Aortic valve insufficiency caused by a hypoplastic aortic valve in a calf.

A 1-month-old crossbred calf was referred for examination due to marked systolic heart murmurs and poor growth. The heart murmur was most audible on the right side of the cranial thorax. Cardiomegaly was evident on chest radiography, and echocardiography demonstrated aortic regurgitation and decreased fractional shortening. Cardiomegaly, aortic root dilation and cardiac displacement were confirmed by computed tomography. At necropsy, the heart was enlarged, and all three aortic valve leaflets were irregularly shaped. In calves with chronic aortic insufficiency, remodeling displacement of the heart and aorta causes changes in the location and timing of heart murmurs. Therefore, aortic insufficiency cannot be ruled out when a systolic heart murmur can be observed in the right chest wall.

Changes in serum concentration and activity of diamine oxidase during the first month of life in calves.

The serum concentration and activity of diamine oxidase (DAO) in calves with or without diarrhea during the first month of life were examined. The serum DAO concentration was highest on day 0 after birth, and gradually decreased. No differences in serum DAO concentrations were observed between calves with diarrhea and control calves. In contrast, serum DAO activity was lowest on day 0 after birth, and gradually increased. Serum DAO activity in calves with diarrhea was lower than that in the control calves from day 20 after birth. These findings suggest that serum DAO activity and concentration are not correlated, and serum DAO activity is useful for assessing damage to the small intestinal mucosa in calves.

Cleaning procedures and cleanliness assessments of bucket milkers and suckling buckets on Japanese dairy farms.

Cleanliness of milking equipment is known to be important for the safety of dairy products and to prevent the spread of diseases among cows. We investigated the cleaning procedures of milking equipment and suckling equipment on Japanese dairy farms, and the cleanliness of bucket milkers, suckling buckets, milk receivers, and bulk tanks, using adenosine triphosphate (ATP) bioluminescence test. Bulk tanks (except one bulk tank) and milk receivers were washed by automated cleaning, but all bucket milkers and suckling buckets were washed by manual cleaning. Detergents were often not used to clean bucket milkers and suckling buckets. The log10 transformed relative luminescence units (LRLU) of equipment washed by manual cleaning was higher than equipment washed by automated cleaning. Clean surfaces (≤2.2 LRLU) were only observed on the bulk tank and the milk receiver. More than 50% of the LRLU of the mouthpiece, the rubber packing of claw, and the nipple of the suckling bucket were determined dirty. These results suggest that the cleanliness of the bucket milkers and the suckling buckets washed by manual cleaning was lower than that of the equipment washed by automated cleaning, and may be due to insufficient cleaning procedures.

Changes in luteinizing hormone pulse frequency and prolactin levels in bitches in response to estrus induction by cabergoline-its cases where it is delayed to induce estrus.

The effect of estrus induction by cabergoline on gonadotropin and steroid hormone responses was examined in anestrous bitches. Eleven beagles were used in the study; seven were included in the estrus induction group and four were included in the spontaneous estrus group. Cabergoline was orally administered to the estrus induction group at 5 µg/kg once daily for four weeks, or until hemorrhagic discharge was detected. The inter-estrus interval in the estrus induction group was significantly shorter than the previous estrus interval. Bitches that showed proestrus within four weeks of treatment showed increased luteinizing hormone (LH) pulse frequency and, subsequently, increased estradiol (E2) levels. Prolactin (PRL) levels declined promptly after treatment, except in one bitch that did not show proestrus during the cabergoline treatment period. There was a significant correlation between the time to proestrus induction and the reduction in PRL levels. A positive correlation was found between the LH levels two weeks after cabergoline administration and PRL reduction. This study demonstrates that an abrupt reduction in PRL is likely to be important for initiation of estrus in bitches. A reduction in PRL indirectly leads to an increase in LH pulse frequency, which regulates follicular development in bitches. However, if the period from the end of the previous estrus to the cabergoline treatment is short, it may take some time to show proestrus without increasing E2 levels, even if the LH level increases after cabergoline administration.

Survey of bovine foamy virus infection among cattle in Japan and comparison with bovine leukemia virus infection.

The prevalence of bovine foamy virus (BFV) infections in cattle on farms in the Kanto region of Japan was determined using agar gel immunodiffusion (AGID) test and polymerase chain reaction (PCR). Six out of 20 farms contained BFV-positive cattle. Furthermore, 16.7% (91/545) of all cattle tested positive for BFV. This suggested that BFV-infected cattle are widely prevalent in Japan. Positive results for BFV infection were consistent between AGID and PCR tests. Additionally, we tested for bovine leukemia virus (BLV) infections at nine farms, primarily those containing BFV-infected cows. At each farm, the infection rate of BFV was lower than that of BLV. Further, cattle that were PCR-positive but antibody-negative, indicating immune tolerance to BFV, were not detected.

