Effect of two low doses of prostaglandin F_2α on luteolysis in dairy cows

In this preliminary study, we determined the effect of a modified method involving the administration of two low doses of prostaglandin F2α (PGF2α) at an interval of 24 h on luteolysis in dairy cows, and compared it with the standard single-dose method. Twenty-six cows were assigned to three groups treated with two low doses (TLD group, n = 10), one standard dose (SD group, n = 10), and one low dose (OLD group, n = 6) on day 9 to 10 of the oestrous cycle (day 0 = the day of PGF2α administration). Their serum progesterone (P4) levels and corpus luteum (CL) sizes were measured daily from day 0 to 4 to assess CL regression. The results indicated that the proportion of complete luteolysis, indicating a P4 value ≤ 1 ng/mL on day 3, was higher in the TLD group (100.0%) than in the SD (60.0%) and OLD (66.7%) groups. Ultrasonically detected changes in the CL area correlated with the shifts in the P4 values in both the TLD and the SD groups. The remaining CL area was significantly smaller in the TLD group (17.8% ± 3.3%) than in the SD or OLD group on day 4. Thus, we concluded that the proportion of luteolysis in cows was increased with two low doses of PGF2α as compared to a single PGF2α dose, indicating the necessity of the second dose of PGF2α. However, further studies with larger sample sizes in the field are required

In vitro effects of nonesterified fatty acids and beta-hydroxybutyric acid on inflammatory cytokine expression in bovine peripheral blood leukocytes

Negative energy balance (NEB) occurs in dairy cows during the transition period, during which time the blood concentrations of nonesterified fatty acids (NEFA) and metabolic ketones such as β-hydroxybutyric acid (BHBA) are elevated. These increased levels may disrupt immune functions and are regarded as risk factors associated with postparturient inflammatory disorders. Therefore, the aim of this study was to investigate the effects of NEFAs and BHBA on inflammatory cytokine expression in bovine peripheral leukocytes in vitro. Peripheral blood mononuclear cells (PBMCs) and peripheral polymorphonuclear leukocytes (PMNLs) were collected from 16 Holstein cows and treated for 4 h with NEFA (0.1, 0.6, and 1.5 mM) or BHBA (5 and 10 mM), alone or combination with lipopolysaccharides (LPS, 1 µg/mL). The expression levels of the inflammatory cytokines TNF-α, IL-1β, IL-6, IL-8, and IL-10 were then determined. The results indicated that PBMCs and PMNLs responded to NEFA but tolerated BHBA. NEFA treatment dose-dependently induced the expression of TNF-α, IL-1β, IL-8, and IL-10 in PBMCs and that of IL-1β, IL-6, IL-8, and IL-10 in PMNLs. Combination treatment of LPS with NEFA further increased the levels of IL-10 expression in PBMCs and IL-1β and IL-6 expression in PMNLs. Taken together, these findings suggest that NEFA and BHBA enhance the expression of inflammatory cytokines in PBMCs and PMNLs and may disrupt the immune regulation of peripheral leukocytes, leading to an increased risk of inflammatory disorders. Preventing increases in blood NEFA concentration may thus help to reduce the risk of inflammatory disorders in dairy cows during the transition period

The first discovery of severe fever with thrombocytopenia syndrome virus in Taiwan

Severe fever with thrombocytopenia syndrome (SFTS), an emerging tick-borne zoonosis, has been rapidly spread in many Asian counties since 2010, which raises the great concern in East Asia. Nevertheless, the infection status of SFTS in Taiwan remains unclear. To investigate the existence of SFTSV in Taiwan, a total of 151 serum samples collected from 31 sheep, 63 bovine and 57 dogs were enrolled this study. Furthermore, 360 adult female Rhipicephalus microplus were also included. One-step RT-nested PCR and IgG ELISA were conducted to test SFTSV specific RNA and antibodies, respectively. The result provided the first evidence of the existence of SFTSV RNA and antibodies in ruminants and ticks in Taiwan