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The Effect of Seasonal Thermal Stress on Lipid Mobilisation, Antioxidant Status and Reproductive Performance in Dairy Cows
Author(s) -
Turk R,
Podpečan O,
Mrkun J,
FlegarMeštrić Z,
Perkov S,
Zrimšek P
Publication year - 2015
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.12534
Subject(s) - ice calving , zoology , nefa , biology , insemination , dairy cattle , reproduction , artificial insemination , glycogen , antioxidant , pregnancy , endocrinology , lactation , ecology , insulin , biochemistry , genetics
Contents Heat stress is a major factor contributing to low fertility of dairy cows with a great economic impact in dairy industry. Heat‐stressed dairy cows usually have reduced nutrient intake, resulting in a higher degree of negative energy balance ( NEB ). The aim of this study was to investigate the seasonal thermal effect on lipid metabolism, antioxidant activity and reproductive performance in dairy cows. Thirty‐two healthy dairy heifers were included in the study. According to the ambient temperature, animals were divided into two groups: winter (N = 14) and summer season (N = 18). Metabolic parameters, paraoxonase‐1 ( PON 1) activity and total antioxidant status ( TAS ) were monitored at the time of insemination (basal values) and from 1 week before until 8 weeks after calving. Number of services per conception and calving‐to‐conception ( CC ) interval were calculated from the farm recording data. Serum triglyceride, non‐esterified fatty acids ( NEFA ) and beta‐hydroxybutyrate ( BHB ) concentrations were significantly increased after calving in summer compared to winter, indicating higher degree of NEB in cows during summer. PON 1 activity was significantly decreased after calving in both summer and winter group. TAS concentration was significantly lower in summer than that in winter. A significantly higher number of services were needed for conception in summer compared to winter, and CC interval was significantly longer in summer than that in winter as well. Additionally, reproductive performance significantly correlated with the severity of NEB , suggesting that lipid mobilization and lower antioxidant status contributed to poor reproduction ability in dairy cows during hot months.