Transient elastography: a novel, non-invasive method for the evaluation of liver stiffness and controlled attenuation parameter in cows.

This study investigated the use of transient elastography (TE) as a tool for the non-invasive evaluation of liver stiffness and controlled attenuation parameter (CAP) in cows. A total of 85 cows were used for this study. After the liver was located and subcutaneous tissue thickness was checked by means of ultrasonography, liver stiffness and CAP were measured using TE. At least 10 measurements were taken per individual cow. In addition, intraclass correlation coefficients were calculated for intra-rater and two-rater inter-rater reliability of liver stiffness and CAP measurement, and were evaluated. Of the 85 cows, 61 (71.8%) were measurable owing to their significantly less body weight and subcutaneous tissue thickness compared with those of unmeasurable cows. Liver stiffness showed no significant differences among sexes, ages, or breeds. CAP showed no significant differences among sexes and breeds. Intra- and inter-rater reliabilities for liver stiffness and CAP were almost perfect. Both liver stiffness and CAP could be quantitatively evaluated with good reproducibility in cows using TE, and CAP increased with the growth of the cows. However, evaluation was not possible in obese cows or cows with high values for subcutaneous tissue thickness or body weight.

Effect of feed restriction on hepatic estradiol metabolism and liver function in cows.

In this study, the effects of restriction feeding on the liver function, hepatic uridine diphosphate glucuronosyltransferase (UGT) activity, hepatic insulin-like growth factor (IGF)-1 mRNA expression and response to high-dose estradiol-17ß (E2) administration were investigated in non-lactating cows. Cows were assigned to either restricted feeding (30% of total digestible nutrient requirement) or ad libitum feeding of a dent corn-based concentrate and roughage for a 2-week feeding trial (Day 1=day of beginning the feeding trial). On day 14, a high-dose E2 administration study was carried out to examine plasma E2 levels as an indicator of hepatic E2 metabolism. Plasma E2 concentration in the restricted feeding group was consistently higher after high-dose E2 administration than in the control group. In addition, indocyanine green half-life value was prolonged by restricted feeding for 13 days, and increased liver triglyceride concentration and decreased liver UGT activity were caused by this restriction over 14 days. Restricted feeding did not affect plasma IGF-1 concentration or hepatic IGF-1 mRNA expression. These results suggest that two weeks of restriction feeding led to accumulation of triglyceride, decreased liver blood flow, and slightly impaired liver function, which in turn slowed down the hepatic metabolism of E2 without significantly impacting hepatic IGF-1 production.

Isolation of bovine foamy virus in Japan.

Bovine foamy virus (BFV) is endemic in many countries, but has not been reported in Japan. A syncytium-forming virus was isolated from peripheral blood leukocytes of clinically healthy cattle on a farm in Kanagawa prefecture during a periodic epidemiological survey of viral diseases. The isolate was propagated in primary fetal bovine muscle cells and subsequently passaged in Madin-Darby bovine kidney cells. Since the isolate appeared to be distinct from the viruses with syncytium-forming ability previously isolated in Japan, we attempted to identify it using genomic analyses and electron microscopy. A phylogenetic analysis revealed that the isolate belongs to the bovine foamy virus cluster and is highly similar to a BFV strain isolated in China. A sero-epidemiological survey was performed using agar gel immunodiffusion test with the isolated virus as the antigen, and five of the 57 cattle tested were found to be seropositive.

Development of ovarian diseases in dairy cows with a history of fatty liver, and their prognosis.

In the present report, the incidence and prognosis of ovarian diseases were evaluated in correlation to the grades of the fatty livers (FL). 233 animals were diagnosed with a FL, based on fat deposition of >10% into the hepatic parenchyma obtained from liver biopsy, and were eventually cured of the FL. These 233 animals were classified into mild group (n=99: hepatic fat deposition rates ranging from 10 to <30%), moderate group (n=56: hepatic fat deposition rates ranging from 30 to <60%) and severe group (n=78: hepatic fat deposition rates of >60%). The incidence of ovarian diseases and the culling rate were, respectively, 40.0% and 10.0% in mild group, 58.3% and 37.5% in moderate group, and 84.9% and 69.7% in severe group. The incidence of ovarian diseases and the culling rates in severe group were significantly (P<0.05) higher than those in mild and moderate groups. It was, therefore, concluded that the elevated incidence of ovarian disease and culling rates tend to be dependent on the higher severity scores of the fat deposition rates in dairy cows with FL and that cases with severe FL, with a fat deposition rate of 60% or higher, were greatly associated with death and culling.

Analysis of the equine ovarian structure during the first twelve months of life by three-dimensional internal structure microscopy.

