at oestrus and cholesterol concentrations were all higher
in cows fed a diet supplemented with LA (n-6) than in cows
that did not receive this supplement. In cows fed a diet
supplemented with LNA (n-3), there was an increase in
oestradiol during the follicular phase. Diet had no effect on
non-esterified fatty acid or insulin concentrations, or on
the duration of the oestrous cycle. The plasma concentration
of 13,14,dihydro-15 keto PGF2a after administration
of 50 iu oxytocin was unaffected by diet on day 15 and day
16 of the oestrous cycle, but showed a greater response on
day 17 in the LA (n-6) supplemented group. Therefore,
the PUFA content of the diet can influence both ovarian
and uterine function in cows. However, further studies
using larger numbers of cows are required to test whether
fertility is also affected by such diets.