Biological Prime Quality of Colostrum and Calves Coming from Injection Zinc-Treated Dairy-Cows During Their Pregnancy

Veterinarni Medicina 37, 1992, 641-650

The effects of an administration of the Zindep inj. preparation (Biotika) were evaluated in pregnant dairy cows as exerted on specific weight total protein (TP) content, total immunoglobulin (IgC) and albumin (ALB) contents in colostrum. These parameters were also followed: calf's health, live weight, leucocyte (Lc) counts, T-lymphocyte (T-Ly) counts, contents of TPs, IgCs and ALBs in the blood serum of calves. Zinc concentrations were determined in colostrum, milk and calf blood serum. Our observations included 16 dairy cows in the seventh month of pregnancy in the second lactation and their calves in the winter feeding season. Eight experimental dairy cows were treated with the Zindep preparation in form of an injection to the neck muscles at a dose of 3 mg Zn/kg live weight in the mid-seventh month of pregnancy. Blood samples were taken from v. jugularis from all calves before their first drinking, on days 5, 15 and 30 of age. Colostrum, and/or milk samaples were obtained by drawing of the colostrum or milk from the udder quarters within 60 minutes after parturition, on days 5 and 15 of lactation. Zn levels at birth were 16.48+/-2.67 mumol/l in experimental calves and 13.84+/-3.19 mumol/l in control calves. Zincaemia decreased slightly in both groups on days 5 and 15 of age, but it was insignificantly higher in calves coming from Zindep-treated dairy cows. Zn levels in the blood serum on the 30th day of age were 18.45+/-2.44 mumol/l in experimental animals and 15.73+/-3.11 mumol/l in control animals. Zn content in the colostrum of experimental cows was 2.40+/-0.42 mg/l and in the control it was 1088+/-0.52 mg/l (P<0.05). On day 5 of lactation, Zn amounts in the milk of experimental dairy cows decreased to 0.95+/-0.12 mg/l and to 0.76+/-0.10 mg/l in the control (P<0.01). Zn levels in the milk of experimental cows on day 15 of lactation were 0.95+/-0.13 mg/l and in the milk of control group they were 0.82+/-14 mg/l. Colostrum specific weight from zinc-treated cows was 1,067.86+/-0.75 g/cm3 and 1,056.8+/-13.53 g/cm3 in the control. TP and IgC concentrations were 137.81+/-38.11 g/l and 110.13+/-29.91 U ZST, respectively, in the colostrum of experimental group, and 105.98+/-32.02 g/l and 85.53225.42 U ZST, resp., in control animals. Rosette-forming T-Ly lymphocytes represented 35.16+/-1.53 % in the blood of selected five experimental calves on day 15 of age, and 33.06+/-2.27 % in the blood of control calves. On day 30 of age, the T-Ly levels did not change significantly in the experimental and control calves (35.64+/-1.28 and 33.60+/-3.53 %, respectively). There were not any significant differences in leucocyte counts between the experimental and control group during the experiment. The largest differences in favour of the experimental calves against the control were observed in immunoglobulinaemia, albuminaemia, TP content and leucoyte counts before the calves drank colostrum for the first time. IgC content was not statistically higher in the blood serum of experimental calves than in the control during the whole experiment. The live weight of calves at birth was 42.28+/-3.92 kg in the experimental group and 40.43+/-5.78 kg in the control. A diarrhoeal syndrome was observed in three control calves till the 15th day of age, and four calves in the control group were treated to cure a respiratory syndrome till the 30th day of age. These results document that the Zindep administration to dairy cows in the mid-seventh month of pregnancy exerted positive effects on zincaemia of their calves, on Zn content in colostrum and milk, on biological prime quality of colostrum, postpartal weight and immunity mechanisms of calves

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