AbstrACt:The object of an experiment was inorganic and organic forms of zinc, copper and manganese applied in mineral mixtures to dairy cows. The experiment was carried out on 90 cows with average milk yield for previous lactation of about 9 500 kg milk. The cows received mineral mixtures containing inorganic or organic forms of zinc, copper and manganese for 6 weeks before calving and during the first three months of lactation. The application of microelements as bioplexes in amounts covering 30% of daily requirements of cows had a positive effect on an increase in colostrum dry matter content from 20.9 to 23.35% as well as on the concentration of protein and fat, and the level of minerals -calcium, phosphorus, magnesium, zinc and copper. In cows' milk in the 2 nd and 3 rd month of lactation there were no differences in contents of minerals. However in the blood serum of cows in the 1 st and 2 nd month of lactation an increase in calcium concentration from 1.96 to 2.14 g/kg was observed while the content of phosphorus also increased average from 1.76 to 2.22 g/kg in the first trimester of lactation.

The aim of the study was to evaluate the effects of dietary unprotected fish oil on milk yield, fatty acids content and serum metabolic profile in dairy cows. Forty lactating Polish Holstein-Friesian cows were assigned to two groups. The cows were fed a control basal diet (C group), or a basal diet containing 2% addition of fish oil on mineral carrier (FOM group) during a 8-week period. Supplementing FOM diet of dairy cows had no significant effect on milk fat, milk protein, milk lactose concentration and somatic cells count, but increased the milk yield (36.5 kg/d), (p < 0.05) compared with the control cows (34.28 kg/d). We observed an increase (p < 0.05) in body condition scoring between C and FOM groups. Additionally, higher levels of non-esterified fatty acids and β-hydroxybutyrate acid were noticed in FOM group after 8 weeks of the experiment; however, these serum parameters still were in the reference range. Concentration of insulin was higher (30.40 μU/ml; p < 0.01) in the FOM group compared with the control group (14.03 μU/ml). In the FOM group, significant increase (p < 0.01) in long-chain fatty acids, mainly cis-9, trans-11 CLA and n-3 fatty acids (eicosapentaenoic and docosahexaenoic acids) was observed. The obtained results demonstrated that addition of fish oil to cows' diet could profitably modify the fatty acids in cow's milk.

The aim of the investigations was to assess the influence of supplementation of cow rations with zinc, copper and manganese given in the form of bioplexes during the perinatal period. Colostrum ąuality and immunoglobulin level in calf serum were evaluated. Total protein and its fractions in colostrum from the first milk as well as in calves' blood serum from the 2 M and 35* day of life were determined. Additionally, the total immunoglobulin index in week 3-4 of life (Ng M) was calculated. All calves were well supplied with colostral lactoimmunoglobulin. The highest level of y-globulin (12.5 g/L) was found in group 111 and resulted from the higher level of this fraction in colostrum (93.6 g/L). The value of IIg M-0.54 found in 111 group confirms that the newborn calves are well protected by colostrum.

The aim of the presented study was an estimation of the zinc bioavailability derived from amino acid complexes with methionine, lysine and glycine in growing lambs. 48 lambs, Polish Merino × Romanowski × Charolaise crossbreed, at age about 10 weeks and average body weight of 20 kg were randomly divided into 4 experimental groups. Animals were kept collectively and fed with concentrate and hay in amount: 0.7-1.2 and 0.3-0.5 kg/day/head, respectively. After rearing period 6 rams from each group with average body weight of about 30 kg were divided into digestibility-balance experiments. At the end of the experiment the blood samples were taken, then from each group 8 lambs were chosen, killed and during dissection tissue samples were taken (liver, pancreas, kidney and rib bone). In tissue samples as well as in fodders and excrements the content of zinc was determined. Obtained data in digestibility experiments allowed on calculation of apparent absorption and retention of zinc and the level of Zn determined in tissues' samples were used to the estimation of bioavailability of zinc from different ones applied in experiment sources.Apparent absorption and retention of zinc were higher (P≤0.01) in lambs receiving in mixtures amino acid complexes of zinc than in animals from the control group. The higher content of zinc in soft and hard tissues of lambs which received organic forms of zinc might indicate better assimilation and bioavailability of zinc from these forms than from oxide. Among tested organic forms of zinc, the zinc-lysine complex was characterized as having the most advantageous property. Tierzucht 54 (2011) 4, 391-398, ISSN 0003-9438 © Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany Kinal and Slupczynska: The bioavailability of different chemical forms of zinc in fattening lambs 392 Ende

One thousand one-day-old broiler chicks were divided into 5 experimental groups: the control groups received an antibiotic in their feed, the remaining groups-3% dried milfoil (Achillea millefolium L.) and St. Johnswort (Hypericum perforatum L.) herbage and lovage roots (Levisticum officinale Koch) mixed in various proportions. Body weight gain and feed utilization over a 9-week period of the experiment were similar in the experimental and control groups. A beneficial effect of milfoil on body weight gain of chicks was found. Milfoil in combination with St. Johnswort affected positively the sensory characteristics of meat.