抄録
We examined the relationship between concentrations of serum trace minerals and incidence of diseases in Japanese Black calves in 6 prefectures of the Tohoku district, north-east Japan. As our investigation areas, several major breeding areas of Japanese Black cattle were selected in each 6 prefectures, and the mortality rate and incidence of diseases around birth (from 240 days after fertilization to 30 days after birth) was investigated for all parturition (24,873). The concentrations in serum trace minerals (Fe, Zn, Cu, Se) were also determined in 179 calves of 100 days of age or younger. Areas of which serum Se concentrations were much lower than 4.0 µg/dL (lower limit of normal level) showed greater numbers of mortality caused by weak calf syndrome (WCS) and diarrhea than in the other areas, and also showed an increase in the mortality rate during the perinatal period (7.1%). The treatment cost per calf for diarrhea was expensive, and white muscle disease was recognized in 6 calves (0.7%). Serum Fe concentration was lower in area in which the calves historically showed smaller body sizes, at an average of about 25 kg birth weight, and WCS prevalence was significantly higher. These results suggest that the deficiency of Se, capable of trasplacental transfer, in the soil caused a series of deficiencies in the feed-mother cow and neonate, and consequently affected the mortality rate in the neonates. Furthermore, Fe concentration was thought to be influenced by breeding methods, Fe concentration in milk, and feeding methods (e.g. starting age of solid diet, presence of feed additives).
It is important to establish an effective feeding system for trace minerals that influence the calf health, noting the soil composition and feeding condition in each area.
