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Essential and non-mutagenic elements in raw ewe milk

Toman Robert, Pšenková Martina, Imrich Ivan, Hluchý Svätoslav, Almášiová Simona

Science, Technology and Innovation

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2021

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Vol. 14, no. 3-4

34--44

EN

The monitoring of metals and other chemical elements in the basic sources of diet, mainly for children, is very important for preventing health issues. The aim of this work was to determine the concentration of selected essential (Ca, K, Mg, Mo, Na, Zn) and non-mutagenic elements (Ag, Al, Ba, Li, Sb, Sr) in ewe milk from the Orava region in northern Slovakia. Twenty milk samples were analysed in June and August using an inductively-coupled plasma optical emission spectrometry. The differences in elements concentration between the seasonal periods were not significant (p < 0.05), except for lithium (p < 0.05). The essential elements concentration was within the recommended levels, while the non-mutagenic and potentially toxic metals consist was under the permissible limits. However, there were found very strong and significant relationships between the elements which may suggest the synergistic / additive or antagonistic effects of some elements.

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Effect of temperature and relative humidity on the milk production of dairy cows

Imrich Ivan, Toman Róbert, Pšenková Martina, Mlyneková Eva, Kanka Tomáš, Mlynek Juraj, Pontešová Barbora

Science, Technology and Innovation

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2021

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Vol. 13, no. 2

22-27

EN

The aim of this study was to evaluate the influence of environmental housing conditions on the milk yield of dairy cows. Measurements were taken in the summer period from June to September, 2020 and in the winter period during January, 2021 on a large-capacity farm of Holstein Friesian cattle. Cows were housed in free stall barn with the lying boxes and selected during the second or third lactations, in the summer period from the 51st day to the 135th day and in the winter period from the 64th day to the 120th day of lactation. The average temperature in the housing was 23°C in summer, and 7.05°C in winter. The average THI (thermal humidity index) value in summer was 70.43, but during the day the THI values sometimes reached 75. The dairy cows were therefore exposed to heat stress during summer. Increasing THI and temperature values negatively affected the milk yield, as there was a negative correlation between both THI and milk yield (r = −0.641; p < 0.01) and temperature and milk yield (r = −0.637; p < 0.01). Milk production in winter was at 58.77 kg per day and in summer at 49.55 kg per day. In the summer, the milk had a significantly lower content of fat (p < 0.05), proteins (p < 0.001), lactose (p < 0.001), minerals (p < 0.001) and conversely, a higher number of somatic cells (p < 0.01). These results show that worse environmental conditions during the summer negatively affected the level of milk yield and the composition of the cows’ milk.

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Changes in the concentrations of selected toxic and essential elements in ewe milk from area with a potentially undisturbed environment

Pšenková Martina, Toman Róbert, Imrich Ivan, Hluchý Svätoslav

Science, Technology and Innovation

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2021

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Vol. 13, no. 2

28--34

EN

The aim of this study was to evaluate the effect of lactation on the concentration of selected essential and toxic elements in sheep milk forma area of Slovakia with potentially undisturbed environment and to find the actual contamination of selected area, in view of its environmental character. The research was conducted with 400 sheep (Tsigai breed), where the milk samples were taken during the lactation periods (early, middle and late lactation stage). Sheep were reared on the extensive pastures, reared indoors afterwards, fed with pasture ad libidum. Milk samples were collected after morning and afternoon milking. The samples of milk were analysed toxic and essential elements (Ca, Se, Mg, Zn, Fe, Cu, As, Cd, Hg, Ni, Pb) by the method of atomic absorption spectroscopy (AAS). The macro elements concentration in milk changes following the stages of lactation (p < 0.05). There was found that Ca milk concentration increased gradually in the following stages of lactation while Mg, Se, and Fe only in the last stage of lactation. With order hand, the milk concentration of Zn was the highest during summer (p < 0.05). Simultaneously the contents of essential elements (Cu) and toxic elements (As, Cd, Hg, Ni, Pb) in milk were very low, below the limit of quantification. In conclusion, ewe’s milk from potentially undisturbed environmental areas of Slovakia is safe and poses no risk to consumer health, and is suitable for use directly or in dairy processing.