The effect of lighting conditions on the rhythmicity of growth hormone secretion in Holstein steers

Growth hormone (GH) secretion regularity and the effects of lighting condition and GH‐releasing hormone (GHRH) on GH release were determined in steers. First, steers were kept under 12:12 L : D conditions (light: 06.00–18.00 hours). The animals were then subjected to a 1‐h advancement in lighting on/off conditions (05.00 and 17.00 hours, respectively). Blood was sampled for 24 h at 1‐h interval on the seventh day of each condition. Second, GHRH was injected intravenously (IV) at 12.00 and 00.00 hours under 12:12 L : D and blood was sampled at 15‐min interval for 4‐h (1 h before and 3 h after the injection). Plasma GH concentrations were measured by a radioimmunoassay. Periodicity of GH secretory profile was calculated by power spectrum analysis using the maximum entropy method. Plasma GH concentrations showed a characteristic pattern consisting of four distinct peaks. Mean periodicity of GH secretory profile was 5.7 h, and it was not altered by any change in lighting conditions. IV injection of GHRH increased GH secretion during the day and night. The increase in GH secretory volume after GHRH injection during the night was equal to that during the day. The present results suggest that GH secreted from the anterior pituitary have regularity in steers.     

Clinical and clinico-pathologic characteristics of Shiba dogs with a deficiency of lysosomal acid beta-galactosidase: a canine model of human GM1 gangliosidosis

The present study was conducted to determine the clinical and clinico-pathologic characteristics of Shiba dogs with GM1 gangliosidosis, which is due to an autosomal recessively inherited deficiency of lysosomal acid beta-galactosidase activity. Clinical and clinico-pathological features were investigated in 10 homozygous Shiba dogs with GM1 gangliosidosis. The age at onset was 5 to 6 months and the dogs manifested progressive neurologic signs including loss of balance, intermittent lameness, ataxia, dysmetria and intention tremor of the head. The dogs were unable to stand by 10 months of age due to a progression of ataxia and spasticity in all limbs. Corneal clouding, a visual defect, generalized muscle rigospasticity, emotional disorder and a tendency to be lethargic were observed at 9 to 12 months. The dogs became lethargic from 13 months of age. The survival period seemed to be 14 to 15 months. As a clinico-pathologic feature, lymphocytes with abnormally large vacuoles were observed in peripheral blood (30 to 50% of total lymphocytes) through the lifetime of the dogs. The clinical and clinico-pathologic characteristics of this animal model are useful for not only the development and testing of potential methods of therapy, but also the diagnosis of affected homozygous Shiba dogs in veterinary clinics.     

Comparison of polymerase chain reaction-restriction fragment length polymorphism assay and enzyme assay for diagnosis of G(M1)-gangliosidosis in Shiba dogs.

In the present study, diagnostic methods for canine G(M1)-gangliosidosis were examined by comparing a DNA mutation assay with an enzyme assay. Sixty-two Shiba dogs of a pedigree with G(M1)-gangliosidosis were differentiated into 3 genotypes, i.e., normal, heterozygous, and homozygous affected dogs, using a DNA mutation assay, which consists of polymerase chain reaction amplification and the determination of restriction fragment length polymorphisms. The beta-galactosidase activity in leukocytes, umbilical cords, and plasma was measured using 4-methylumbelliferyl beta-D-galactoside and p-nitrophenyl beta-D-galactoside as artificial substrates and compared among the 3 genotypes. The results showed that it was possible to identify homozygous dogs with the enzyme assay using leukocytes and umbilical cords. When using leukocytes, heterozygous carriers could be differentiated from normal dogs in many cases. However, the use of the DNA mutation assay is essential for a complete determination of heterozygous carriers because of the overlap in the distribution of enzyme activity between these 2 groups. When umbilical cords were used, heterozygous carriers could not be differentiated from normal dogs because of no significant difference in enzyme activity between these 2 groups. The beta-galactosidase activity in plasma was not applicable to the diagnosis and genotyping of G(M1)-gangliosidosis in Shiba dogs.     

