes within somatic preparations of these stages have immunodiagnostic potential.     

Effects of dietary ingredients on manure characteristics and odorous emissions from swine

Two feeding studies were conducted to examine the impact of dietary inclusion of specific feed ingredients on manure characteristics and manure odor. In one study, 72 finishing pigs were used to evaluate the effects of distillers dried grains with solubles (DDGS) on pig performance, manure characteristics, and odorous emissions. Three diets containing 0, 5, and 10% DDGS were fed during six 4-wk feeding periods. Week 1 served as a dietary adjustment period. Animals were housed in two feeding rooms (six pigs/room) with one treatment/room. A new group of animals (average initial BW = 85.8 kg) was used for each feeding period. Diets were replicated four times. Rooms were equipped with individual shallow manure storage pits that were cleaned once weekly (d 7). On d 4 and 7 of each week, manure pit samples, for chemical analyses, and air samples, for olfactometry analysis, were collected from each room. Odor dilution threshold was greater on d 7 than on d 4 of manure storage across all treatments (P < 0.01). No treatment differences in manure composition were noted. In the second study, weaned pigs (approximately 5 wk old) were fed isonitrogenous diets containing 0, 1.5, or 3% bloodmeal. Pigs were housed by diet (three pigs/diet) in one of four individual feeding rooms. A new group of pigs was used for each of the two, 4-wk feeding periods. During period 1, the 3% bloodmeal diet was fed in two of the four rooms; the 0% bloodmeal diet was fed in two rooms during period 2. Manure samples, for chemical analyses, and air samples, for olfactometry analysis, were collected 2 d per week (d 4 and d 6) from each room during wk 2 through 4. No significant treatment differences were observed for odor dilution threshold (P = 0.30). Longer manure storage time, 6 d vs 4 d, resulted in a larger odor dilution ratio (P < 0.01). Manure composition was unaltered by storage time. Results suggest that odor intensifies during storage.     

Effects of Ascophyllum nodosum extract on growth performance and immune function of young pigs challenged with Salmonella typhimurium

Ninety-five pigs (initially 7.1 kg and 24 d of age) were used in a 28-d experiment to determine the effects of Ascophyllum nodosum seaweed extract (ANOD) on young pig growth performance and immune function in response to enteric disease challenge with Salmonella typhimurium (ST). Experimental treatments were arranged in a 2 x 4 factorial with main effects of disease challenge (control vs ST-challenge) and dietary addition of ANOD (0, 0.5, 1.0, and 2.0% of diet). Pigs were fed ANOD diets for 14 d and then challenged orally with ST or sterile media. There were no main effects of ANOD on growth performance end points, although there were significant quadratic effects of ANOD on ADG (P < 0.04) and final weight (P < 0.003), both being greatest at 1.0% ANOD. There was a positive linear effect of ANOD inclusion on ADFI (P < 0.07) and a negative linear effect on the gain-to-feed ratio (G/F) (P < 0.05). ST-challenge reduced ADG (P < 0.05), ADFI (P < 0.05), and G/F (P < 0.05) in the first week following challenge. Daily estimates revealed reductions in feed intake in ST-infected pigs on d 2 to 4 following infection (P < 0.05). Rectal temperature was increased maximally 2 d following ST-infection (P < 0.05). A disease challenge x time interaction (P < 0.001) was observed for serum haptoglobin and alpha1-acid glycoprotein. Serum immunoglobulin M (IgM) was not influenced by disease challenge, but IgM declined (P < 0.001) in all pigs over time. Serum immunoglobulin G (IgG) also was not influenced by disease challenge, but IgG tended (P < 0.08) to increase over time. In vitro culture of porcine alveolar macrophages with 10 mg/mL ANOD elevated (P < 0.05) prostaglandin E2 (PGE2) production over that of controls at 3 and 24 h of culture. There was no interleukin-10 response by porcine splenocytes cultured in vitro with 0.005, 0.05, 0.5, or 5 mg/mL ANOD. We conclude that this model of enteric disease elicits an acute phase response that is accompanied by increased rectal temperature and diminished feed intake. Furthermore, our results indicate some beneficial effects of dietary ANOD on growth performance and no influence of dietary ANOD on immune response in the presence or absence of ST-challenge. However, high ANOD concentrations are capable of activating porcine alveolar macrophages in vitro to secrete PGE2.     

An avian model of limb deviation induced by periosteal surgery

A model of limb deviation induced by hemi-circumferential periosteal stripping of the distal tibiotarsus of domestic chicks is described. This model has been developed to study the effects of periosteal stripping on the cellular, mechanical, vascular, and biochemical status of the immature bone and growth plate. It is hoped that such studies may further elucidate the mechanisms involved in altered bone growth following periosteal stripping techniques which are used in human and equine orthopaedics for the management of leg length discrepancies and angular limb deformities respectively (Auer and Martens 1980, Warrell and Baker 1987). Hemi-circumferential periosteal stripping of the left distal tibiotarsus of 28-day-old chicks resulted in significant change in metaphyseal-diaphyseal angle with time, compared to both the controls and the untreated right legs (P<0.0001). This model of limb deviation developed rapidly and consistently, and the procedures were well tolerated by the birds over the short survival time (maximum 28 days).     

