Metabolismo energético, proteico e mineral de ovelhas Santa Inês hígidas e com mastite subclínica

Abstract

This study aims to evaluate the energy, protein and mineral metabolism in Santa Inês ewes, both healthy and with subclinical mastitis, followed up during late gestation and lactation periods. Ewes subjected to the same semi-intensive nursing system were followed up. The animals were evaluated according to the following stages: 10 days before parturition (dbp) and 15 days postpartum (dpp), 30 (dpp), 60 (dpp), and 90 (dpp). Blood metabolites were evaluated starting from the stage previous to parturition and whey metabolites were evaluated in the subsequent stages. A screening of the ewes followed up in this study (12 healthy and 18 with subclinical mastitis) was performed after a clinical and bacteriological examination. During lactation, maintaining the same screening criteria, 11 healthy and 20 infected mammary glands were selected; the milk for whey extraction was collected from these glands. Energy profile metabolites (non-esterified fatty acids [NEFAs], ß-hydroxybutyrate [BHB], fructosamine, cholesterol and triglycerides), protein profile (total protein, albumin, urea and creatinine) and mineral profile (iron, copper, zinc, magnesium, total calcium, ionized calcium, sodium, and potassium) were measured in the blood serum. Calcium, sodium and potassium ions, as well as NEFAs and BHB were measured in the whey. Blood biochemistry revealed an influence (P<0,05) of the peripartum and lactation periods on the blood concentrations of NEFAs, BHB, cholesterol, albumin, urea, ionized calcium. An analysis of the whey also revealed an influence on the potassium ion. Ewes with subclinical mastitis showed higher (P<0,05) blood levels of cholesterol, albumin and copper; higher sodium ion concentrations and NEFAs, and lower potassium ion in whey. Good physical score of ewes observed during this study, combined with the biochemical findings, allowed us to conclude that there was a larger energy requirement in the first month of lactation; however, this requirement was not enough to trigger any metabolic disorder or the emergence of ketonemia, and these discrete changes were more apparent in ewes with subclinical mastitis.