Comparison of different sorting of fatty acids in bovine milk in relation to body condition of Czech Fleckvieh dairy cows Porovnání rozdílného třídění mastných kyselin v mléce ve vztahu k tělesné kondici dojnic českého strakatého plemene

Fatty acids in milk are one of the most important components of milk. The aim of this study was to determinate relationships between groups of fatty acids and body condition score change in Czech Fleckvieh cows. Fatty acids were classificated along its length of chain and its origin. A total of 50 Czech Fleckvieh cows with different parity were included to observation. During the first 4 weeks of lactation, milk samples were collected at a weekly interval and body condition score was assessed. Statistical analyses were performed using Microsoft Office Excel and the procedures MEANS and GLM of SAS 9.1. During the first four week of lactation, the proportions of shortand medium-chain fatty acids as well as de novo synthesised fatty acids increased. Moreover the cows with a greater body condition score change mobilized storage depot fat more intensively, which resulted in higher proportions of dietary and fatty acids originating in depot fat since week 1 of lactation, and long-chain fatty acids since week 2 of lactation. On the contrary, the animals with only a small body condition score change exhibited high proportions of shortand medium-fatty acids as well as de novo synthesised fatty acids in the most part of the period analysed. This indicates negative energy balance in early part of lactation and its compensation during observed period. So, the results confirm the relationships between different groups of milk fatty acids proportion, body condition score and negative energy balance. Both methods of FA sorting were confirmed as appropriate for evaluation of negative energy balance intensity. Further, results emphasize importance the monitoring of body condition, milk composition and good level of herd management in first part of lactation.