Effect of intracerebroventricular injections of prolactin‐releasing peptide on prolactin release and stress‐related responses in steers

Some evidence suggests that there might be a species difference in the effect of intracerebroventricularly administered (ICV) prolactin‐releasing peptide (PrRP) between rodents and sheep. We compared the levels of cortisol (CORT) and prolactin (PRL), rectal temperature (RT) and behavioral responses to ICV bovine PrRP (bPrRP) in steers. ICV bPrRP (0.2, 2 and 20 nmol/200 µL) tended to evoke a dose‐related increase in CORT concentrations and 0.2 nmol of bPrRP induced transient increase in PRL concentrations. A significant time–treatment interaction was observed for the percent change of CORT (P < 0.05) and PRL (P < 0.05) from pre‐injection value. The time–treatment interaction for changes in RT was not significant (P = 0.50). There tended to be a difference among the four treatments in terms of maximum change in RT from the pre‐injection value between 0 and 90 min (P < 0.1). Stress‐related behavioral signs were not observed in the present experiment. These findings indicate that ICV bPrRP increased CORT and PRL levels, suggesting that central PrRP might participate in controlling the hypothalamo‐pituitary‐adrenal axis and PRL release in cattle, unlike sheep. In contrast, central PrRP is unlikely to be involved in controlling the behavior of this species because ICV bPrRP did not induce marked changes in their behavior.     

Seroprevalence of antibody to NcSAG1 antigen of Neospora caninum in cattle from Western Java,Indonesia

Neospora caninum can cause fetal abortion and neonatal mortality in cattle, and is a cause of economic concern worldwide. This study aimed to determine the prevalence of Neospora caninum-specific antibodies in cattle from Western Java, Indonesia. Serum samples from 991 cattle from 21 locations were tested for antibodies to N. caninum by using an enzyme-linked immunosorbent assay (ELISA) on the basis of recombinant NcSAG1. The overall seroprevalence was 16.6%, ranging from 0 to 87.5% in the sampled locations. The results of this study indicate latent infection rates of sampled animals were different in each location. Further studies are necessary to elucidate the relationship between N. caninum infection and abortion in cattle, and to identify risk factors for infection in high-prevalence environments.     

Molecular analysis of aspermic Fasciola flukes from Korea on the basis of the nuclear ITS1 region and mitochondrial DNA markers and comparison with Japanese aspermic Fasciola flukes

It has been speculated that populations of aspermic Fasciola flukes in Korea and Japan have a close phylogenetic relationship. To evaluate this, we analyzed 33 Korean aspermic Fasciola flukes on the basis of nuclear ribosomal internal transcribed spacer 1 (ITS1) and mitochondrial NADH dehydrogenase subunit 1 (nad1) and cytochrome c oxidase 1 (cox1) sequences. Fh, Fg, and Fh/Fg types were detected in the ITS1 region and displayed the fragment patterns of F. hepatica, F. gigantica, and both species, respectively by a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Additionally, three concatenated haplotypes of nad1 and cox1(nad1/cox1) were detected, and 2 of these, Kor1/Kor1 (Fsp1/Fsp1) haplotype and Kor2a/Kor2 (Fsp2/Fsp2) haplotype, were shared by Korean and Japanese aspermic flukes. The Fst value (0.019), calculated using the concatenated sequences, indicated that Korean and Japanese aspermic Fasciola populations were genetically undifferentiated. Interestingly, a combination of the Fh/Fg type and Kor1/Kor1 haplotype was found at the highest frequency in Korean aspermic flukes, whereas the Fg type and Fsp2/Fsp2 haplotype combination was found at a conspicuously high frequency in Japanese aspermic flukes. This indicates that a founder effect caused by the introduction of infected hosts may have played a key role in the introduction of aspermic Fasciola flukes from Korea into Japan.     

Comparison of the insulin reaction of peripheral blood T cells between healthy Holstein dairy cows and JB during the periparturient period

To compare the changes in the insulin reaction of Holstein dairy cows and Japanese Black cows (JB) during the periparturient period, the insulin resistance test in vivo and lymphocytes proliferation with insulin in vitro were performed. Ten healthy Holstein dairy cows (Holstein group) and 10 healthy JB cows (JB group) used in this study were observed on days 60, 40, and 20 before calving and days 7 and 20 after calving. In insulin resistance reaction in vivo and in vitro, a low insulin-stimulated glucose disposal rate and lymphocyte proliferation with insulin were observed in the Holstein group compared with the JB group during the experimental period. An analysis of the lymphocytes cultured with insulin showed that the percentage of CD4+CD45R- T cells in the Holstein group was significantly lower than that of the JB group before day 20. These findings indicate that T cells reaction to insulin in healthy periparturient Holstein cows is lower than that in Japanese Black.