Foetal Protection against Bovine Virus Diarrhoea Virus after Two‐step Vaccination

In order to assess the efficacy of a two‐step vaccination protocol with respect to foetal protection against transplacental infections with bovine virus diarrhoea virus (BVDV) with special attention to BVDV‐2 seronegative heifers were vaccinated with an inactivated BVDV‐1 vaccine and boostered with a modified live BVDV‐1 vaccine after 4 weeks. A second group was left unvaccinated as control. Between days 30 and 120 of pregnancy the heifers of both groups were intranasally challenged with a mixture of BVDV‐1 and ‐2. All heifers of the vaccinated group gave birth to nine clinically healthy, seronegative (precolostral) and BVDV‐free calves. In contrast in the control group four BVDV viraemic underdeveloped calves were born. Additionally, one calf was stillborn and another viraemic calf was not viable and died 2 days after birth. All six calves of the control group were viraemic with BVDV‐2. This study demonstrated for the first time that two‐step vaccination of breeding cattle with a modified live BVDV vaccine 4 weeks after application of an inactivated BVDV vaccine was capable of providing a foetal protection against transplacental infection with BVDV‐2.     

Water transport in the kidney and nephrogenic diabetes insipidus

Nephrogenic diabetes insipidus is caused by an inability of the kidney to concentrate urine despite adequate concentration of vasopressin in blood and is characterized by polyuria, polydipsia, and hyposthenuria in the presence of plasma hyperosmolality. Nephrogenic diabetes insipidus is the result of defects in water homeostasis in the kidney. Nephrogenic diabetes insipidus occurs when the kidneys cannot or do not respond to vasopressin. There are 2 categories of nephrogenic diabetes insipidus. Congenital nephrogenic diabetes insipidus is a rare, inherited, irreversible cause of polyuria and polydipsia in humans that is even rarer in animals. Acquired nephrogenic diabetes insipidus is more common and is often secondary to illness or medication that interferes with the action of vasopressin in the renal tubules. Unlike congenital nephrogenic diabetes insipidus, acquired or secondary nephrogenic diabetes insipidus is often reversible with correction of the associated or causative problem.     

Genetic parameter estimates for growth traits in Horro sheep

Variance components and genetic parameters were estimated for growth traits: birth weight (BWT), weaning weight (WWT), 6‐month weight (6MWT) and yearling weight (YWT) in indigenous Ethiopian Horro sheep using the average information REML (AIREML). Four different models: sire model (model 1), direct animal model (model 2), direct and maternal animal model (model 3) and direct–maternal animal model including the covariance between direct and maternal effects (model 4) were used. Bivariate analysis by model 2 was also used to estimate genetic correlation between traits. Estimates of direct heritability obtained from models 1–4, respectively, were for BWT 0.25, 0.27, 0.18 and 0.32; for WWT, 0.16, 0.26, 0.1 and 0.14; for 6MWT 0.18, 0.26, 0.16 and 0.16; and for YWT 0.30, 0.28, 0.23, and 0.31. Maternal heritability estimates of 0.12 and 0.23 for BWT; 0.19 and 0.24 for WWT; 0.09 and 0.09 for 6MWT and 0.08 and 0.14 for YWT were obtained from models 3 and 4, respectively. The correlations between direct and maternal additive genetic effects for BWT, WWT, 6MWT and YWT were –0.64, –0.42, 0.002 and –0.46, respectively. On the other hand, the genetic correlations between BWT and the rest of growth traits (WWT, 6MWT and YWT, respectively) were 0.45, 0.33 and 0.31, whereas correlations between WWT and 6MWT, WWT and YWT and 6MWT and YWT were 0.98, 0.84 and 0.87, respectively. The medium to high direct and maternal heritability estimates obtained for BWT and YWT indicate that in Horro sheep faster genetic improvement through selection is possible for these traits and it should consider both (direct and maternal) h² estimates. However, since the direct‐maternal genetic covariances were found to be negative, caution should be made in making selection decisions. The high genetic correlation among early growth traits imply that genetic improvement in any one of the traits could be made through indirect selection for correlated traits.     

Comparison of artificial light sources and lighting programmes for laying hens on long ahemeral light cycles

Three lighting treatments were given to laying hens, for which the bright and dim light of 28-h ahemeral light cycles was provided by incandescent (tungsten filament) lamps only or by combinations of tubular fluorescent or compact gas-discharge lamps with incandescent lamps. There were no differences in entrainment (the proportion of eggs laid in 4, 6 or 8 h modal periods) between the three bright:dim treatments. A fourth ahemeral lighting treatment in which the dim lights were extinguished except during a designated work period (09.00 h to 12.00 h daily) was termed bright:dim:dark. Hens given the bright:dim:dark treatment showed an increased entrainment compared with the three bright:dim light treatments. There were no differences (P greater than 0.05) in egg numbers or mean egg weight between all 4 lighting treatments. Birds given the bright:dim:dark treatment tended to have a lower (P greater than 0.05) food intake compared to the three bright:dim treatments.