A three-dimensional internal structure microscopy (3D-ISM) can clarify the anatomical arrangement of internal structures of equine ovaries. In this study, morphological changes of the equine ovary over the first 12 months of life were investigated by 3D-ISM in 59 fillies and by histological analysis in 2 fillies. The weight and volume of the paired ovaries initially decreased from 0 to 1 months to 2 to 3 months of age and then significantly increased at 8 to 12 months of age. The ovulation fossa was first observed around the 3rd month and became evident after the 6th month. The number of follicles with a diameter of ≥10 mm and the diameter of the largest follicle increased gradually after 6 months of age. On a volume basis, the medulla accounted for nearly 90% of the whole ovary at 0 to 1 months of age, but significantly decreased from 2 to 3 months of age. The volume of the cortex increased progressively after birth and reached approximately 60% of the total volume at 8 to 12 months of age. This significant development of the cortex coincided with the increased number and size of large follicles observed from 6 months of age. These results suggest that the development of the cortex plays a role in the maturation of the follicles and the equine ovary undergoes substantial morphological changes postnatally until puberty.

GnRH analogue treatment on LH surge day 0 followed by single transvaginal artificial insemination with frozen semen on day 5 in bitches.

Reproductive parameters were evaluated in 19 and 14 estrous beagles that received 100 µg of gonadotropin-releasing hormone (GnRH) and saline treatment, respectively, on the day of luteinizing hormone (LH) surge (Day 0; estimated by serial progesterone assay) and balloon catheter-aided single transvaginal artificial insemination of frozen semen on Day 5. Although the conception rate and litter size were similar between the GnRH and saline groups, the concentration of LH peak was significantly higher in GnRH-treated bitches (P<0.01). In addition, the actual LH surge did not occur on the estimated Day 0 in one saline-treated bitch. In clinical practice that daily progesterone assay is difficult, administration of GnRH on estimated Day 0 would be recommended to induce or enhance the LH surge for timely and successful insemination.

Evaluation of transcervical insemination using frozen semen by flexible endoscope in dogs.

We evaluated transcervical insemination (TCI) using frozen semen by flexible endoscopy in dogs. Eight female and eight male beagles were used in this study. A flexible endoscope and a washing tube were used for TCI. A tracheal tube was used as an alternative to the penis and was an auxiliary for inserting the flexible endoscope. The mean time required to insert the washing tube into the external os of the uterus after inserting the endoscope into the tracheal tube was 7.5 min. Slight or mild pain was observed in all bitches during TCI. However, TCI could be easily performed with retention in all bitches and without sedation anesthesia. The tracheal tube was useful to ensure the visual field using air sufflation. Clinical signs suspicious of infection were not observed in any bitches from the TCI to the pregnancy diagnosis. The conception rate was 87.5%, and the mean number of fetuses was 6.3. TCI using a flexible endoscope in bitches was performed quickly with minimal invasiveness. We present a new method of TCI in dogs. This method should be studied in small and large breeds to obtain more detailed results.

Relationship between indocyanine green clearance test and feed intake and impaired hepatic function in dairy cows.

The purposes of this study were 1) to examine changes in the indocyanine green (ICG) clearance by feeding and 4-day fasting in dry cows, and (2) to investigate the relationship between ICG clearance and blood chemistry profile in postpartum cows. In 3 dry cows, post-feeding ICG half-life (T(1/2)) was shorter than the pre-feeding value, and post-fasting T(1/2) was longer than pre-feeding and post-feeding values. In 16 lactating cows, T(1/2) value at 2 weeks postpartum showed positive correlations with AST, T-Bil and γ-GTP. These results suggested that ICG clearance correlated with T-Bil and liver enzymes can be sensitive and accurate diagnostic marker for impaired liver function in dairy cows. In addition, ICG clearance is greatly affected by feeding and fasting.

Effect of short-term fasting on hepatic steroid hormone metabolism in cows.

In the present study, the effect of 4-day fasting on steroid hormone metabolism in the liver and secretion of LH was examined in cows. Six non pregnant, dry Holstein cows were used. The estrous cycle was synchronized in all cows using CIDR-Ovsynch. Cows were allocated to a control group (n=3) and a fasting group (n=3). In the fasting group, cows were fasted for four days from day -4 to day -1 (day 0=day of 2nd GnRH injection) but otherwise were fed ad libitum. The experiment was repeated in a crossover design after an interval of about one month. The peripheral progesterone (P(4)) concentration in the fasting group was significantly higher than in the control group on day -1 and 0. The peripheral estradiol-17ß concentration in the fasting group was also significantly higher than in the control group on day -1 and 0. The portal vein P(4) concentration in the fasting group was significantly higher than in the control group. On day 0, there was no difference in LH secretion between groups. The mean percentages of lipid droplets in liver cells in the fasting group were significantly higher than in the control group on day 0. These results suggest that short-term fasting leads to reduced hepatic steroid hormone metabolism by accumulation of fat in the liver, which causes high peripheral steroid hormone concentrations.