MATERIALS & METHODS
A total number of 68 newborn Holstein calves divided in four groups were used in the present study. Calves were randomly assigned to one of the following treatments:
- 1. Experimental Group 0.75+: 0.75 L of colostrum in 12h intervals, with 5 g/L of clinoptilolite immediately after birth (0h), at 12h and 24h after birth
- 2. Control Group 0.75-: 0.75L of colostrum in 12h intervals (0.75-), which represents the first control group
- 3. Experimental Group 1.5+: 1.5L of colostrum in 12h intervals, with 5 g/L of clinoptilolite immediately after birth (0h), at 12h and 24h after birth (1.5+)
- 4. Control Group 1.5-: 1.5 L of colostrum in 12h intervals (1.5-), which represents the second control group
The calves were born with high blood serum thyroid hormones concentrations (9.7-13.5 nmol/L for T3 and 201-235 nmol/L for T4).
At 6 hours after birth serum thyroid hormone levels increased in all groups, but become significantly lower in 48 hours after birth.
Clinoptilolite treatment could influence the rise in blood serum thyroid hormones concentration during the early postnatal period. This was most evident in the treated group of calves that received 1.5 L of colostrum:
- ⇰ Experimental Group 1,5+ (T3 – 6h): 11,7 ± 3,4 nmol/L
- ⇰ Control Group 1,5- (T3 – 6h): 19,4 ± 7,4 nmol/L