Relationship between selected indicators of milk and blood in sheep

Abstract

Changes in the composition of milk and blood were studied from the seventh to the 170th days of lactation in ten time intervals (i.e. between 9 March and 29 August) in 22 ewes (12 of the Cigaya breed, and ten crosses with a 62.5 and 37.5% proportion of the Cigaya and East Friesian breeds, respectively). There were variations in the concentrations of milk constituents, the highest in somatic cell counts (153.6%), vitamin A (73.7%) and Cu (62.8%). Variable blood indicators were urea (50.3%), vitamin E (37.9%) and Zn (22.1%). When estimating interrelationships between selected blood and milk indicators, the effect of stage of lactation was not taken into account. The highest correlation coefficients were between urea in blood plasma and milk ( r = 0.90 + +). The correlations between level of milk fat to total blood plasma protein, vitamin E, vitamin A, pH of blood and plasma urea were r = 0.56 + +, r = 0.46 + +, r = 0.33 + +, r = −0.43 + +, and r = 0.33 + +, respectively. Mineral levels in milk were less dependent on the metabolic profile of the blood: the most significant relationships were for Cu and Zn in milk. The most important macroelements of milk, Ca and P, were not significantly influenced by nutrition. The relationships between the levels of the majority of minerals in blood plasma and in milk, with the exception of K, were significant.