Interactions between nutrition, blood metabolic profile and milk composition in dairy goats

The aim of this study was to investigate changes in the concentrations of b lood and milk constituents of dairy goats under the effects of stable diet and grazing during lactation from April to June. The experiment was carried out on 10 dairy goats fed a ration composed of concentrate mixture, sugar beet silage and grass hay during winter season (stable diet), and pasture s eason. Jugular blood and milk samples were taken from all goats during lact ation months of April through June at one-month intervals. The blood concen tration of total protein (TPP), urea, glucose, triacylglycerols, total keto nes, serum non-esterified fattty acids (NEFA), Na, K, Ca, inorganic phospho rus (Pi), Cu, Zn, aspartic amino transferase (AST), gamma-glutamyl transfer ase (GGT), creatine kinase (CK), lactate dehydrogenase (LDH), pH and haemog lobin (Hb) were determined. The measurements of milk contents of fat, prote in, casein, urea, lactose, citric acid, total ketones, pH and titratable ac idity were performed, too. The results showed variations in serum NEFA, pla sma triacylglycerols, Pi , plasma CK and plasma urea during the first month s of lactation. In addition to milk levels of total ketones, citric acid, f at and urea were changed, Highest correlation coefficients were found betwe en plasma and milk urea (r = 0.88; p < 0.001). However, there were correlat ions between milk fat, plasma urea, blood haemoglobin, plasma glucose, plas ma triacylglycerols, blood total ketones and plasma Mg. Citric acid in milk was positively correlated with plasma glucose (r = 0.46; p < 0.01) and neg atively with plasma total protein (r = - 0.31; p < 0.05). In conclusion, hi gh concentration of serum NEFA, blood total ketones and plasma urea in addi tion to the decline in the milk concentrations of citric acid and protein, along with increase in milk concentrations of ketone bodies and urea during the first lactation months were observed and may be associated with corres ponding energy deficit and induce considerable metabolic changes in dairy g oats.