INFLUENCE OF LINOLEIC LINOLENIC ACID RATIO IN THE DIET OF PERIPARTURIENT CATTLE ON PLASMA-CONCENTRATIONS OF PGF2-ALPHA METABOLITE AND PLACENTAL EXPULSION RATE/

Forty-eight cows Holstein Friesian x Dutch Friesian (HFxDF) were rando mly assigned to 2 groups fed 1 of 2 diets (isocaloric and isonitrogeno us but different in linoleic/linolenic acid ratio) from 4 wk before ex pected parturition until 7 d after calving. Effects of the diet on pla sma linoleic/linolenic acid ratio, plasma PGFM levels and placental ex pulsion rate were studied. Dietary treatment resulted in significant d ifferences in linoleic/linolenic acid ratio in blood plasma (1.00+/-.2 2 vs 4.41+/-.53). The placental expulsion rate was not significantly d ifferent between the 2 treatment groups. Plasma PGFM levels, as analyz ed for 28 cows from 30 d before parturition until 1.5 d after parturit ion, were similar for the diets. Cows with a longer placental expulsio n rate had lower PGFM levels at parturition (for instance, placental e xpulsion rate shorter (n=11) and longer (n=17) than 6 h, 1248 vs 2965 pg/ml, residual standard deviation 1185 pg/ml, P<0.01). The results sh ow that the dietary linoleic/linolenic acid ratio can influence the pl asma linoleic/linolenic acid ratio without affecting the placental exp ulsion rate or plasma PGFM levels around parturition. (C) 1998 by Else vier Science Inc.