The effect of concentrates on production traits, biochemical parameters and thyroid hormones concentration in Dubrovnik sheep fed forage based-diets

Abstract

The research was carried out on 20 Dubrovnik sheep, divided into two groups. During the day, ewes and lambs were out in pasture and in the evening, after returning to the barn, ewes of group I were fed with only hay, and group II, besides hay, received 200 g corn and 100 g wheat bran. Body measurement, assessment of body condition, weighing and blood sampling were carried out in highly pregnant and lactating ewes. The addition of concentrate feed to the ewes´ diets was justified because it improved the ewes´ production traits (higher body weight, lower ewe weight loss per lamb, better body development indices). The significantly higher concentrations of cholesterol, beta-hydroxybutirate and thyroxine hormone in the blood of group II show that metabolic profile indicators may be considered as a good criterion for assessing their nutritional status. The research showed that the genetic potential of Dubrovnik sheep has not been fully exploited so that improved nutrition may significantly improve the ewes´ production traits, which should guarantee the survival of this, the most endangered native Croatian breed of sheep.