Associations of pre-lambing body condition score and serum β-hydroxybutyric acid and non-esterified fatty acids concentrations with periparturient health of Chios dairy ewes

Abstract

The objectives of the present study were twofold: (1) to assess the association of body condition score (BCS), β-hydroxybutyric acid (BHBA) and non-esterified fatty acids (NEFA) concentrations in blood serum prior to lambing with the health status of intensively managed dairy ewes during the periparturient period (defined here as 15 days before the expected parturition up to 30 days after lambing), and (2) to evaluate BHBA and NEFA fluctuations and possible association during the latter period. A total of 262 clinically healthy dairy ewes of the Chios breed were used. They were ewe-lambs, primiparous and multiparous animals. Periparturient diseases (pregnancy toxemia, retained fetal membranes, metritis and clinical mastitis) and culling cases (defined as “health disorders”) were recorded. BCS was assessed at 30±3 days before parturition (−30d). Blood samples were obtained at 30±3 (−30d) and 15±3 (−15d) days before the expected parturition as well as 15 (+15d) and 30 (+30d) days after parturition; serum BHBA and NEFA concentrations were determined. A multivariable logistic model was developed to assess the effect of BCS, BHBA and NEFA concentrations at 30d before parturition on “health disorders”. The odds of developing periparturient “health disorders” in normal ewes (BCS 2.75–3.5) at 30 days prepartum were 0.338 times lower when compared with the lean ewes (BCS<2.75, P=0.003). In addition, the odds for a unit increase in BHBA is 2.163 to develop periparturient “health disorders” (P=0.013). A Linear Mixed Effects model indicated a statistically significant effect of time periods on both BHBA (P<0.001) and NEFA (P<0.001) concentrations (log transformed values). Finally, using a weighted correlation coefficient, a significant positive association between BHBA and NEFA concentrations across the study period (r=0.413, P<0.001) was revealed. It was concluded that strategic plans should be established to monitor periparturient health of dairy ewes focusing particularly on BHBA concentration and BCS measurement at 30 days prepartum. The risk for periparturient “health disorders” in ewes was lower when their BCS was between 2.75 and 3.5 and higher when BHBA serum concentrations increased.