Respiratory, gastrointestinal, urological and reproductive diseases account for a large part of bovine production diseases. All of these diseases develop on the mucosal surfaces of the respective organs. The mucosa-associated lymphoid tissue（MALT）is a secondary lymphoid tissue providing a specific immune system in the mucosa, and understanding the bovine MALT is an important part of the efforts toward the control of bovine production diseases.

　In recent years, research on the innate immune system, which provides early immunity in infection, has progressed rapidly, and pathogen recognition mechanisms and the diversity of innate immunity cells have been elucidated. We now know that innate immune cells in the mucosal immune system have a unique nature and that the interactions between the mucosal immune system and innate immune system are indispensable. The concept of protective immunity against infection in cattle, however, is still discussed from the perspective of the acquired immune system primarily based on antibody titers in blood. We will discuss how we can control bovine production diseases using the mucosal immunity and innate immunity.

　Endometritis is one of the causes of poor reproductive performance in dairy cattle. The objectives of this study were 1）to investigate the prevalence of clinical endometritis based on vaginal mucus scoring（VMS）determined by vaginoscopy and 2）to determine possible risk factors associated with its occurrence in Japanese dairy herds. Holstein Friesian cows（n=180; total number of lactations, 251）were examined with vaginoscopy between 21 and 90 d postpartum to detect clinical endometritis and were classified by the disease severity based on the 4-point VMS system: 0（no or clear mucus）; 1（mucus containing flecks of white or off-white pus）; 2（discharge of less than 50% pus）; and 3（discharge of more than 50% pus）. VMS of 1 or higher was defined as clinical endometritis. The prevalence of clinical endometritis at 21-28 d, 29-40 d and 41-90 d postpartum was 41.9%（13/31）, 25.5%（26/102） and 21.2%（25/118）, respectively. Logistic regression analysis revealed that the retention of fetal membranes（OR = 3.96; p<0.01）and early postpartum disease within 30 days of parturition（OR = 2.02; p<0.05）were significantly related to the occurrence of clinical endometritis. The results of this study suggest that clinical endometritis was present in up to 20% of cows at 40 to 90 d postpartum and that vaginoscopy may be suitable for field diagnosis of endometritis. Cows with a history of retention of fetal membranes or early postpartum disease within 30 days may require proactive examination, diagnosis and treatment to restore uterine health and fertility.

　The effects of long-distance transportation on body weight and hematological and serum biochemical parameters were investigated in ten Japanese Black heifers transported 2,078 km （1,130 km by road and 947 km by ferry） from Miyazaki to Hokkaido over 62 hours on a cattle transport vehicle. The mean body weight showed a significant decrease of 9.6% after transport （mean ± standard deviation, 283.5 ± 29.6 kg before and 256.2 ± 26.5 kg after transport; p<0.001）. Red blood cell count, hemoglobin, hematocrit, mean corpuscular hemoglobin and serum nonesterified fatty acid increased after transport （p<0.05）. On the other hand, serum levels of total cholesterol, blood urea nitrogen, glucose, aspartate aminotransferase, vitamin A, magnesium and high-density lipoprotein cholesterol were significantly lower after transportation than before transportation （p<0.05）. These changes indicate insufficient nutrient intake and dehydration. Thus, it is suggested that decreased body weight after transportation could be related to the decrease in dry matter and water intakes.

　Piroplasmosis in cattle has become a forgotten disease since its decline in incidence. The present case was a 10-year-old Japanese Black cow, which presented with anorexia, pale mucous membrane and erythrocytes infected with Theileria. Wild deer and young ticks（Haemaphysalis megaspinosa）had been sighted in the pasture. Diminazene aceturate（DDA）was administered at 1 g/head once daily for four days after the initial presentation but did not change the number of infected erythrocytes and hematocrit. On Day 6, since clinical symptoms did not improve, 50 mℓ of 1% acriflavine was administered intravenously. On Day 7, the cow’s condition improved with a red blood cell count and hematocrit of 133 × 10⁴/μℓ and 12.9%, respectively. Since acriflavine is not available for veterinary use, its effect against Theileria infection is not well known. The result of this study suggests that acriflavine may be considered when DDA is ineffective. The occurrence of piroplasmosis has decreased through the eradication of ticks using a pour-on insecticide; however, eradication is considered incomplete. Since wild animals in contaminated areas can carry arthropod vectors for piroplasmosis, the importance of preventive measure should be emphasized with the increasing number of wild animals.