Effect of temporary cessation of milking and estradiol combination on the antimicrobial components in goat milk.

A temporary cessation of milking is widely used in Japan to treat mastitis in dairy cows. Exogenous administration of estradiol (E2) is known to inhibit milk production in dairy cows. Therefore, we aimed to evaluate the effects of the temporary cessation of milking in combination with E2 administration on the antimicrobial components of goat milk. Twelve goats, divided into two groups-with and without E2 injection (E2 and control group, respectively), were subjected to cessation of milking in both udder halves for 3 d (day 0-2). Milk yield in the E2 group was significantly lower than that in the control group on days 7 to 10. The concentrations of cathelicidin-2, IgA, and lactoferrin in the E2 group were significantly higher than those in the control group. These results suggest that the temporary cessation of milking with simultaneous E2 administration leads to a higher concentration of certain antimicrobial components in milk than that observed after using cessation of milking alone. Thus, this combination may contribute to a stronger innate immune system and a faster recovery from mastitis, and might prove to be an alternative to antibiotic treatment upon further research.

Association of endometritis and ovarian follicular cyst with mastitis in dairy cows.

The occurrence of multiple metabolic and inflammatory diseases in dairy cows is higher during the periparturient period, which may be triggered by bacterial components, but not a viable bacterium. This study aimed to determine the association of endometritis and ovarian follicular cyst (OFC) with mastitis in dairy cows. Ninety-eight Holstein dairy cows were clinically examined for endometritis and OFC approximately 30-50 days after calving. Blood and milk samples were collected for the determination of milk somatic cell count (SCC); milk interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNFα), and interleukin-8 (IL-8) concentrations; and plasma haptoglobin (Hp) and lipopolysaccharide-binding protein (LBP) concentrations. Of the 98 dairy cows included in this study, 12 were diagnosed with endometritis and 37 cows were identified as OFC-positive, whereas the remaining 49 cows were healthy (without endometritis or OFC). The average and maximum SCCs and plasma Hp and LBP concentrations were not significantly different between the healthy cows and those with endometritis or OFC. However, when the maximum SCC was classified as <300, 300-1,000, or >1,000 × 103 cells/ml, the percentage of cows with the maximum SCC <300 × 103 cells/ml was significantly lower in the endometritis and OFC-positive groups than in the healthy group. These results suggested that cows with endometritis and OFC during the postpartum period exhibit high SCC, indicating that some bacterial components can be transferred between organs.

Translocation of intrauterine-infused bacterial lipopolysaccharides to the mammary gland in dexamethasone-treated goats.

Our previous study showed that intrauterine-infused lipopolysaccharide (LPS) can be translocated to the mammary gland to induce weak inflammation. This study aimed to determine whether dexamethasone treatment facilitated the translocation of LPS from the uterus to the mammary gland to induce a heavy inflammatory response. Sixteen goats were divided into control and LPS groups, subjected to daily dexamethasone administration before saline or LPS infusion. Milk and blood samples were collected before and after LPS infusion to determine the milk yield and somatic cell count (SCC) and blood leucocyte count (BLC), cytokines, antimicrobial peptides and serum amyloid A (SAA) concentrations. Mammary gland tissues were collected from two goats before and 24 hr after LPS infusion for immunohistochemical analysis of LPS. The mean SCC in the LPS group was significantly higher, whereas the milk yield was significantly lower than that in the control group after LPS infusion. The mean BLC in the LPS group was significantly lower than in the control group after LPS infusion. Furthermore, milk concentrations of IL-1ß, S100A8 and lactoferrin were higher in the LPS group than in the control group after infusion. LPS was detected in the connective tissues and inner alveolar spaces of the mammary glands 24 hr after LPS infusion. We concluded that dexamethasone administration facilitated the translocation of intrauterine-infused LPS to the mammary gland, where it induced an inflammatory response. Therefore, LPS translocated from other organs, such as the uterus, can induce heavy inflammation in the mammary gland under immunosuppressive conditions.