Serum selenium and vitamin E concentrations in indigenous Korean calves with neonatal weak calf syndrome.

Neonatal weak calf syndrome (NWCS) is characterized by reduced vigour in neonatal calves, leading to difficulties in standing and suckling. This study aimed to evaluate whether serum selenium and Vitamin E (VE) concentrations were associated with NWCS. The study included 29 indigenous Korean (Hanwoo) beef calves: 10 healthy and 19 weak (14 surviving, 5 non-surviving), based on standing and suckling ability. These calves were recruited from 19 farms. Healthy calves suckled an adequate volume of colostrum while weak calves (who suckled inadequately) were fed 1-2 L of frozen colostrum or colostrum replacer; all within 2 h of birth. One blood sample was collected from each calf at least 4 h after last feeding (within 18 h after birth), and serum selenium and VE concentrations were analysed. The results showed no significant difference in serum selenium concentrations between healthy and weak calves but, VE concentrations were significantly lower (and deficient) in weak calves. Among the weak calves, non-survivors also showed numerically lower levels than survivors. These findings suggest an association between calf blood VE concentrations and NWCS but not with calf blood selenium concentrations. It is hypothesised that the NWCS was caused by foetal VE deficiency as despite additional colostrum feeding weak calves (NWCS) still had significantly lower postcolostral serum VE concentrations than healthy calves. As VE is involved in muscle function, immunity, and oxidative stress regulation, ensuring adequate maternal VE supplementation and timely colostrum intake may help reduce both the impact of VE deficiency on NWCS and the impact of NWCS on VE status in calves with low maternal-foetal VE reserves where prompt colostrum feeding is not practised, as is often the case with beef calves.