The content of minerals in milk of small ruminants

T. Michlová¹*, A. Hejtmánková¹, H. Dragounová² and Š. Horníčková¹

¹Czech University of Life Sciences Prague, Faculty of Agrobiology, Food and Natural Resources, Department of Chemistry, Kamýcká 129, CZ 165 21 Prague, Czech Republic
²Dairy Research Institute Ltd, Ke dvoru 791/12A, CZ 160 00 Prague, Czech Republic
*Correspondence: michlova@af.czu.cz

Abstract:

The aim of this study was to determine and compare the content of sodium, potassium, calcium, magnesium, zinc, copper, lead, and cadmium in sheep and goat milk of different breeds from 9 farms in the Czech Republic (herds of 18–330 goat´s heads and 30–380 sheep heads). Pool samples of milk were collected once a month (April – September) during lactation in the years 2011–2013. The content of minerals was determined using atomic absorption spectroscopy. Most of the analyses of the contents of Cd and Pb were below the limit of detection. Other determined values of these two contaminants were lower than maximal tolerable amount according to previously valid regulation No. 298/1997 Sb of the Ministry of Health of the Czech Republic given for cow's milk. The contents of each element in the whole of the reference period were in a relatively wide range. Determined levels of Ca, Mg, K, Na, Zn and Cu in goat milk related to the weight of lyophilized milk powder varied from 1.40–8.08 g kg^-1, 0.16–1.42 g kg^-1, 8.16–31.10 g kg^-1, 0.72–5.43 g kg^-1, 7.59–44.10 mg kg^-1, and 0.21–1.46 mg kg^-1 respectively. Determined levels of Ca, Mg, K, Na, Zn and Cu in sheep milk varied from 1.69–9.13 g kg^-1, 0.21–1.36 g kg^-1, 3.53–11.90 g kg^-1, 0.65–5.05 g kg^-1, 13.70–34.30 mg kg^-1, and 0.15–2.10 mg kg^-1 respectively. Statistically higher (P < 0.05) content of potassium was determined in goat milk in comparison with sheep milk. The contents of all followed minerals in milk samples from each farm collected during the lactation period were very variable, but it is not possible to find any direct relationship between the content of studied elements and the date of sampling. It was found that the year has statistically significant influence especially on the content of Ca and Mg in milk of small ruminants.

Key words:

Ca, Cd, Cu, goat milk, K, Mg, Na, Pb, sheep milk, Zn

Quantitation of vitamins A and E in raw sheep milk during lactation period

T. Michlová¹, Š. Horníčková¹, H. Dragounová² and A. Hejtmánková

¹Department of Chemistry, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, the Czech Republic 2Dairy Research Institute Ltd, Prague, the Czech Republic

Abstract:

In this article, the influence of breed and lactation stage on vitamin A and E content in raw sheep milk was studied. The milk of the East Friesian, Romanov and Lacaune sheep breeds was included in the study. The samples were taken once a month throughout lactation. The total average content of vitamin A in raw milk of all sheep breeds during lactation was 0.76 ± 0.19 mg kg-1 of milk and the total average content of vitamin E was 2.86 ± 0.99 mg kg1 of milk. The content of vitamin A and E during lactation varied in respect to the breed type. The highest average content of vitamin A and E was detected in the Romanov sheep:1.01 ± 0.19 mg kg-1 of milk for vitamin A and 4.26 ± 1.90 mg kg-1 for vitamin E. The lowest average value of vitamin A was found in the milk of the East Friesian sheep (0.56 ± 0.10 mg kg-1). This milk showed also the lowest content of vitamin E 2.11 ± 0.53 mg kg-1. The highest content of vitamins was found in summer and at the end of lactation, which is in September, and the lowest values appeared in early lactation, which is in April.

Key words: