Fig. 4. The effect of dietary polyunsaturated fatty acids (PUFAs) on
mean plasma insulin-like growth factor I (IGF-I) concentrations.
IGF-I concentrations were measured twice each day in cows maintained
on three different diets: (i) control (j), (ii) high linolenic acid
(LNA) (n-3) (d) or (iii) high linoleic acid (LA) (n-6) (m) PUFA near
E2 and were centred on the peak of the LH surge. Values are the
estimated marginal means. The pooled SEs (ng ml–1) were: control:
11.5; LNA (n-3): 10.5; and LA (n-6): 10.6. There was no significant
effect of time for any group, but values were significantly higher in
the LA (n-6) group than in the control (P < 0.02) and LNA (n-3)
groups (P < 0.003