Programming effect of dietary fatty acids on performance of Holstein heifers from birth through first lactation

The objective was to evaluate the effect of supplementation of essential fatty acids (FA), primarily linoleic acid, to prepartum cows during the last 2 mo of pregnancy and to their subsequent heifers, during the preweaning period on the productive and reproductive responses of heifers for their first 3 years of life. During the last 8 weeks of pregnancy, Holstein cattle (n = 96) were fed either no fat supplement (CTL), a saturated FA (SFA) supplement enriched in C16:0 and C18:0, or an unsaturated FA supplement enriched in linoleic acid (EFA). Newly born heifers (n = 56) from these dams were blocked by dam diet and fed a milk replacer (MR) for 60 d with either low linoleic acid (LLA) or high linoleic acid (HLA) concentration. The MR was the sole feedstuff during the first 30 d. A grain mix with minimal linoleic acid was offered between 31 and 60 d of life. Profile of FA in colostrum reflected that of dam diets. Profiles of FA in plasma of heifers at 30 and 60 d of age reflected that of MR consumed. Heifers fed HLA compared with LLA MR had increased proportions (g/100 g of FA) of linoleic acid (45.8 vs. 40.7, P < 0.01), α-linolenic acid (0.83 vs. 0.66, P < 0.01) and lowered proportions (P < 0.01) of C12:0 and C14:0 in plasma. The maternal diet fed prepartum also did not change the plasma metabolic profile and productive performance of heifers, but heifers fed HLA compared with LLA MR had or tended to have increased concentrations of anabolic metabolites and hormones coupled with a better body weight gain and greater conversion of dry matter intake into body weight (BW). Heifers born from dams supplemented with fat prepartum tended to have a greater number of artificial inseminations at first pregnancy (2.53 vs. 1.85, P = 0.08). However, after correcting for BW and predicted transmitted ability (PTA) of the parents, heifers born from dams supplemented with fat tended to produce more milk (9100 vs. 8415 kg, P = 0.10) and more protein (277 vs. 256 kg, P = 0.09). Heifers fed HLA instead of LLA MR produced more milk protein (283 vs. 258 kg, P = 0.04) and tended to produce more fat (350 vs. 319 kg, P = 0.10), coupled with a numerical increase in total milk yield (9161 vs. 8582 kg, P = 0.14). Strategic feeding of FA during late uterine life and preweaning appears to enhance milk production of heifers in their first lactation.