THE EFFECT OF AGE ON THE CHANGES OF COPPER AND IRON CONCENTRATIONS IN THE BLOOD-SERUM OF CALVES

Microelements, being components of various ferments, hormones, vitamins and other substances, take part, within the metabolic processes, in growth, reproduction, immunologic activity, efficiency and particularly, not last in the general health condition of an organism. 21 or 24 calves of the Black Pied breed, reared in the Agrokomplex Nitra, were selected at random in the trials. The blood of calves was taken by puncture from vena jugularis regularly three hours after morning feeding at following ages: 0, 1, 2, 3, 5, 7, 14, 21, 28, 35, 49, 63, 91, 119, 147 and 175 days. Blood serum was obtained by centrifuging the blood at 3000 revolutions per minute during 30 minutes. The copper and iron contents were determined photometrically by help of the Bio-La-tests. The variation-statistical evaluation of copper and iron contents is stated in the Tab. I. The average level of Cu in the I trial ranged from 9.15 (0 day) up to 17.63 (21st day) mu-mol . 1(-1); in the II trial from 10.19 (0 day) up to 18.40 (175th day) mu-mol . 1(-1). The average level of Fe in the I trial ranged from 14.33 (35th day) up to 29.16 (0 day) mu-mol . 1(-1); in the II trial from 15.01 (35th day) up to 27.94 (0 day) mu-mol . 1(-1). The testing differences of Cu and Fe concentrations are stated in Tabs II and III. Most of significant and highly significant differences were recorded, as to Cu, in the first trial between the 0 day and the other age categories, in the second one between the 0, 1st, 2nd, 3rd days and the other age categories. Very rare were the differences between the other age categories, too. As to Fe, most of highly significant or significant differences were recorded in both the trials especially between the 0, 1st, 2nd days and the other age categories, while in the second trial the significant and highly significant differences were also recorded between the 3rd and 21st to 175th days; the 5th and 28th to 63rd days and the 7th and 21st to 119th days. The other differences were statistically insignificant. The age dynamics of copper and iron are stated in figs 1 and 2. In both the trials strong correlation dependence of copper concentration on age was recorded (0.932, or 0.981). The highest increase of its concentration occurred, as a rule, during the first seven days of life. From the age of 14 days up to the end of study the copper concentration kept almost the constant level. The strong correlation dependence was also noticed between the iron concentrations and age (0.978, or 0.985). As to iron, the largest changes of its concentrations were noticed during the first 14 days, when almost a double increase took place. From the 21st day of age its concentration kept more or less steady level. Strong correlation dependences of Cu and Fe on age and their contradictory tendency stimulated us to calculate reciprocal correlation dependences between Cu and Fe (-0.866, or -0.920). On the basis of the results obtained as well as of widely known findings it is possible to come to the following conclusion: 1. The age dynamics of Cu and Fe as well as the variation-statistical evaluation of their content indicate the level of concentration of these elements in calf body. In both the trials the strong correlation dependence of copper and iron on age was recorded (I(yx) > 0.9). At the same time we recorded the contradictory tendency of copper and iron concentrations. 2. We recorded strong negative highly significant correlation dependence between the concentrations of Cu and Fe (r(xy) < -0.8). Synergic relations between copper and iron were proved likewise. 3. The largest changes in the dynamics of studied parameters take place, as a rule, during the first 7 to 14 days of calf life. From this viewpoint the period from the birth up to 114 days of age could be regarded as "the critical period" of calf life, what is in full agreement with literatura data. 4. It follows from both the results obtained and the literature data that the early postnatal period of the life of calves is, as to the development of their immunity system, health condition, weight gains and also the concentrations of certain parameters (iron especially) in serum, in fact the continuation of their prenatal development. It is evident that the feeding of dairy cows by microminerals supplements especially before the calving is very important, particularly as far as the iron is concerned. This provision could generally improve the health condition (especially decrease the occurrence of anemia, or scours) and consequently the parameters of calf-rearing (mainly by the decrease of mortality and the increase of gains) likewise.