Nineteen claudin-16 (CL-16) deficient Japanese Black cattle, as well as two Japanese Black cattle with renal failure due to other causes, were studied with regards to the dynamics of vitamin A (VA) and retinol binding protein (RBP) and the development of long hooves. All of the CL-16 deficient cattle, except for three calves that were between one and six months of age, had long hooves (84%). The CL-16 deficient cattle were divided into normal and long-hoof groups, each of which was then compared to a group of 36 normal Japanese Black calves. The CL-16 deficient, long hoof group showed a significant increase in RBP, VA, urea nitrogen (UN), and creatinine (Cre) levels, while the CL-16 deficient, normal hoof group showed a significant increase in VA levels only. The RBP levels significantly and positively correlated with VA, UN, and Cre levels. VA levels were markedly high in calves of ages between five and thirteen months, during which the calves received feed containing VA. The non-CL 16 deficient cattle (with pyelonephritis and renal hypoplasia, respectively) also had long hooves as well as high VA and RBP levels. Based on the fact that the CL-16 deficient, normal hoof cattle were either young or affected with mild nephropathy, it was considered that the development of long hooves was not a CL-16 deficiency specific symptom, but rather attributable to persistent, severe renal dysfunction.

View full abstract

The relationship between changes of body condition score (BCS) during the pre and postpartum periods and reproductive performance was investigated in 158 cows in 31 herds. Cows were scored on a five-point scale (1=too thin to 5=obese in 0.25 increments) beginning at ?? 20 days before calving and then every 30 days until pregnancy was confirmed by rectal examination. Prepartum BCS was classified in three degrees (low : ?? 3.00, moderate : 3.25-3.75, high : ?? 4.00). Cows with higher BCS before calving tended to have a significant decrease of more than 1.25 points in postpartum BCS (p<0.05). Cows losing ?? 1.25 postpartum BCS points had significantly more days until first service and a longer open period (p<0.05) compared with cows losing 0-1.0 point. Cows with decreased pre and postinsemination BCS had significantly lower conception rates than cows with increased BCS (p<0.05). Therefore, these data suggest that high prepartum BCS decreases postpartum BCS and reproductive performance in dairy cows. They also suggest that decreased BCS pre and post insemination may lower the conception rate.

View full abstract

The residual toxicity of formaldehyde gas (FG) sterilization and neutralization equipment, "Holl Steri" (Asuka Medical), was evaluated biologically and compared with the conventional ethylene oxide gas (EOG) disinfectant process. The percentage of FG group motile spermatozoa, preserved in 0.25 ml straws for 6 hours, compared with the non-sterilized control group, decreased significantly (p<0.01) in the 6th hour. However, FG group had significantly higher survival rate than EOG group (2nd hour : p<0.01 ; 4th hour p<0.05). In bovine embryo culture for three days, the embryo survival rate decreased significantly (p<0.01) in FG group compared with control group of gamma ray sterilization on the 2nd day, and, at 2.5 days, all embryos were nonviable. However, compared with EOG group, embryo survival rate in FG group was significantly (p<0.01) higher on the 1 st and 2 nd days. In the in vitro maturation, fertilization and culture system of bovine oocytes for about ten days, the division rates into five or more-celled embryos and the blastocyst generation rates in FG group and control group of gamma ray sterilization were 60.0, and 20.0%, and 65.0 and 36.7%, respectively. Although rates were a little lower in FG group, there was no significant difference between groups. On the other hand, there was no embryonic growth in EOG group. These results suggest there was slight residual cell toxicity with FG sterilization and neutralization equipment compared with non-sterilizing or gamma ray sterilization, however there was very little residual toxicity compared with the widely employed conventional EOG sterilization.

View full abstract