Effects of late gestation Calcium salts of fatty acids supplementation to beef cows on offspring pre-weaning growth performance and gene expression.

Objectives were to investigate the effects of supplementing Ca salts of fatty acids to beef cows during late gestation on the pre-weaning growth performance and gene expression of steer progeny. Ninety-six fallcalving, Angus x Simmental cows (BW = 601±76 kg) were randomly assigned into 8 pastures (4 pastures/treatment; 12 cows/pasture), supplemented soyhulls mixed with 80 g/cow/d Strata + 80 g/cow/d Prequel (PUFA, rich in linoleic acid, eicosapentaenoic acid, and docosahexaenoic acid) or 155 g/cow/d EnerGII (SFA/MUFA, rich in palmitic and oleic acids) for 76.5±6.0 d prepartum. Cow/calf pairs were comingled after calving. Biopsies of Longissimus dorsi (LD) and subcutaneous adipose were taken at birth and 3 wk before weaning (186±6 d). The data were analyzed using the MIXED procedure of SAS. Supplementing PUFA increased (P < 0.01) cow plasma eicosapentaenoic acid and docosahexaenoic acid at midpoint of supplementation. At birth, PUFA steers had greater (P < 0.05) plasma EPA and lower (P < 0.01) plasma linolenic acid and oleic acid than SFA/MUFA steers. Weaning BW and pre-weaning ADG of the SFA/MUFA steers tended (P < 0.07) to be greater than PUFA steers. SFA/MUFA steers had increased (P = 0.04) expression of Zfp423 in adipose. There tended to be a treatment×time interaction (P = 0.06) for expression of Myf5 in LD; expression of Myf5 was greatest in SFA/MUFA steers at birth. There was a treatment×time interaction (P = 0.05) for expression of Pax7; expression was greater in SFA/MUFA steers at birth than any treatment at weaning. There were treatment×time interactions (P < 0.01) for expression of Myh7 and C/EBPß in LD; expressions were greatest in PUFA steers at weaning. Supplementing Ca salts of PUFA to beef cows during late gestation altered plasma fatty acid profile of cow and calf, affected gene expression, and decreased offspring growth performance. [ABSTRACT FROM AUTHOR]