Abstract
The aim of this study was to analyze the relationship between the fatty acid profiles of hair of first parity cows and their reproduction and milk performance. Hair samples from 46 German Holstein cows, 50 to 62 d postpartum, were analyzed to assess the relationship. All cows were fed the same diet. The lipid composition of hair was determined by gas chromatography. The fat content in the hair was 0.86 percent. Hair lipids contributed 75.14 percent SFA, 15.81 percent MUFA, and 9.92 percent PUFA. Cows were classified into a high and a low performance group according to their a) length of the interval from calving to first insemination (CFI), b) 100-d protein yield (100-d PY), and c) length of the interval from calving to conception (CC) and 100-d PY. Cows with short CFI or high 100-d PY or short CC and high 100-d PY had significantly greater proportions of de novo synthesized C12:0 (P lesser 0.05) compared with the corresponding low performing groups. Increased proportions of C12:0 in the hair were associated with shorter CFI (r = -0.32, P = 0.033) and greater 100-d PY (r = 0.34, P = 0.021). Furthermore, a discriminant analysis with C12:0 as a variable best predicted short CC and high 100-d PY (error rate 33.5 percent). Greater proportions of de novo synthesized fatty acids in the hair, in particular C12:0, are likely to reflect a sufficient energy availability that is required for fatty acid synthesis in ruminants.