engleski

Leptin as indicator of lipomobilisation during lactation in Simmental cows

Aim of the study The aim of the study is to determine potential use of leptin as indicator of lipomobilisation during early lactation in Simmental cows. Introduction High milk production and its direct impact on health and metabolism of the cow needs to be followed routinely in dairy industry. It is worldwide accepted to use BCS change as indirect parameter of lipomobilisation of the cow. BCS is easy to apply in cows of fine constitution such as Holstein cows but not so easy in rough and robust Symmental cows, which still produce significant amount of milk in Croatia and some other countries. In such animals alternative indicator of lipomobilisation is needed.Using metabolic parameters such as NEFA or BHB is not accurate, since it is strongly influenced by onset of cyclicity during and after puerperium. So we needed some other parameter, closely related to fat tissues mobilisation. Materials and methods In our study we followed lactation in 69 Simmental cows during first 10 weeks after parturition. All cows produced more than 25 l of milk per day, aged 4-6 years and were healthy by all means. Blood was collected weekly, at 7 a.m. during 10 weeks. Sera samples were stored at -20°C and analysed using LINCO multispecies RIA kit for leptin. All cows were inseminated at the first visible estrus, and half conceived (32 versus 37). Results We found strong linear correlations between onset and increase of milk production and decrease of leptin concentration. Furthermore, the average leptin values decreased three times (from 6 to 2 ng/ml) during the first 3 weeks after parturition. The onset of pregnancy did not influence leptin values probably due to the predominant influence of energy demands for lactation. Conclusions Our research has shown that leptin concentrations vary markedly after calving in Simmental cows but after comparison with other with other parameters (such as BCS, NEFA or BHB) a more rapid and practitioner-based method (rapid test) should be developed for use on-farm.

leptin; lipomobilisation; lactation; Simmental cows

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